QEMU QMP reference

1.7.1 Block core (VM unrelated)

Object: SnapshotInfo ¶

Members:

id: string

unique snapshot id

name: string

user chosen name

vm-state-size: int

size of the VM state

date-sec: int

UTC date of the snapshot in seconds

date-nsec: int

fractional part in nano seconds to be used with date-sec

vm-clock-sec: int

VM clock relative to boot in seconds

vm-clock-nsec: int

fractional part in nano seconds to be used with vm-clock-sec

Since: 1.3

Object: ImageInfoSpecificQCow2EncryptionBase ¶

Members:

format: BlockdevQcow2EncryptionFormat

The encryption format

Since: 2.10

Object: ImageInfoSpecificQCow2Encryption ¶

Members:

The members of ImageInfoSpecificQCow2EncryptionBase

The members of QCryptoBlockInfoQCow when format is "aes"

The members of QCryptoBlockInfoLUKS when format is "luks"

Since: 2.10

Object: ImageInfoSpecificQCow2 ¶

Members:

compat: string

compatibility level

lazy-refcounts: boolean (optional)

on or off; only valid for compat >= 1.1

corrupt: boolean (optional)

true if the image has been marked corrupt; only valid for compat >= 1.1 (since 2.2)

refcount-bits: int

width of a refcount entry in bits (since 2.3)

encrypt: ImageInfoSpecificQCow2Encryption (optional)

details about encryption parameters; only set if image is encrypted (since 2.10)

Since: 1.7

Object: ImageInfoSpecificVmdk ¶

Members:

create-type: string

The create type of VMDK image

cid: int

Content id of image

parent-cid: int

Parent VMDK image’s cid

extents: array of ImageInfo

List of extent files

Since: 1.7

Object: ImageInfoSpecific ¶

A discriminated record of image format specific information structures.

Members:

type

One of "qcow2", "vmdk", "luks"

data: ImageInfoSpecificQCow2 when type is "qcow2"

data: ImageInfoSpecificVmdk when type is "vmdk"

data: QCryptoBlockInfoLUKS when type is "luks"

Since: 1.7

Object: ImageInfo ¶

Information about a QEMU image file

Members:

filename: string

name of the image file

format: string

format of the image file

virtual-size: int

maximum capacity in bytes of the image

actual-size: int (optional)

actual size on disk in bytes of the image

dirty-flag: boolean (optional)

true if image is not cleanly closed

cluster-size: int (optional)

size of a cluster in bytes

encrypted: boolean (optional)

true if the image is encrypted

compressed: boolean (optional)

true if the image is compressed (Since 1.7)

backing-filename: string (optional)

name of the backing file

full-backing-filename: string (optional)

full path of the backing file

backing-filename-format: string (optional)

the format of the backing file

snapshots: array of SnapshotInfo (optional)

list of VM snapshots

backing-image: ImageInfo (optional)

info of the backing image (since 1.6)

format-specific: ImageInfoSpecific (optional)

structure supplying additional format-specific information (since 1.7)

Since: 1.3

Object: ImageCheck ¶

Information about a QEMU image file check

Members:

filename: string

name of the image file checked

format: string

format of the image file checked

check-errors: int

number of unexpected errors occurred during check

image-end-offset: int (optional)

offset (in bytes) where the image ends, this field is present if the driver for the image format supports it

corruptions: int (optional)

number of corruptions found during the check if any

leaks: int (optional)

number of leaks found during the check if any

corruptions-fixed: int (optional)

number of corruptions fixed during the check if any

leaks-fixed: int (optional)

number of leaks fixed during the check if any

total-clusters: int (optional)

total number of clusters, this field is present if the driver for the image format supports it

allocated-clusters: int (optional)

total number of allocated clusters, this field is present if the driver for the image format supports it

fragmented-clusters: int (optional)

total number of fragmented clusters, this field is present if the driver for the image format supports it

compressed-clusters: int (optional)

total number of compressed clusters, this field is present if the driver for the image format supports it

Since: 1.4

Object: MapEntry ¶

Mapping information from a virtual block range to a host file range

Members:

start: int

the start byte of the mapped virtual range

length: int

the number of bytes of the mapped virtual range

data: boolean

whether the mapped range has data

zero: boolean

whether the virtual blocks are zeroed

depth: int

the depth of the mapping

offset: int (optional)

the offset in file that the virtual sectors are mapped to

filename: string (optional)

filename that is referred to by offset

Since: 2.6

Object: BlockdevCacheInfo ¶

Cache mode information for a block device

Members:

writeback: boolean

true if writeback mode is enabled

direct: boolean

true if the host page cache is bypassed (O_DIRECT)

no-flush: boolean

true if flush requests are ignored for the device

Since: 2.3

Object: BlockDeviceInfo ¶

Information about the backing device for a block device.

Members:

file: string

the filename of the backing device

node-name: string (optional)

the name of the block driver node (Since 2.0)

ro: boolean

true if the backing device was open read-only

drv: string

the name of the block format used to open the backing device. As of 0.14.0 this can be: ’blkdebug’, ’bochs’, ’cloop’, ’cow’, ’dmg’, ’file’, ’file’, ’ftp’, ’ftps’, ’host_cdrom’, ’host_device’, ’http’, ’https’, ’luks’, ’nbd’, ’parallels’, ’qcow’, ’qcow2’, ’raw’, ’vdi’, ’vmdk’, ’vpc’, ’vvfat’ 2.2: ’archipelago’ added, ’cow’ dropped 2.3: ’host_floppy’ deprecated 2.5: ’host_floppy’ dropped 2.6: ’luks’ added 2.8: ’replication’ added, ’tftp’ dropped 2.9: ’archipelago’ dropped

backing_file: string (optional)

the name of the backing file (for copy-on-write)

backing_file_depth: int

number of files in the backing file chain (since: 1.2)

encrypted: boolean

true if the backing device is encrypted

encryption_key_missing: boolean

Deprecated; always false

detect_zeroes: BlockdevDetectZeroesOptions

detect and optimize zero writes (Since 2.1)

bps: int

total throughput limit in bytes per second is specified

bps_rd: int

read throughput limit in bytes per second is specified

bps_wr: int

write throughput limit in bytes per second is specified

iops: int

total I/O operations per second is specified

iops_rd: int

read I/O operations per second is specified

iops_wr: int

write I/O operations per second is specified

image: ImageInfo

the info of image used (since: 1.6)

bps_max: int (optional)

total throughput limit during bursts, in bytes (Since 1.7)

bps_rd_max: int (optional)

read throughput limit during bursts, in bytes (Since 1.7)

bps_wr_max: int (optional)

write throughput limit during bursts, in bytes (Since 1.7)

iops_max: int (optional)

total I/O operations per second during bursts, in bytes (Since 1.7)

iops_rd_max: int (optional)

read I/O operations per second during bursts, in bytes (Since 1.7)

iops_wr_max: int (optional)

write I/O operations per second during bursts, in bytes (Since 1.7)

bps_max_length: int (optional)

maximum length of the bps_max burst period, in seconds. (Since 2.6)

bps_rd_max_length: int (optional)

maximum length of the bps_rd_max burst period, in seconds. (Since 2.6)

bps_wr_max_length: int (optional)

maximum length of the bps_wr_max burst period, in seconds. (Since 2.6)

iops_max_length: int (optional)

maximum length of the iops burst period, in seconds. (Since 2.6)

iops_rd_max_length: int (optional)

maximum length of the iops_rd_max burst period, in seconds. (Since 2.6)

iops_wr_max_length: int (optional)

maximum length of the iops_wr_max burst period, in seconds. (Since 2.6)

iops_size: int (optional)

an I/O size in bytes (Since 1.7)

group: string (optional)

throttle group name (Since 2.4)

cache: BlockdevCacheInfo

the cache mode used for the block device (since: 2.3)

write_threshold: int

configured write threshold for the device. 0 if disabled. (Since 2.3)

Since: 0.14.0

Enum: BlockDeviceIoStatus ¶

An enumeration of block device I/O status.

Values:

ok

The last I/O operation has succeeded

failed

The last I/O operation has failed

nospace

The last I/O operation has failed due to a no-space condition

Since: 1.0

Object: BlockDeviceMapEntry ¶

Entry in the metadata map of the device (returned by "qemu-img map")

Members:

start: int

Offset in the image of the first byte described by this entry (in bytes)

length: int

Length of the range described by this entry (in bytes)

depth: int

Number of layers (0 = top image, 1 = top image’s backing file, etc.) before reaching one for which the range is allocated. The value is in the range 0 to the depth of the image chain - 1.

zero: boolean

the sectors in this range read as zeros

data: boolean

reading the image will actually read data from a file (in particular, if offset is present this means that the sectors are not simply preallocated, but contain actual data in raw format)

offset: int (optional)

if present, the image file stores the data for this range in raw format at the given offset.

Since: 1.7

Enum: DirtyBitmapStatus ¶

An enumeration of possible states that a dirty bitmap can report to the user.

Values:

frozen

The bitmap is currently in-use by a backup operation or block job, and is immutable.

disabled

The bitmap is currently in-use by an internal operation and is read-only. It can still be deleted.

active

The bitmap is actively monitoring for new writes, and can be cleared, deleted, or used for backup operations.

locked

The bitmap is currently in-use by some operation and can not be cleared, deleted, or used for backup operations. (Since 2.12)

Since: 2.4

Object: BlockDirtyInfo ¶

Block dirty bitmap information.

Members:

name: string (optional)

the name of the dirty bitmap (Since 2.4)

count: int

number of dirty bytes according to the dirty bitmap

granularity: int

granularity of the dirty bitmap in bytes (since 1.4)

status: DirtyBitmapStatus

current status of the dirty bitmap (since 2.4)

Since: 1.3

Object: BlockLatencyHistogramInfo ¶

Block latency histogram.

Members:

boundaries: array of int

list of interval boundary values in nanoseconds, all greater than zero and in ascending order. For example, the list [10, 50, 100] produces the following histogram intervals: [0, 10), [10, 50), [50, 100), [100, +inf).

bins: array of int

list of io request counts corresponding to histogram intervals. len(bins) = len(boundaries) + 1 For the example above, bins may be something like [3, 1, 5, 2], and corresponding histogram looks like:

5| * 4| * 3| 2| * 1| +—————— 10 50 100

Since: 2.12

Command: x-block-latency-histogram-set ¶

Manage read, write and flush latency histograms for the device.

If only device parameter is specified, remove all present latency histograms for the device. Otherwise, add/reset some of (or all) latency histograms.

Arguments:

device: string

device name to set latency histogram for.

boundaries: array of int (optional)

list of interval boundary values (see description in BlockLatencyHistogramInfo definition). If specified, all latency histograms are removed, and empty ones created for all io types with intervals corresponding to boundaries (except for io types, for which specific boundaries are set through the following parameters).

boundaries-read: array of int (optional)

list of interval boundary values for read latency histogram. If specified, old read latency histogram is removed, and empty one created with intervals corresponding to boundaries-read. The parameter has higher priority then boundaries.

boundaries-write: array of int (optional)

list of interval boundary values for write latency histogram.

boundaries-flush: array of int (optional)

list of interval boundary values for flush latency histogram.

Returns: error if device is not found or any boundary arrays are invalid.

Since: 2.12

Example:

set new histograms for all io types with intervals
[0, 10), [10, 50), [50, 100), [100, +inf):

-> { "execute": "block-latency-histogram-set",
     "arguments": { "device": "drive0",
                    "boundaries": [10, 50, 100] } }
<- { "return": {} }

Example:

set new histogram only for write, other histograms will remain
not changed (or not created):

-> { "execute": "block-latency-histogram-set",
     "arguments": { "device": "drive0",
                    "boundaries-write": [10, 50, 100] } }
<- { "return": {} }

Example:

set new histograms with the following intervals:
  read, flush: [0, 10), [10, 50), [50, 100), [100, +inf)
  write: [0, 1000), [1000, 5000), [5000, +inf)

-> { "execute": "block-latency-histogram-set",
     "arguments": { "device": "drive0",
                    "boundaries": [10, 50, 100],
                    "boundaries-write": [1000, 5000] } }
<- { "return": {} }

Example:

remove all latency histograms:

-> { "execute": "block-latency-histogram-set",
     "arguments": { "device": "drive0" } }
<- { "return": {} }

Object: BlockInfo ¶

Block device information. This structure describes a virtual device and the backing device associated with it.

Members:

device: string

The device name associated with the virtual device.

qdev: string (optional)

The qdev ID, or if no ID is assigned, the QOM path of the block device. (since 2.10)

type: string

This field is returned only for compatibility reasons, it should not be used (always returns ’unknown’)

removable: boolean

True if the device supports removable media.

locked: boolean

True if the guest has locked this device from having its media removed

tray_open: boolean (optional)

True if the device’s tray is open (only present if it has a tray)

dirty-bitmaps: array of BlockDirtyInfo (optional)

dirty bitmaps information (only present if the driver has one or more dirty bitmaps) (Since 2.0)

io-status: BlockDeviceIoStatus (optional)

BlockDeviceIoStatus. Only present if the device supports it and the VM is configured to stop on errors (supported device models: virtio-blk, IDE, SCSI except scsi-generic)

inserted: BlockDeviceInfo (optional)

BlockDeviceInfo describing the device if media is present

Since: 0.14.0

Object: BlockMeasureInfo ¶

Image file size calculation information. This structure describes the size requirements for creating a new image file.

The size requirements depend on the new image file format. File size always equals virtual disk size for the ’raw’ format, even for sparse POSIX files. Compact formats such as ’qcow2’ represent unallocated and zero regions efficiently so file size may be smaller than virtual disk size.

The values are upper bounds that are guaranteed to fit the new image file. Subsequent modification, such as internal snapshot or bitmap creation, may require additional space and is not covered here.

Members:

required: int

Size required for a new image file, in bytes.

fully-allocated: int

Image file size, in bytes, once data has been written to all sectors.

Since: 2.10

Command: query-block ¶

Get a list of BlockInfo for all virtual block devices.

Returns: a list of BlockInfo describing each virtual block device. Filter nodes that were created implicitly are skipped over.

Since: 0.14.0

Example:

-> { "execute": "query-block" }
<- {
      "return":[
         {
            "io-status": "ok",
            "device":"ide0-hd0",
            "locked":false,
            "removable":false,
            "inserted":{
               "ro":false,
               "drv":"qcow2",
               "encrypted":false,
               "file":"disks/test.qcow2",
               "backing_file_depth":1,
               "bps":1000000,
               "bps_rd":0,
               "bps_wr":0,
               "iops":1000000,
               "iops_rd":0,
               "iops_wr":0,
               "bps_max": 8000000,
               "bps_rd_max": 0,
               "bps_wr_max": 0,
               "iops_max": 0,
               "iops_rd_max": 0,
               "iops_wr_max": 0,
               "iops_size": 0,
               "detect_zeroes": "on",
               "write_threshold": 0,
               "image":{
                  "filename":"disks/test.qcow2",
                  "format":"qcow2",
                  "virtual-size":2048000,
                  "backing_file":"base.qcow2",
                  "full-backing-filename":"disks/base.qcow2",
                  "backing-filename-format":"qcow2",
                  "snapshots":[
                     {
                        "id": "1",
                        "name": "snapshot1",
                        "vm-state-size": 0,
                        "date-sec": 10000200,
                        "date-nsec": 12,
                        "vm-clock-sec": 206,
                        "vm-clock-nsec": 30
                     }
                  ],
                  "backing-image":{
                      "filename":"disks/base.qcow2",
                      "format":"qcow2",
                      "virtual-size":2048000
                  }
               }
            },
            "qdev": "ide_disk",
            "type":"unknown"
         },
         {
            "io-status": "ok",
            "device":"ide1-cd0",
            "locked":false,
            "removable":true,
            "qdev": "/machine/unattached/device[23]",
            "tray_open": false,
            "type":"unknown"
         },
         {
            "device":"floppy0",
            "locked":false,
            "removable":true,
            "qdev": "/machine/unattached/device[20]",
            "type":"unknown"
         },
         {
            "device":"sd0",
            "locked":false,
            "removable":true,
            "type":"unknown"
         }
      ]
   }

Object: BlockDeviceTimedStats ¶

Statistics of a block device during a given interval of time.

Members:

interval_length: int

Interval used for calculating the statistics, in seconds.

min_rd_latency_ns: int

Minimum latency of read operations in the defined interval, in nanoseconds.

min_wr_latency_ns: int

Minimum latency of write operations in the defined interval, in nanoseconds.

min_flush_latency_ns: int

Minimum latency of flush operations in the defined interval, in nanoseconds.

max_rd_latency_ns: int

Maximum latency of read operations in the defined interval, in nanoseconds.

max_wr_latency_ns: int

Maximum latency of write operations in the defined interval, in nanoseconds.

max_flush_latency_ns: int

Maximum latency of flush operations in the defined interval, in nanoseconds.

avg_rd_latency_ns: int

Average latency of read operations in the defined interval, in nanoseconds.

avg_wr_latency_ns: int

Average latency of write operations in the defined interval, in nanoseconds.

avg_flush_latency_ns: int

Average latency of flush operations in the defined interval, in nanoseconds.

avg_rd_queue_depth: number

Average number of pending read operations in the defined interval.

avg_wr_queue_depth: number

Average number of pending write operations in the defined interval.

Since: 2.5

Object: BlockDeviceStats ¶

Statistics of a virtual block device or a block backing device.

Members:

rd_bytes: int

The number of bytes read by the device.

wr_bytes: int

The number of bytes written by the device.

rd_operations: int

The number of read operations performed by the device.

wr_operations: int

The number of write operations performed by the device.

flush_operations: int

The number of cache flush operations performed by the device (since 0.15.0)

flush_total_time_ns: int

Total time spend on cache flushes in nano-seconds (since 0.15.0).

wr_total_time_ns: int

Total time spend on writes in nano-seconds (since 0.15.0).

rd_total_time_ns: int

Total_time_spend on reads in nano-seconds (since 0.15.0).

wr_highest_offset: int

The offset after the greatest byte written to the device. The intended use of this information is for growable sparse files (like qcow2) that are used on top of a physical device.

rd_merged: int

Number of read requests that have been merged into another request (Since 2.3).

wr_merged: int

Number of write requests that have been merged into another request (Since 2.3).

idle_time_ns: int (optional)

Time since the last I/O operation, in nanoseconds. If the field is absent it means that there haven’t been any operations yet (Since 2.5).

failed_rd_operations: int

The number of failed read operations performed by the device (Since 2.5)

failed_wr_operations: int

The number of failed write operations performed by the device (Since 2.5)

failed_flush_operations: int

The number of failed flush operations performed by the device (Since 2.5)

invalid_rd_operations: int

The number of invalid read operations performed by the device (Since 2.5)

invalid_wr_operations: int

The number of invalid write operations performed by the device (Since 2.5)

invalid_flush_operations: int

The number of invalid flush operations performed by the device (Since 2.5)

account_invalid: boolean

Whether invalid operations are included in the last access statistics (Since 2.5)

account_failed: boolean

Whether failed operations are included in the latency and last access statistics (Since 2.5)

timed_stats: array of BlockDeviceTimedStats

Statistics specific to the set of previously defined intervals of time (Since 2.5)

x_rd_latency_histogram: BlockLatencyHistogramInfo (optional)

BlockLatencyHistogramInfo. (Since 2.12)

x_wr_latency_histogram: BlockLatencyHistogramInfo (optional)

BlockLatencyHistogramInfo. (Since 2.12)

x_flush_latency_histogram: BlockLatencyHistogramInfo (optional)

BlockLatencyHistogramInfo. (Since 2.12)

Since: 0.14.0

Object: BlockStats ¶

Statistics of a virtual block device or a block backing device.

Members:

device: string (optional)

If the stats are for a virtual block device, the name corresponding to the virtual block device.

node-name: string (optional)

The node name of the device. (Since 2.3)

stats: BlockDeviceStats

A BlockDeviceStats for the device.

parent: BlockStats (optional)

This describes the file block device if it has one. Contains recursively the statistics of the underlying protocol (e.g. the host file for a qcow2 image). If there is no underlying protocol, this field is omitted

backing: BlockStats (optional)

This describes the backing block device if it has one. (Since 2.0)

Since: 0.14.0

Command: query-blockstats ¶

Query the BlockStats for all virtual block devices.

Arguments:

query-nodes: boolean (optional)

If true, the command will query all the block nodes that have a node name, in a list which will include "parent" information, but not "backing". If false or omitted, the behavior is as before - query all the device backends, recursively including their "parent" and "backing". Filter nodes that were created implicitly are skipped over in this mode. (Since 2.3)

Returns: A list of BlockStats for each virtual block devices.

Since: 0.14.0

Example:

-> { "execute": "query-blockstats" }
<- {
      "return":[
         {
            "device":"ide0-hd0",
            "parent":{
               "stats":{
                  "wr_highest_offset":3686448128,
                  "wr_bytes":9786368,
                  "wr_operations":751,
                  "rd_bytes":122567168,
                  "rd_operations":36772
                  "wr_total_times_ns":313253456
                  "rd_total_times_ns":3465673657
                  "flush_total_times_ns":49653
                  "flush_operations":61,
                  "rd_merged":0,
                  "wr_merged":0,
                  "idle_time_ns":2953431879,
                  "account_invalid":true,
                  "account_failed":false
               }
            },
            "stats":{
               "wr_highest_offset":2821110784,
               "wr_bytes":9786368,
               "wr_operations":692,
               "rd_bytes":122739200,
               "rd_operations":36604
               "flush_operations":51,
               "wr_total_times_ns":313253456
               "rd_total_times_ns":3465673657
               "flush_total_times_ns":49653,
               "rd_merged":0,
               "wr_merged":0,
               "idle_time_ns":2953431879,
               "account_invalid":true,
               "account_failed":false
            }
         },
         {
            "device":"ide1-cd0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            }
         },
         {
            "device":"floppy0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            }
         },
         {
            "device":"sd0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            }
         }
      ]
   }

Enum: BlockdevOnError ¶

An enumeration of possible behaviors for errors on I/O operations. The exact meaning depends on whether the I/O was initiated by a guest or by a block job

Values:

report

for guest operations, report the error to the guest; for jobs, cancel the job

ignore

ignore the error, only report a QMP event (BLOCK_IO_ERROR or BLOCK_JOB_ERROR)

enospc

same as stop on ENOSPC, same as report otherwise.

stop

for guest operations, stop the virtual machine; for jobs, pause the job

auto

inherit the error handling policy of the backend (since: 2.7)

Since: 1.3

Enum: MirrorSyncMode ¶

An enumeration of possible behaviors for the initial synchronization phase of storage mirroring.

Values:

top

copies data in the topmost image to the destination

full

copies data from all images to the destination

none

only copy data written from now on

incremental

only copy data described by the dirty bitmap. Since: 2.4

Since: 1.3

Enum: BlockJobType ¶

Type of a block job.

Values:

commit

block commit job type, see "block-commit"

stream

block stream job type, see "block-stream"

mirror

drive mirror job type, see "drive-mirror"

backup

drive backup job type, see "drive-backup"

Since: 1.7

Enum: BlockJobVerb ¶

Represents command verbs that can be applied to a blockjob.

Values:

cancel

see block-job-cancel

pause

see block-job-pause

resume

see block-job-resume

set-speed

see block-job-set-speed

complete

see block-job-complete

dismiss

see block-job-dismiss

finalize

see block-job-finalize

Since: 2.12

Enum: BlockJobStatus ¶

Indicates the present state of a given blockjob in its lifetime.

Values:

undefined

Erroneous, default state. Should not ever be visible.

created

The job has been created, but not yet started.

running

The job is currently running.

paused

The job is running, but paused. The pause may be requested by either the QMP user or by internal processes.

ready

The job is running, but is ready for the user to signal completion. This is used for long-running jobs like mirror that are designed to run indefinitely.

standby

The job is ready, but paused. This is nearly identical to paused. The job may return to ready or otherwise be canceled.

waiting

The job is waiting for other jobs in the transaction to converge to the waiting state. This status will likely not be visible for the last job in a transaction.

pending

The job has finished its work, but has finalization steps that it needs to make prior to completing. These changes may require manual intervention by the management process if manual was set to true. These changes may still fail.

aborting

The job is in the process of being aborted, and will finish with an error. The job will afterwards report that it is concluded. This status may not be visible to the management process.

concluded

The job has finished all work. If manual was set to true, the job will remain in the query list until it is dismissed.

null

The job is in the process of being dismantled. This state should not ever be visible externally.

Since: 2.12

Object: BlockJobInfo ¶

Information about a long-running block device operation.

Members:

type: string

the job type (’stream’ for image streaming)

device: string

The job identifier. Originally the device name but other values are allowed since QEMU 2.7

len: int

the maximum progress value

busy: boolean

false if the job is known to be in a quiescent state, with no pending I/O. Since 1.3.

paused: boolean

whether the job is paused or, if busy is true, will pause itself as soon as possible. Since 1.3.

offset: int

the current progress value

speed: int

the rate limit, bytes per second

io-status: BlockDeviceIoStatus

the status of the job (since 1.3)

ready: boolean

true if the job may be completed (since 2.2)

status: BlockJobStatus

Current job state/status (since 2.12)

auto-finalize: boolean

Job will finalize itself when PENDING, moving to the CONCLUDED state. (since 2.12)

auto-dismiss: boolean

Job will dismiss itself when CONCLUDED, moving to the NULL state and disappearing from the query list. (since 2.12)

error: string (optional)

Error information if the job did not complete successfully. Not set if the job completed successfully. (since 2.12.1)

Since: 1.1

Command: query-block-jobs ¶

Return information about long-running block device operations.

Returns: a list of BlockJobInfo for each active block job

Since: 1.1

Command: block_passwd ¶

This command sets the password of a block device that has not been open with a password and requires one.

This command is now obsolete and will always return an error since 2.10

Arguments:

device: string (optional)

Not documented

node-name: string (optional)

Not documented

password: string

Not documented

Command: block_resize ¶

Resize a block image while a guest is running.

Either device or node-name must be set but not both.

Arguments:

device: string (optional)

the name of the device to get the image resized

node-name: string (optional)

graph node name to get the image resized (Since 2.0)

size: int

new image size in bytes

Returns: nothing on success If device is not a valid block device, DeviceNotFound

Since: 0.14.0

Example:

-> { "execute": "block_resize",
     "arguments": { "device": "scratch", "size": 1073741824 } }
<- { "return": {} }

Enum: NewImageMode ¶

An enumeration that tells QEMU how to set the backing file path in a new image file.

Values:

existing

QEMU should look for an existing image file.

absolute-paths

QEMU should create a new image with absolute paths for the backing file. If there is no backing file available, the new image will not be backed either.

Since: 1.1

Object: BlockdevSnapshotSync ¶

Either device or node-name must be set but not both.

Members:

device: string (optional)

the name of the device to generate the snapshot from.

node-name: string (optional)

graph node name to generate the snapshot from (Since 2.0)

snapshot-file: string

the target of the new image. If the file exists, or if it is a device, the snapshot will be created in the existing file/device. Otherwise, a new file will be created.

snapshot-node-name: string (optional)

the graph node name of the new image (Since 2.0)

format: string (optional)

the format of the snapshot image, default is ’qcow2’.

mode: NewImageMode (optional)

whether and how QEMU should create a new image, default is ’absolute-paths’.

Object: BlockdevSnapshot ¶

Members:

node: string

device or node name that will have a snapshot created.

overlay: string

reference to the existing block device that will become the overlay of node, as part of creating the snapshot. It must not have a current backing file (this can be achieved by passing "backing": null to blockdev-add).

Since: 2.5

Object: DriveBackup ¶

Members:

job-id: string (optional)

identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

device: string

the device name or node-name of a root node which should be copied.

target: string

the target of the new image. If the file exists, or if it is a device, the existing file/device will be used as the new destination. If it does not exist, a new file will be created.

format: string (optional)

the format of the new destination, default is to probe if mode is ’existing’, else the format of the source

sync: MirrorSyncMode

what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, from a dirty bitmap, or only new I/O).

mode: NewImageMode (optional)

whether and how QEMU should create a new image, default is ’absolute-paths’.

speed: int (optional)

the maximum speed, in bytes per second

bitmap: string (optional)

the name of dirty bitmap if sync is "incremental". Must be present if sync is "incremental", must NOT be present otherwise. (Since 2.4)

compress: boolean (optional)

true to compress data, if the target format supports it. (default: false) (since 2.8)

on-source-error: BlockdevOnError (optional)

the action to take on an error on the source, default ’report’. ’stop’ and ’enospc’ can only be used if the block device supports io-status (see BlockInfo).

on-target-error: BlockdevOnError (optional)

the action to take on an error on the target, default ’report’ (no limitations, since this applies to a different block device than device).

auto-finalize: boolean (optional)

When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 2.12)

auto-dismiss: boolean (optional)

When false, this job will wait in a CONCLUDED state after it has completed ceased all work, and wait for block-job-dismiss. When true, this job will automatically disappear from the query list without user intervention. Defaults to true. (Since 2.12)

Note: on-source-error and on-target-error only affect background I/O. If an error occurs during a guest write request, the device’s rerror/werror actions will be used.

Since: 1.6

Object: BlockdevBackup ¶

Members:

job-id: string (optional)

identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

device: string

the device name or node-name of a root node which should be copied.

target: string

the device name or node-name of the backup target node.

sync: MirrorSyncMode

what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).

speed: int (optional)

the maximum speed, in bytes per second. The default is 0, for unlimited.

compress: boolean (optional)

true to compress data, if the target format supports it. (default: false) (since 2.8)

on-source-error: BlockdevOnError (optional)

the action to take on an error on the source, default ’report’. ’stop’ and ’enospc’ can only be used if the block device supports io-status (see BlockInfo).

on-target-error: BlockdevOnError (optional)

the action to take on an error on the target, default ’report’ (no limitations, since this applies to a different block device than device).

auto-finalize: boolean (optional)

When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize. When true, this job will automatically perform its abort or commit actions. Defaults to true. (Since 2.12)

auto-dismiss: boolean (optional)

When false, this job will wait in a CONCLUDED state after it has completed ceased all work, and wait for block-job-dismiss. When true, this job will automatically disappear from the query list without user intervention. Defaults to true. (Since 2.12)

Note: on-source-error and on-target-error only affect background I/O. If an error occurs during a guest write request, the device’s rerror/werror actions will be used.

Since: 2.3

Command: blockdev-snapshot-sync ¶

Generates a synchronous snapshot of a block device.

For the arguments, see the documentation of BlockdevSnapshotSync.

Returns: nothing on success If device is not a valid block device, DeviceNotFound

Since: 0.14.0

Example:

-> { "execute": "blockdev-snapshot-sync",
     "arguments": { "device": "ide-hd0",
                    "snapshot-file":
                    "/some/place/my-image",
                    "format": "qcow2" } }
<- { "return": {} }

Command: blockdev-snapshot ¶

Generates a snapshot of a block device.

Create a snapshot, by installing ’node’ as the backing image of ’overlay’. Additionally, if ’node’ is associated with a block device, the block device changes to using ’overlay’ as its new active image.

For the arguments, see the documentation of BlockdevSnapshot.

Since: 2.5

Example:

-> { "execute": "blockdev-add",
     "arguments": { "driver": "qcow2",
                    "node-name": "node1534",
                    "file": { "driver": "file",
                              "filename": "hd1.qcow2" },
                    "backing": null } }

<- { "return": {} }

-> { "execute": "blockdev-snapshot",
     "arguments": { "node": "ide-hd0",
                    "overlay": "node1534" } }
<- { "return": {} }

Command: change-backing-file ¶

Change the backing file in the image file metadata. This does not cause QEMU to reopen the image file to reparse the backing filename (it may, however, perform a reopen to change permissions from r/o -> r/w -> r/o, if needed). The new backing file string is written into the image file metadata, and the QEMU internal strings are updated.

Arguments:

image-node-name: string

The name of the block driver state node of the image to modify. The "device" argument is used to verify "image-node-name" is in the chain described by "device".

device: string

The device name or node-name of the root node that owns image-node-name.

backing-file: string

The string to write as the backing file. This string is not validated, so care should be taken when specifying the string or the image chain may not be able to be reopened again.

Returns: Nothing on success

If "device" does not exist or cannot be determined, DeviceNotFound

Since: 2.1

Command: block-commit ¶

Live commit of data from overlay image nodes into backing nodes - i.e., writes data between ’top’ and ’base’ into ’base’.

Arguments:

job-id: string (optional)

identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

device: string

the device name or node-name of a root node

base: string (optional)

The file name of the backing image to write data into. If not specified, this is the deepest backing image.

top: string (optional)

The file name of the backing image within the image chain, which contains the topmost data to be committed down. If not specified, this is the active layer.

backing-file: string (optional)

The backing file string to write into the overlay image of ’top’. If ’top’ is the active layer, specifying a backing file string is an error. This filename is not validated.

If a pathname string is such that it cannot be resolved by QEMU, that means that subsequent QMP or HMP commands must use node-names for the image in question, as filename lookup methods will fail.

If not specified, QEMU will automatically determine the backing file string to use, or error out if there is no obvious choice. Care should be taken when specifying the string, to specify a valid filename or protocol. (Since 2.1)

If top == base, that is an error. If top == active, the job will not be completed by itself, user needs to complete the job with the block-job-complete command after getting the ready event. (Since 2.0)

If the base image is smaller than top, then the base image will be resized to be the same size as top. If top is smaller than the base image, the base will not be truncated. If you want the base image size to match the size of the smaller top, you can safely truncate it yourself once the commit operation successfully completes.

speed: int (optional)

the maximum speed, in bytes per second

filter-node-name: string (optional)

the node name that should be assigned to the filter driver that the commit job inserts into the graph above top. If this option is not given, a node name is autogenerated. (Since: 2.9)

Returns: Nothing on success If commit or stream is already active on this device, DeviceInUse If device does not exist, DeviceNotFound If image commit is not supported by this device, NotSupported If base or top is invalid, a generic error is returned If speed is invalid, InvalidParameter

Since: 1.3

Example:

-> { "execute": "block-commit",
     "arguments": { "device": "virtio0",
                    "top": "/tmp/snap1.qcow2" } }
<- { "return": {} }

Command: drive-backup ¶

Start a point-in-time copy of a block device to a new destination. The status of ongoing drive-backup operations can be checked with query-block-jobs where the BlockJobInfo.type field has the value ’backup’. The operation can be stopped before it has completed using the block-job-cancel command.

Arguments: the members of DriveBackup

Returns: nothing on success If device is not a valid block device, GenericError

Since: 1.6

Example:

-> { "execute": "drive-backup",
     "arguments": { "device": "drive0",
                    "sync": "full",
                    "target": "backup.img" } }
<- { "return": {} }

Command: blockdev-backup ¶

Start a point-in-time copy of a block device to a new destination. The status of ongoing blockdev-backup operations can be checked with query-block-jobs where the BlockJobInfo.type field has the value ’backup’. The operation can be stopped before it has completed using the block-job-cancel command.

Arguments: the members of BlockdevBackup

Returns: nothing on success If device is not a valid block device, DeviceNotFound

Since: 2.3

Example:

-> { "execute": "blockdev-backup",
     "arguments": { "device": "src-id",
                    "sync": "full",
                    "target": "tgt-id" } }
<- { "return": {} }

Command: query-named-block-nodes ¶

Get the named block driver list

Returns: the list of BlockDeviceInfo

Since: 2.0

Example:

-> { "execute": "query-named-block-nodes" }
<- { "return": [ { "ro":false,
                   "drv":"qcow2",
                   "encrypted":false,
                   "file":"disks/test.qcow2",
                   "node-name": "my-node",
                   "backing_file_depth":1,
                   "bps":1000000,
                   "bps_rd":0,
                   "bps_wr":0,
                   "iops":1000000,
                   "iops_rd":0,
                   "iops_wr":0,
                   "bps_max": 8000000,
                   "bps_rd_max": 0,
                   "bps_wr_max": 0,
                   "iops_max": 0,
                   "iops_rd_max": 0,
                   "iops_wr_max": 0,
                   "iops_size": 0,
                   "write_threshold": 0,
                   "image":{
                      "filename":"disks/test.qcow2",
                      "format":"qcow2",
                      "virtual-size":2048000,
                      "backing_file":"base.qcow2",
                      "full-backing-filename":"disks/base.qcow2",
                      "backing-filename-format":"qcow2",
                      "snapshots":[
                         {
                            "id": "1",
                            "name": "snapshot1",
                            "vm-state-size": 0,
                            "date-sec": 10000200,
                            "date-nsec": 12,
                            "vm-clock-sec": 206,
                            "vm-clock-nsec": 30
                         }
                      ],
                      "backing-image":{
                          "filename":"disks/base.qcow2",
                          "format":"qcow2",
                          "virtual-size":2048000
                      }
                   } } ] }

Command: drive-mirror ¶

Start mirroring a block device’s writes to a new destination. target specifies the target of the new image. If the file exists, or if it is a device, it will be used as the new destination for writes. If it does not exist, a new file will be created. format specifies the format of the mirror image, default is to probe if mode=’existing’, else the format of the source.

Arguments: the members of DriveMirror

Returns: nothing on success If device is not a valid block device, GenericError

Since: 1.3

Example:

-> { "execute": "drive-mirror",
     "arguments": { "device": "ide-hd0",
                    "target": "/some/place/my-image",
                    "sync": "full",
                    "format": "qcow2" } }
<- { "return": {} }

Object: DriveMirror ¶

A set of parameters describing drive mirror setup.

Members:

job-id: string (optional)

identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

device: string

the device name or node-name of a root node whose writes should be mirrored.

target: string

the target of the new image. If the file exists, or if it is a device, the existing file/device will be used as the new destination. If it does not exist, a new file will be created.

format: string (optional)

the format of the new destination, default is to probe if mode is ’existing’, else the format of the source

node-name: string (optional)

the new block driver state node name in the graph (Since 2.1)

replaces: string (optional)

with sync=full graph node name to be replaced by the new image when a whole image copy is done. This can be used to repair broken Quorum files. (Since 2.1)

mode: NewImageMode (optional)

whether and how QEMU should create a new image, default is ’absolute-paths’.

speed: int (optional)

the maximum speed, in bytes per second

sync: MirrorSyncMode

what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).

granularity: int (optional)

granularity of the dirty bitmap, default is 64K if the image format doesn’t have clusters, 4K if the clusters are smaller than that, else the cluster size. Must be a power of 2 between 512 and 64M (since 1.4).

buf-size: int (optional)

maximum amount of data in flight from source to target (since 1.4).

on-source-error: BlockdevOnError (optional)

the action to take on an error on the source, default ’report’. ’stop’ and ’enospc’ can only be used if the block device supports io-status (see BlockInfo).

on-target-error: BlockdevOnError (optional)

the action to take on an error on the target, default ’report’ (no limitations, since this applies to a different block device than device).

unmap: boolean (optional)

Whether to try to unmap target sectors where source has only zero. If true, and target unallocated sectors will read as zero, target image sectors will be unmapped; otherwise, zeroes will be written. Both will result in identical contents. Default is true. (Since 2.4)

Since: 1.3

Object: BlockDirtyBitmap ¶

Members:

node: string

name of device/node which the bitmap is tracking

name: string

name of the dirty bitmap

Since: 2.4

Object: BlockDirtyBitmapAdd ¶

Members:

node: string

name of device/node which the bitmap is tracking

name: string

name of the dirty bitmap

granularity: int (optional)

the bitmap granularity, default is 64k for block-dirty-bitmap-add

persistent: boolean (optional)

the bitmap is persistent, i.e. it will be saved to the corresponding block device image file on its close. For now only Qcow2 disks support persistent bitmaps. Default is false for block-dirty-bitmap-add. (Since: 2.10)

autoload: boolean (optional)

ignored and deprecated since 2.12. Currently, all dirty tracking bitmaps are loaded from Qcow2 on open.

Since: 2.4

Command: block-dirty-bitmap-add ¶

Create a dirty bitmap with a name on the node, and start tracking the writes.

Returns: nothing on success If node is not a valid block device or node, DeviceNotFound If name is already taken, GenericError with an explanation

Since: 2.4

Example:

-> { "execute": "block-dirty-bitmap-add",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

Command: block-dirty-bitmap-remove ¶

Stop write tracking and remove the dirty bitmap that was created with block-dirty-bitmap-add. If the bitmap is persistent, remove it from its storage too.

Returns: nothing on success If node is not a valid block device or node, DeviceNotFound If name is not found, GenericError with an explanation if name is frozen by an operation, GenericError

Since: 2.4

Example:

-> { "execute": "block-dirty-bitmap-remove",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

Command: block-dirty-bitmap-clear ¶

Clear (reset) a dirty bitmap on the device, so that an incremental backup from this point in time forward will only backup clusters modified after this clear operation.

Returns: nothing on success If node is not a valid block device, DeviceNotFound If name is not found, GenericError with an explanation

Since: 2.4

Example:

-> { "execute": "block-dirty-bitmap-clear",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

Object: BlockDirtyBitmapSha256 ¶

SHA256 hash of dirty bitmap data

Members:

sha256: string

ASCII representation of SHA256 bitmap hash

Since: 2.10

Command: x-debug-block-dirty-bitmap-sha256 ¶

Get bitmap SHA256

Returns: BlockDirtyBitmapSha256 on success If node is not a valid block device, DeviceNotFound If name is not found or if hashing has failed, GenericError with an explanation

Since: 2.10

Command: blockdev-mirror ¶

Start mirroring a block device’s writes to a new destination.

Arguments:

job-id: string (optional)

identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

device: string

The device name or node-name of a root node whose writes should be mirrored.

target: string

the id or node-name of the block device to mirror to. This mustn’t be attached to guest.

replaces: string (optional)

with sync=full graph node name to be replaced by the new image when a whole image copy is done. This can be used to repair broken Quorum files.

speed: int (optional)

the maximum speed, in bytes per second

sync: MirrorSyncMode

what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).

granularity: int (optional)

granularity of the dirty bitmap, default is 64K if the image format doesn’t have clusters, 4K if the clusters are smaller than that, else the cluster size. Must be a power of 2 between 512 and 64M

buf-size: int (optional)

maximum amount of data in flight from source to target

on-source-error: BlockdevOnError (optional)

the action to take on an error on the source, default ’report’. ’stop’ and ’enospc’ can only be used if the block device supports io-status (see BlockInfo).

on-target-error: BlockdevOnError (optional)

the action to take on an error on the target, default ’report’ (no limitations, since this applies to a different block device than device).

filter-node-name: string (optional)

the node name that should be assigned to the filter driver that the mirror job inserts into the graph above device. If this option is not given, a node name is autogenerated. (Since: 2.9)

Returns: nothing on success.

Since: 2.6

Example:

-> { "execute": "blockdev-mirror",
     "arguments": { "device": "ide-hd0",
                    "target": "target0",
                    "sync": "full" } }
<- { "return": {} }

Command: block_set_io_throttle ¶

Change I/O throttle limits for a block drive.

Since QEMU 2.4, each device with I/O limits is member of a throttle group.

If two or more devices are members of the same group, the limits will apply to the combined I/O of the whole group in a round-robin fashion. Therefore, setting new I/O limits to a device will affect the whole group.

The name of the group can be specified using the ’group’ parameter. If the parameter is unset, it is assumed to be the current group of that device. If it’s not in any group yet, the name of the device will be used as the name for its group.

The ’group’ parameter can also be used to move a device to a different group. In this case the limits specified in the parameters will be applied to the new group only.

I/O limits can be disabled by setting all of them to 0. In this case the device will be removed from its group and the rest of its members will not be affected. The ’group’ parameter is ignored.

Arguments: the members of BlockIOThrottle

Returns: Nothing on success If device is not a valid block device, DeviceNotFound

Since: 1.1

Example:

-> { "execute": "block_set_io_throttle",
     "arguments": { "id": "virtio-blk-pci0/virtio-backend",
                    "bps": 0,
                    "bps_rd": 0,
                    "bps_wr": 0,
                    "iops": 512,
                    "iops_rd": 0,
                    "iops_wr": 0,
                    "bps_max": 0,
                    "bps_rd_max": 0,
                    "bps_wr_max": 0,
                    "iops_max": 0,
                    "iops_rd_max": 0,
                    "iops_wr_max": 0,
                    "bps_max_length": 0,
                    "iops_size": 0 } }
<- { "return": {} }

-> { "execute": "block_set_io_throttle",
     "arguments": { "id": "ide0-1-0",
                    "bps": 1000000,
                    "bps_rd": 0,
                    "bps_wr": 0,
                    "iops": 0,
                    "iops_rd": 0,
                    "iops_wr": 0,
                    "bps_max": 8000000,
                    "bps_rd_max": 0,
                    "bps_wr_max": 0,
                    "iops_max": 0,
                    "iops_rd_max": 0,
                    "iops_wr_max": 0,
                    "bps_max_length": 60,
                    "iops_size": 0 } }
<- { "return": {} }

Object: BlockIOThrottle ¶

A set of parameters describing block throttling.

Members:

device: string (optional)

Block device name (deprecated, use id instead)

id: string (optional)

The name or QOM path of the guest device (since: 2.8)

bps: int

total throughput limit in bytes per second

bps_rd: int

read throughput limit in bytes per second

bps_wr: int

write throughput limit in bytes per second

iops: int

total I/O operations per second

iops_rd: int

read I/O operations per second

iops_wr: int

write I/O operations per second

bps_max: int (optional)

total throughput limit during bursts, in bytes (Since 1.7)

bps_rd_max: int (optional)

read throughput limit during bursts, in bytes (Since 1.7)

bps_wr_max: int (optional)

write throughput limit during bursts, in bytes (Since 1.7)

iops_max: int (optional)

total I/O operations per second during bursts, in bytes (Since 1.7)

iops_rd_max: int (optional)

read I/O operations per second during bursts, in bytes (Since 1.7)

iops_wr_max: int (optional)

write I/O operations per second during bursts, in bytes (Since 1.7)

bps_max_length: int (optional)

maximum length of the bps_max burst period, in seconds. It must only be set if bps_max is set as well. Defaults to 1. (Since 2.6)

bps_rd_max_length: int (optional)

maximum length of the bps_rd_max burst period, in seconds. It must only be set if bps_rd_max is set as well. Defaults to 1. (Since 2.6)

bps_wr_max_length: int (optional)

maximum length of the bps_wr_max burst period, in seconds. It must only be set if bps_wr_max is set as well. Defaults to 1. (Since 2.6)

iops_max_length: int (optional)

maximum length of the iops burst period, in seconds. It must only be set if iops_max is set as well. Defaults to 1. (Since 2.6)

iops_rd_max_length: int (optional)

maximum length of the iops_rd_max burst period, in seconds. It must only be set if iops_rd_max is set as well. Defaults to 1. (Since 2.6)

iops_wr_max_length: int (optional)

maximum length of the iops_wr_max burst period, in seconds. It must only be set if iops_wr_max is set as well. Defaults to 1. (Since 2.6)

iops_size: int (optional)

an I/O size in bytes (Since 1.7)

group: string (optional)

throttle group name (Since 2.4)

Since: 1.1

Object: ThrottleLimits ¶

Limit parameters for throttling. Since some limit combinations are illegal, limits should always be set in one transaction. All fields are optional. When setting limits, if a field is missing the current value is not changed.

Members:

iops-total: int (optional)

limit total I/O operations per second

iops-total-max: int (optional)

I/O operations burst

iops-total-max-length: int (optional)

length of the iops-total-max burst period, in seconds It must only be set if iops-total-max is set as well.

iops-read: int (optional)

limit read operations per second

iops-read-max: int (optional)

I/O operations read burst

iops-read-max-length: int (optional)

length of the iops-read-max burst period, in seconds It must only be set if iops-read-max is set as well.

iops-write: int (optional)

limit write operations per second

iops-write-max: int (optional)

I/O operations write burst

iops-write-max-length: int (optional)

length of the iops-write-max burst period, in seconds It must only be set if iops-write-max is set as well.

bps-total: int (optional)

limit total bytes per second

bps-total-max: int (optional)

total bytes burst

bps-total-max-length: int (optional)

length of the bps-total-max burst period, in seconds. It must only be set if bps-total-max is set as well.

bps-read: int (optional)

limit read bytes per second

bps-read-max: int (optional)

total bytes read burst

bps-read-max-length: int (optional)

length of the bps-read-max burst period, in seconds It must only be set if bps-read-max is set as well.

bps-write: int (optional)

limit write bytes per second

bps-write-max: int (optional)

total bytes write burst

bps-write-max-length: int (optional)

length of the bps-write-max burst period, in seconds It must only be set if bps-write-max is set as well.

iops-size: int (optional)

when limiting by iops max size of an I/O in bytes

Since: 2.11

Command: block-stream ¶

Copy data from a backing file into a block device.

The block streaming operation is performed in the background until the entire backing file has been copied. This command returns immediately once streaming has started. The status of ongoing block streaming operations can be checked with query-block-jobs. The operation can be stopped before it has completed using the block-job-cancel command.

The node that receives the data is called the top image, can be located in any part of the chain (but always above the base image; see below) and can be specified using its device or node name. Earlier qemu versions only allowed ’device’ to name the top level node; presence of the ’base-node’ parameter during introspection can be used as a witness of the enhanced semantics of ’device’.

If a base file is specified then sectors are not copied from that base file and its backing chain. When streaming completes the image file will have the base file as its backing file. This can be used to stream a subset of the backing file chain instead of flattening the entire image.

On successful completion the image file is updated to drop the backing file and the BLOCK_JOB_COMPLETED event is emitted.

Arguments:

job-id: string (optional)

identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)

device: string

the device or node name of the top image

base: string (optional)

the common backing file name. It cannot be set if base-node is also set.

base-node: string (optional)

the node name of the backing file. It cannot be set if base is also set. (Since 2.8)

backing-file: string (optional)

The backing file string to write into the top image. This filename is not validated.

If a pathname string is such that it cannot be resolved by QEMU, that means that subsequent QMP or HMP commands must use node-names for the image in question, as filename lookup methods will fail.

If not specified, QEMU will automatically determine the backing file string to use, or error out if there is no obvious choice. Care should be taken when specifying the string, to specify a valid filename or protocol. (Since 2.1)

speed: int (optional)

the maximum speed, in bytes per second

on-error: BlockdevOnError (optional)

the action to take on an error (default report). ’stop’ and ’enospc’ can only be used if the block device supports io-status (see BlockInfo). Since 1.3.

Returns: Nothing on success. If device does not exist, DeviceNotFound.

Since: 1.1

Example:

-> { "execute": "block-stream",
     "arguments": { "device": "virtio0",
                    "base": "/tmp/master.qcow2" } }
<- { "return": {} }

Command: block-job-set-speed ¶

Set maximum speed for a background block operation.

This command can only be issued when there is an active block job.

Throttling can be disabled by setting the speed to 0.

Arguments:

device: string

The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

speed: int

the maximum speed, in bytes per second, or 0 for unlimited. Defaults to 0.

Returns: Nothing on success If no background operation is active on this device, DeviceNotActive

Since: 1.1

Command: block-job-cancel ¶

Stop an active background block operation.

This command returns immediately after marking the active background block operation for cancellation. It is an error to call this command if no operation is in progress.

The operation will cancel as soon as possible and then emit the BLOCK_JOB_CANCELLED event. Before that happens the job is still visible when enumerated using query-block-jobs.

Note that if you issue ’block-job-cancel’ after ’drive-mirror’ has indicated (via the event BLOCK_JOB_READY) that the source and destination are synchronized, then the event triggered by this command changes to BLOCK_JOB_COMPLETED, to indicate that the mirroring has ended and the destination now has a point-in-time copy tied to the time of the cancellation.

For streaming, the image file retains its backing file unless the streaming operation happens to complete just as it is being cancelled. A new streaming operation can be started at a later time to finish copying all data from the backing file.

Arguments:

device: string

The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

force: boolean (optional)

If true, and the job has already emitted the event BLOCK_JOB_READY, abandon the job immediately (even if it is paused) instead of waiting for the destination to complete its final synchronization (since 1.3)

Returns: Nothing on success If no background operation is active on this device, DeviceNotActive

Since: 1.1

Command: block-job-pause ¶

Pause an active background block operation.

This command returns immediately after marking the active background block operation for pausing. It is an error to call this command if no operation is in progress. Pausing an already paused job has no cumulative effect; a single block-job-resume command will resume the job.

The operation will pause as soon as possible. No event is emitted when the operation is actually paused. Cancelling a paused job automatically resumes it.

Arguments:

device: string

The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

Returns: Nothing on success If no background operation is active on this device, DeviceNotActive

Since: 1.3

Command: block-job-resume ¶

Resume an active background block operation.

This command returns immediately after resuming a paused background block operation. It is an error to call this command if no operation is in progress. Resuming an already running job is not an error.

This command also clears the error status of the job.

Arguments:

device: string

The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

Returns: Nothing on success If no background operation is active on this device, DeviceNotActive

Since: 1.3

Command: block-job-complete ¶

Manually trigger completion of an active background block operation. This is supported for drive mirroring, where it also switches the device to write to the target path only. The ability to complete is signaled with a BLOCK_JOB_READY event.

This command completes an active background block operation synchronously. The ordering of this command’s return with the BLOCK_JOB_COMPLETED event is not defined. Note that if an I/O error occurs during the processing of this command: 1) the command itself will fail; 2) the error will be processed according to the rerror/werror arguments that were specified when starting the operation.

A cancelled or paused job cannot be completed.

Arguments:

device: string

The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

Returns: Nothing on success If no background operation is active on this device, DeviceNotActive

Since: 1.3

Command: block-job-dismiss ¶

For jobs that have already concluded, remove them from the block-job-query list. This command only needs to be run for jobs which were started with QEMU 2.12+ job lifetime management semantics.

This command will refuse to operate on any job that has not yet reached its terminal state, BLOCK_JOB_STATUS_CONCLUDED. For jobs that make use of BLOCK_JOB_READY event, block-job-cancel or block-job-complete will still need to be used as appropriate.

Arguments:

id: string

The job identifier.

Returns: Nothing on success

Since: 2.12

Command: block-job-finalize ¶

Once a job that has manual=true reaches the pending state, it can be instructed to finalize any graph changes and do any necessary cleanup via this command. For jobs in a transaction, instructing one job to finalize will force ALL jobs in the transaction to finalize, so it is only necessary to instruct a single member job to finalize.

Arguments:

id: string

The job identifier.

Returns: Nothing on success

Since: 2.12

Enum: BlockdevDiscardOptions ¶

Determines how to handle discard requests.

Values:

ignore

Ignore the request

unmap

Forward as an unmap request

Since: 2.9

Enum: BlockdevDetectZeroesOptions ¶

Describes the operation mode for the automatic conversion of plain zero writes by the OS to driver specific optimized zero write commands.

Values:

off

Disabled (default)

on

Enabled

unmap

Enabled and even try to unmap blocks if possible. This requires also that BlockdevDiscardOptions is set to unmap for this device.

Since: 2.1

Enum: BlockdevAioOptions ¶

Selects the AIO backend to handle I/O requests

Values:

threads

Use qemu’s thread pool

native

Use native AIO backend (only Linux and Windows)

Since: 2.9

Object: BlockdevCacheOptions ¶

Includes cache-related options for block devices

Members:

direct: boolean (optional)

enables use of O_DIRECT (bypass the host page cache; default: false)

no-flush: boolean (optional)

ignore any flush requests for the device (default: false)

Since: 2.9

Enum: BlockdevDriver ¶

Drivers that are supported in block device operations.

Values:

vxhs

Since 2.10

throttle

Since 2.11

nvme

Since 2.12

blkdebug

Not documented

blkverify

Not documented

bochs

Not documented

cloop

Not documented

dmg

Not documented

file

Not documented

ftp

Not documented

ftps

Not documented

gluster

Not documented

host_cdrom

Not documented

host_device

Not documented

http

Not documented

https

Not documented

iscsi

Not documented

luks

Not documented

nbd

Not documented

nfs

Not documented

null-aio

Not documented

null-co

Not documented

parallels

Not documented

qcow

Not documented

qcow2

Not documented

qed

Not documented

quorum

Not documented

raw

Not documented

rbd

Not documented

replication

Not documented

sheepdog

Not documented

ssh

Not documented

vdi

Not documented

vhdx

Not documented

vmdk

Not documented

vpc

Not documented

vvfat

Not documented

Since: 2.9

Object: BlockdevOptionsFile ¶

Driver specific block device options for the file backend.

Members:

filename: string

path to the image file

pr-manager: string (optional)

the id for the object that will handle persistent reservations for this device (default: none, forward the commands via SG_IO; since 2.11)

aio: BlockdevAioOptions (optional)

AIO backend (default: threads) (since: 2.8)

locking: OnOffAuto (optional)

whether to enable file locking. If set to ’auto’, only enable when Open File Descriptor (OFD) locking API is available (default: auto, since 2.10)

Since: 2.9

Object: BlockdevOptionsNull ¶

Driver specific block device options for the null backend.

Members:

size: int (optional)

size of the device in bytes.

latency-ns: int (optional)

emulated latency (in nanoseconds) in processing requests. Default to zero which completes requests immediately. (Since 2.4)

Since: 2.9

Object: BlockdevOptionsNVMe ¶

Driver specific block device options for the NVMe backend.

Members:

device: string

controller address of the NVMe device.

namespace: int

namespace number of the device, starting from 1.

Since: 2.12

Object: BlockdevOptionsVVFAT ¶

Driver specific block device options for the vvfat protocol.

Members:

dir: string

directory to be exported as FAT image

fat-type: int (optional)

FAT type: 12, 16 or 32

floppy: boolean (optional)

whether to export a floppy image (true) or partitioned hard disk (false; default)

label: string (optional)

set the volume label, limited to 11 bytes. FAT16 and FAT32 traditionally have some restrictions on labels, which are ignored by most operating systems. Defaults to "QEMU VVFAT". (since 2.4)

rw: boolean (optional)

whether to allow write operations (default: false)

Since: 2.9

Object: BlockdevOptionsGenericFormat ¶

Driver specific block device options for image format that have no option besides their data source.

Members:

file: BlockdevRef

reference to or definition of the data source block device

Since: 2.9

Object: BlockdevOptionsLUKS ¶

Driver specific block device options for LUKS.

Members:

key-secret: string (optional)

the ID of a QCryptoSecret object providing the decryption key (since 2.6). Mandatory except when doing a metadata-only probe of the image.

The members of BlockdevOptionsGenericFormat

Since: 2.9

Object: BlockdevOptionsGenericCOWFormat ¶

Driver specific block device options for image format that have no option besides their data source and an optional backing file.

Members:

backing: BlockdevRefOrNull (optional)

reference to or definition of the backing file block device, null disables the backing file entirely. Defaults to the backing file stored the image file.

The members of BlockdevOptionsGenericFormat

Since: 2.9

Enum: Qcow2OverlapCheckMode ¶

General overlap check modes.

Values:

none

Do not perform any checks

constant

Perform only checks which can be done in constant time and without reading anything from disk

cached

Perform only checks which can be done without reading anything from disk

all

Perform all available overlap checks

Since: 2.9

Object: Qcow2OverlapCheckFlags ¶

Structure of flags for each metadata structure. Setting a field to ’true’ makes qemu guard that structure against unintended overwriting. The default value is chosen according to the template given.

Members:

template: Qcow2OverlapCheckMode (optional)

Specifies a template mode which can be adjusted using the other flags, defaults to ’cached’

main-header: boolean (optional)

Not documented

active-l1: boolean (optional)

Not documented

active-l2: boolean (optional)

Not documented

refcount-table: boolean (optional)

Not documented

refcount-block: boolean (optional)

Not documented

snapshot-table: boolean (optional)

Not documented

inactive-l1: boolean (optional)

Not documented

inactive-l2: boolean (optional)

Not documented

Since: 2.9

Alternate: Qcow2OverlapChecks ¶

Specifies which metadata structures should be guarded against unintended overwriting.

Members:

flags: Qcow2OverlapCheckFlags

set of flags for separate specification of each metadata structure type

mode: Qcow2OverlapCheckMode

named mode which chooses a specific set of flags

Since: 2.9

Enum: BlockdevQcowEncryptionFormat ¶

Values:

aes

AES-CBC with plain64 initialization vectors

Since: 2.10

Object: BlockdevQcowEncryption ¶

Members:

format: BlockdevQcowEncryptionFormat

Not documented

The members of QCryptoBlockOptionsQCow when format is "aes"

Since: 2.10

Object: BlockdevOptionsQcow ¶

Driver specific block device options for qcow.

Members:

encrypt: BlockdevQcowEncryption (optional)

Image decryption options. Mandatory for encrypted images, except when doing a metadata-only probe of the image.

The members of BlockdevOptionsGenericCOWFormat

Since: 2.10

Enum: BlockdevQcow2EncryptionFormat ¶

Values:

aes

AES-CBC with plain64 initialization venctors

luks

Not documented

Since: 2.10

Object: BlockdevQcow2Encryption ¶

Members:

format: BlockdevQcow2EncryptionFormat

Not documented

The members of QCryptoBlockOptionsQCow when format is "aes"

The members of QCryptoBlockOptionsLUKS when format is "luks"

Since: 2.10

Object: BlockdevOptionsQcow2 ¶

Driver specific block device options for qcow2.

Members:

lazy-refcounts: boolean (optional)

whether to enable the lazy refcounts feature (default is taken from the image file)

pass-discard-request: boolean (optional)

whether discard requests to the qcow2 device should be forwarded to the data source

pass-discard-snapshot: boolean (optional)

whether discard requests for the data source should be issued when a snapshot operation (e.g. deleting a snapshot) frees clusters in the qcow2 file

pass-discard-other: boolean (optional)

whether discard requests for the data source should be issued on other occasions where a cluster gets freed

overlap-check: Qcow2OverlapChecks (optional)

which overlap checks to perform for writes to the image, defaults to ’cached’ (since 2.2)

cache-size: int (optional)

the maximum total size of the L2 table and refcount block caches in bytes (since 2.2)

l2-cache-size: int (optional)

the maximum size of the L2 table cache in bytes (since 2.2)

l2-cache-entry-size: int (optional)

the size of each entry in the L2 cache in bytes. It must be a power of two between 512 and the cluster size. The default value is the cluster size (since 2.12)

refcount-cache-size: int (optional)

the maximum size of the refcount block cache in bytes (since 2.2)

cache-clean-interval: int (optional)

clean unused entries in the L2 and refcount caches. The interval is in seconds. The default value is 0 and it disables this feature (since 2.5)

encrypt: BlockdevQcow2Encryption (optional)

Image decryption options. Mandatory for encrypted images, except when doing a metadata-only probe of the image. (since 2.10)

The members of BlockdevOptionsGenericCOWFormat

Since: 2.9

Enum: SshHostKeyCheckMode ¶

none Don’t check the host key at all hash Compare the host key with a given hash known_hosts Check the host key against the known_hosts file

Values:

none

Not documented

hash

Not documented

known_hosts

Not documented

Since: 2.12

Enum: SshHostKeyCheckHashType ¶

md5 The given hash is an md5 hash sha1 The given hash is an sha1 hash

Values:

md5

Not documented

sha1

Not documented

Since: 2.12

Object: SshHostKeyHash ¶

type The hash algorithm used for the hash hash The expected hash value

Members:

type: SshHostKeyCheckHashType

Not documented

hash: string

Not documented

Since: 2.12

Object: SshHostKeyDummy ¶

For those union branches that don’t need additional fields.

Since: 2.12

Object: SshHostKeyCheck ¶

Members:

mode: SshHostKeyCheckMode

Not documented

The members of SshHostKeyDummy when mode is "none"

The members of SshHostKeyHash when mode is "hash"

The members of SshHostKeyDummy when mode is "known_hosts"

Since: 2.12

Object: BlockdevOptionsSsh ¶

Members:

server: InetSocketAddress

host address

path: string

path to the image on the host

user: string (optional)

user as which to connect, defaults to current local user name

host-key-check: SshHostKeyCheck (optional)

Defines how and what to check the host key against (default: known_hosts)

Since: 2.9

Enum: BlkdebugEvent ¶

Trigger events supported by blkdebug.

Values:

l1_shrink_write_table

write zeros to the l1 table to shrink image. (since 2.11)

l1_shrink_free_l2_clusters

discard the l2 tables. (since 2.11)

cor_write

a write due to copy-on-read (since 2.11)

l1_update

Not documented

l1_grow_alloc_table

Not documented

l1_grow_write_table

Not documented

l1_grow_activate_table

Not documented

l2_load

Not documented

l2_update

Not documented

l2_update_compressed

Not documented

l2_alloc_cow_read

Not documented

l2_alloc_write

Not documented

read_aio

Not documented

read_backing_aio

Not documented

read_compressed

Not documented

write_aio

Not documented

write_compressed

Not documented

vmstate_load

Not documented

vmstate_save

Not documented

cow_read

Not documented

cow_write

Not documented

reftable_load

Not documented

reftable_grow

Not documented

reftable_update

Not documented

refblock_load

Not documented

refblock_update

Not documented

refblock_update_part

Not documented

refblock_alloc

Not documented

refblock_alloc_hookup

Not documented

refblock_alloc_write

Not documented

refblock_alloc_write_blocks

Not documented

refblock_alloc_write_table

Not documented

refblock_alloc_switch_table

Not documented

cluster_alloc

Not documented

cluster_alloc_bytes

Not documented

cluster_free

Not documented

flush_to_os

Not documented

flush_to_disk

Not documented

pwritev_rmw_head

Not documented

pwritev_rmw_after_head

Not documented

pwritev_rmw_tail

Not documented

pwritev_rmw_after_tail

Not documented

pwritev

Not documented

pwritev_zero

Not documented

pwritev_done

Not documented

empty_image_prepare

Not documented

Since: 2.9

Object: BlkdebugInjectErrorOptions ¶

Describes a single error injection for blkdebug.

Members:

event: BlkdebugEvent

trigger event

state: int (optional)

the state identifier blkdebug needs to be in to actually trigger the event; defaults to "any"

errno: int (optional)

error identifier (errno) to be returned; defaults to EIO

sector: int (optional)

specifies the sector index which has to be affected in order to actually trigger the event; defaults to "any sector"

once: boolean (optional)

disables further events after this one has been triggered; defaults to false

immediately: boolean (optional)

fail immediately; defaults to false

Since: 2.9

Object: BlkdebugSetStateOptions ¶

Describes a single state-change event for blkdebug.

Members:

event: BlkdebugEvent

trigger event

state: int (optional)

the current state identifier blkdebug needs to be in; defaults to "any"

new_state: int

the state identifier blkdebug is supposed to assume if this event is triggered

Since: 2.9

Object: BlockdevOptionsBlkdebug ¶

Driver specific block device options for blkdebug.

Members:

image: BlockdevRef

underlying raw block device (or image file)

config: string (optional)

filename of the configuration file

align: int (optional)

required alignment for requests in bytes, must be positive power of 2, or 0 for default

max-transfer: int (optional)

maximum size for I/O transfers in bytes, must be positive multiple of align and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)

opt-write-zero: int (optional)

preferred alignment for write zero requests in bytes, must be positive multiple of align and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)

max-write-zero: int (optional)

maximum size for write zero requests in bytes, must be positive multiple of align, of opt-write-zero, and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)

opt-discard: int (optional)

preferred alignment for discard requests in bytes, must be positive multiple of align and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)

max-discard: int (optional)

maximum size for discard requests in bytes, must be positive multiple of align, of opt-discard, and of the underlying file’s request alignment (but need not be a power of 2), or 0 for default (since 2.10)

inject-error: array of BlkdebugInjectErrorOptions (optional)

array of error injection descriptions

set-state: array of BlkdebugSetStateOptions (optional)

array of state-change descriptions

Since: 2.9

Object: BlockdevOptionsBlkverify ¶

Driver specific block device options for blkverify.

Members:

test: BlockdevRef

block device to be tested

raw: BlockdevRef

raw image used for verification

Since: 2.9

Enum: QuorumReadPattern ¶

An enumeration of quorum read patterns.

Values:

quorum

read all the children and do a quorum vote on reads

fifo

read only from the first child that has not failed

Since: 2.9

Object: BlockdevOptionsQuorum ¶

Driver specific block device options for Quorum

Members:

blkverify: boolean (optional)

true if the driver must print content mismatch set to false by default

children: array of BlockdevRef

the children block devices to use

vote-threshold: int

the vote limit under which a read will fail

rewrite-corrupted: boolean (optional)

rewrite corrupted data when quorum is reached (Since 2.1)

read-pattern: QuorumReadPattern (optional)

choose read pattern and set to quorum by default (Since 2.2)

Since: 2.9

Object: BlockdevOptionsGluster ¶

Driver specific block device options for Gluster

Members:

volume: string

name of gluster volume where VM image resides

path: string

absolute path to image file in gluster volume

server: array of SocketAddress

gluster servers description

debug: int (optional)

libgfapi log level (default ’4’ which is Error) (Since 2.8)

logfile: string (optional)

libgfapi log file (default /dev/stderr) (Since 2.8)

Since: 2.9

Enum: IscsiTransport ¶

An enumeration of libiscsi transport types

Values:

tcp

Not documented

iser

Not documented

Since: 2.9

Enum: IscsiHeaderDigest ¶

An enumeration of header digests supported by libiscsi

Values:

crc32c

Not documented

none

Not documented

crc32c-none

Not documented

none-crc32c

Not documented

Since: 2.9

Object: BlockdevOptionsIscsi ¶

Members:

transport: IscsiTransport

The iscsi transport type

portal: string

The address of the iscsi portal

target: string

The target iqn name

lun: int (optional)

LUN to connect to. Defaults to 0.

user: string (optional)

User name to log in with. If omitted, no CHAP authentication is performed.

password-secret: string (optional)

The ID of a QCryptoSecret object providing the password for the login. This option is required if user is specified.

initiator-name: string (optional)

The iqn name we want to identify to the target as. If this option is not specified, an initiator name is generated automatically.

header-digest: IscsiHeaderDigest (optional)

The desired header digest. Defaults to none-crc32c.

timeout: int (optional)

Timeout in seconds after which a request will timeout. 0 means no timeout and is the default.

Driver specific block device options for iscsi

Since: 2.9

Object: BlockdevOptionsRbd ¶

Members:

pool: string

Ceph pool name.

image: string

Image name in the Ceph pool.

conf: string (optional)

path to Ceph configuration file. Values in the configuration file will be overridden by options specified via QAPI.

snapshot: string (optional)

Ceph snapshot name.

user: string (optional)

Ceph id name.

server: array of InetSocketAddressBase (optional)

Monitor host address and port. This maps to the "mon_host" Ceph option.

Since: 2.9

Object: BlockdevOptionsSheepdog ¶

Driver specific block device options for sheepdog

Members:

vdi: string

Virtual disk image name

server: SocketAddress

The Sheepdog server to connect to

snap-id: int (optional)

Snapshot ID

tag: string (optional)

Snapshot tag name

Only one of snap-id and tag may be present.

Since: 2.9

Enum: ReplicationMode ¶

An enumeration of replication modes.

Values:

primary

Primary mode, the vm’s state will be sent to secondary QEMU.

secondary

Secondary mode, receive the vm’s state from primary QEMU.

Since: 2.9

Object: BlockdevOptionsReplication ¶

Driver specific block device options for replication

Members:

mode: ReplicationMode

the replication mode

top-id: string (optional)

In secondary mode, node name or device ID of the root node who owns the replication node chain. Must not be given in primary mode.

The members of BlockdevOptionsGenericFormat

Since: 2.9

Enum: NFSTransport ¶

An enumeration of NFS transport types

Values:

inet

TCP transport

Since: 2.9

Object: NFSServer ¶

Captures the address of the socket

Members:

type: NFSTransport

transport type used for NFS (only TCP supported)

host: string

host address for NFS server

Since: 2.9

Object: BlockdevOptionsNfs ¶

Driver specific block device option for NFS

Members:

server: NFSServer

host address

path: string

path of the image on the host

user: int (optional)

UID value to use when talking to the server (defaults to 65534 on Windows and getuid() on unix)

group: int (optional)

GID value to use when talking to the server (defaults to 65534 on Windows and getgid() in unix)

tcp-syn-count: int (optional)

number of SYNs during the session establishment (defaults to libnfs default)

readahead-size: int (optional)

set the readahead size in bytes (defaults to libnfs default)

page-cache-size: int (optional)

set the pagecache size in bytes (defaults to libnfs default)

debug: int (optional)

set the NFS debug level (max 2) (defaults to libnfs default)

Since: 2.9

Object: BlockdevOptionsCurlBase ¶

Driver specific block device options shared by all protocols supported by the curl backend.

Members:

url: string

URL of the image file

readahead: int (optional)

Size of the read-ahead cache; must be a multiple of 512 (defaults to 256 kB)

timeout: int (optional)

Timeout for connections, in seconds (defaults to 5)

username: string (optional)

Username for authentication (defaults to none)

password-secret: string (optional)

ID of a QCryptoSecret object providing a password for authentication (defaults to no password)

proxy-username: string (optional)

Username for proxy authentication (defaults to none)

proxy-password-secret: string (optional)

ID of a QCryptoSecret object providing a password for proxy authentication (defaults to no password)

Since: 2.9

Object: BlockdevOptionsCurlHttp ¶

Driver specific block device options for HTTP connections over the curl backend. URLs must start with "http://".

Members:

cookie: string (optional)

List of cookies to set; format is "name1=content1; name2=content2;" as explained by CURLOPT_COOKIE(3). Defaults to no cookies.

cookie-secret: string (optional)

ID of a QCryptoSecret object providing the cookie data in a secure way. See cookie for the format. (since 2.10)

The members of BlockdevOptionsCurlBase

Since: 2.9

Object: BlockdevOptionsCurlHttps ¶

Driver specific block device options for HTTPS connections over the curl backend. URLs must start with "https://".

Members:

cookie: string (optional)

List of cookies to set; format is "name1=content1; name2=content2;" as explained by CURLOPT_COOKIE(3). Defaults to no cookies.

sslverify: boolean (optional)

Whether to verify the SSL certificate’s validity (defaults to true)

cookie-secret: string (optional)

ID of a QCryptoSecret object providing the cookie data in a secure way. See cookie for the format. (since 2.10)

The members of BlockdevOptionsCurlBase

Since: 2.9

Object: BlockdevOptionsCurlFtp ¶

Driver specific block device options for FTP connections over the curl backend. URLs must start with "ftp://".

Members:

The members of BlockdevOptionsCurlBase

Since: 2.9

Object: BlockdevOptionsCurlFtps ¶

Driver specific block device options for FTPS connections over the curl backend. URLs must start with "ftps://".

Members:

sslverify: boolean (optional)

Whether to verify the SSL certificate’s validity (defaults to true)

The members of BlockdevOptionsCurlBase

Since: 2.9

Object: BlockdevOptionsNbd ¶

Driver specific block device options for NBD.

Members:

server: SocketAddress

NBD server address

export: string (optional)

export name

tls-creds: string (optional)

TLS credentials ID

Since: 2.9

Object: BlockdevOptionsRaw ¶

Driver specific block device options for the raw driver.

Members:

offset: int (optional)

position where the block device starts

size: int (optional)

the assumed size of the device

The members of BlockdevOptionsGenericFormat

Since: 2.9

Object: BlockdevOptionsVxHS ¶

Driver specific block device options for VxHS

Members:

vdisk-id: string

UUID of VxHS volume

server: InetSocketAddressBase

vxhs server IP, port

tls-creds: string (optional)

TLS credentials ID

Since: 2.10

Object: BlockdevOptionsThrottle ¶

Driver specific block device options for the throttle driver

Members:

throttle-group: string

the name of the throttle-group object to use. It must already exist.

file: BlockdevRef

reference to or definition of the data source block device

Since: 2.11

Object: BlockdevOptions ¶

Options for creating a block device. Many options are available for all block devices, independent of the block driver:

Members:

driver: BlockdevDriver

block driver name

node-name: string (optional)

the node name of the new node (Since 2.0). This option is required on the top level of blockdev-add.

discard: BlockdevDiscardOptions (optional)

discard-related options (default: ignore)

cache: BlockdevCacheOptions (optional)

cache-related options

read-only: boolean (optional)

whether the block device should be read-only (default: false). Note that some block drivers support only read-only access, either generally or in certain configurations. In this case, the default value does not work and the option must be specified explicitly.

detect-zeroes: BlockdevDetectZeroesOptions (optional)

detect and optimize zero writes (Since 2.1) (default: off)

force-share: boolean (optional)

force share all permission on added nodes. Requires read-only=true. (Since 2.10)

The members of BlockdevOptionsBlkdebug when driver is "blkdebug"

The members of BlockdevOptionsBlkverify when driver is "blkverify"

The members of BlockdevOptionsGenericFormat when driver is "bochs"

The members of BlockdevOptionsGenericFormat when driver is "cloop"

The members of BlockdevOptionsGenericFormat when driver is "dmg"

The members of BlockdevOptionsFile when driver is "file"

The members of BlockdevOptionsCurlFtp when driver is "ftp"

The members of BlockdevOptionsCurlFtps when driver is "ftps"

The members of BlockdevOptionsGluster when driver is "gluster"

The members of BlockdevOptionsFile when driver is "host_cdrom"

The members of BlockdevOptionsFile when driver is "host_device"

The members of BlockdevOptionsCurlHttp when driver is "http"

The members of BlockdevOptionsCurlHttps when driver is "https"

The members of BlockdevOptionsIscsi when driver is "iscsi"

The members of BlockdevOptionsLUKS when driver is "luks"

The members of BlockdevOptionsNbd when driver is "nbd"

The members of BlockdevOptionsNfs when driver is "nfs"

The members of BlockdevOptionsNull when driver is "null-aio"

The members of BlockdevOptionsNull when driver is "null-co"

The members of BlockdevOptionsNVMe when driver is "nvme"

The members of BlockdevOptionsGenericFormat when driver is "parallels"

The members of BlockdevOptionsQcow2 when driver is "qcow2"

The members of BlockdevOptionsQcow when driver is "qcow"

The members of BlockdevOptionsGenericCOWFormat when driver is "qed"

The members of BlockdevOptionsQuorum when driver is "quorum"

The members of BlockdevOptionsRaw when driver is "raw"

The members of BlockdevOptionsRbd when driver is "rbd"

The members of BlockdevOptionsReplication when driver is "replication"

The members of BlockdevOptionsSheepdog when driver is "sheepdog"

The members of BlockdevOptionsSsh when driver is "ssh"

The members of BlockdevOptionsThrottle when driver is "throttle"

The members of BlockdevOptionsGenericFormat when driver is "vdi"

The members of BlockdevOptionsGenericFormat when driver is "vhdx"

The members of BlockdevOptionsGenericCOWFormat when driver is "vmdk"

The members of BlockdevOptionsGenericFormat when driver is "vpc"

The members of BlockdevOptionsVVFAT when driver is "vvfat"

The members of BlockdevOptionsVxHS when driver is "vxhs"

Remaining options are determined by the block driver.

Since: 2.9

Alternate: BlockdevRef ¶

Reference to a block device.

Members:

definition: BlockdevOptions

defines a new block device inline

reference: string

references the ID of an existing block device

Since: 2.9

Alternate: BlockdevRefOrNull ¶

Reference to a block device.

Members:

definition: BlockdevOptions

defines a new block device inline

reference: string

references the ID of an existing block device. An empty string means that no block device should be referenced. Deprecated; use null instead.

null: null

No block device should be referenced (since 2.10)

Since: 2.9

Command: blockdev-add ¶

Creates a new block device. If the id option is given at the top level, a BlockBackend will be created; otherwise, node-name is mandatory at the top level and no BlockBackend will be created.

Arguments: the members of BlockdevOptions

Since: 2.9

Example:

1.
-> { "execute": "blockdev-add",
     "arguments": {
          "driver": "qcow2",
          "node-name": "test1",
          "file": {
              "driver": "file",
              "filename": "test.qcow2"
           }
      }
    }
<- { "return": {} }

2.
-> { "execute": "blockdev-add",
     "arguments": {
          "driver": "qcow2",
          "node-name": "node0",
          "discard": "unmap",
          "cache": {
             "direct": true
           },
           "file": {
             "driver": "file",
             "filename": "/tmp/test.qcow2"
           },
           "backing": {
              "driver": "raw",
              "file": {
                 "driver": "file",
                 "filename": "/dev/fdset/4"
               }
           }
       }
     }

<- { "return": {} }

Command: blockdev-del ¶

Deletes a block device that has been added using blockdev-add. The command will fail if the node is attached to a device or is otherwise being used.

Arguments:

node-name: string

Name of the graph node to delete.

Since: 2.9

Example:

-> { "execute": "blockdev-add",
     "arguments": {
          "driver": "qcow2",
          "node-name": "node0",
          "file": {
              "driver": "file",
              "filename": "test.qcow2"
          }
     }
   }
<- { "return": {} }

-> { "execute": "blockdev-del",
     "arguments": { "node-name": "node0" }
   }
<- { "return": {} }

Object: BlockdevCreateOptionsFile ¶

Driver specific image creation options for file.

filename Filename for the new image file size Size of the virtual disk in bytes preallocation Preallocation mode for the new image (default: off) nocow Turn off copy-on-write (valid only on btrfs; default: off)

Members:

filename: string

Not documented

size: int

Not documented

preallocation: PreallocMode (optional)

Not documented

nocow: boolean (optional)

Not documented

Since: 2.12

Object: BlockdevCreateOptionsGluster ¶

Driver specific image creation options for gluster.

location Where to store the new image file size Size of the virtual disk in bytes preallocation Preallocation mode for the new image (default: off)

Members:

location: BlockdevOptionsGluster

Not documented

size: int

Not documented

preallocation: PreallocMode (optional)

Not documented

Since: 2.12

Object: BlockdevCreateOptionsLUKS ¶

Driver specific image creation options for LUKS.

file Node to create the image format on size Size of the virtual disk in bytes

Members:

file: BlockdevRef

Not documented

size: int

Not documented

The members of QCryptoBlockCreateOptionsLUKS

Since: 2.12

Object: BlockdevCreateOptionsNfs ¶

Driver specific image creation options for NFS.

location Where to store the new image file size Size of the virtual disk in bytes

Members:

location: BlockdevOptionsNfs

Not documented

size: int

Not documented

Since: 2.12

Object: BlockdevCreateOptionsParallels ¶

Driver specific image creation options for parallels.

file Node to create the image format on size Size of the virtual disk in bytes cluster-size Cluster size in bytes (default: 1 MB)

Members:

file: BlockdevRef

Not documented

size: int

Not documented

cluster-size: int (optional)

Not documented

Since: 2.12

Object: BlockdevCreateOptionsQcow ¶

Driver specific image creation options for qcow.

file Node to create the image format on size Size of the virtual disk in bytes backing-file File name of the backing file if a backing file should be used encrypt Encryption options if the image should be encrypted

Members:

file: BlockdevRef

Not documented

size: int

Not documented

backing-file: string (optional)

Not documented

encrypt: QCryptoBlockCreateOptions (optional)

Not documented

Since: 2.12

Enum: BlockdevQcow2Version ¶

Values:

v2

The original QCOW2 format as introduced in qemu 0.10 (version 2)

v3

The extended QCOW2 format as introduced in qemu 1.1 (version 3)

Since: 2.12

Object: BlockdevCreateOptionsQcow2 ¶

Driver specific image creation options for qcow2.

file Node to create the image format on size Size of the virtual disk in bytes version Compatibility level (default: v3) backing-file File name of the backing file if a backing file should be used backing-fmt Name of the block driver to use for the backing file encrypt Encryption options if the image should be encrypted cluster-size qcow2 cluster size in bytes (default: 65536) preallocation Preallocation mode for the new image (default: off) lazy-refcounts True if refcounts may be updated lazily (default: off) refcount-bits Width of reference counts in bits (default: 16)

Members:

file: BlockdevRef

Not documented

size: int

Not documented

version: BlockdevQcow2Version (optional)

Not documented

backing-file: string (optional)

Not documented

backing-fmt: BlockdevDriver (optional)

Not documented

encrypt: QCryptoBlockCreateOptions (optional)

Not documented

cluster-size: int (optional)

Not documented

preallocation: PreallocMode (optional)

Not documented

lazy-refcounts: boolean (optional)

Not documented

refcount-bits: int (optional)

Not documented

Since: 2.12

Object: BlockdevCreateOptionsQed ¶

Driver specific image creation options for qed.

file Node to create the image format on size Size of the virtual disk in bytes backing-file File name of the backing file if a backing file should be used backing-fmt Name of the block driver to use for the backing file cluster-size Cluster size in bytes (default: 65536) table-size L1/L2 table size (in clusters)

Members:

file: BlockdevRef

Not documented

size: int

Not documented

backing-file: string (optional)

Not documented

backing-fmt: BlockdevDriver (optional)

Not documented

cluster-size: int (optional)

Not documented

table-size: int (optional)

Not documented

Since: 2.12

Object: BlockdevCreateOptionsRbd ¶

Driver specific image creation options for rbd/Ceph.

location Where to store the new image file. This location cannot point to a snapshot. size Size of the virtual disk in bytes cluster-size RBD object size

Members:

location: BlockdevOptionsRbd

Not documented

size: int

Not documented

cluster-size: int (optional)

Not documented

Since: 2.12

Enum: SheepdogRedundancyType ¶

full Create a fully replicated vdi with x copies erasure-coded Create an erasure coded vdi with x data strips and y parity strips

Values:

full

Not documented

erasure-coded

Not documented

Since: 2.12

Object: SheepdogRedundancyFull ¶

copies Number of copies to use (between 1 and 31)

Members:

copies: int

Not documented

Since: 2.12

Object: SheepdogRedundancyErasureCoded ¶

data-strips Number of data strips to use (one of {2,4,8,16}) parity-strips Number of parity strips to use (between 1 and 15)

Members:

data-strips: int

Not documented

parity-strips: int

Not documented

Since: 2.12

Object: SheepdogRedundancy ¶

Members:

type: SheepdogRedundancyType

Not documented

The members of SheepdogRedundancyFull when type is "full"

The members of SheepdogRedundancyErasureCoded when type is "erasure-coded"

Since: 2.12

Object: BlockdevCreateOptionsSheepdog ¶

Driver specific image creation options for Sheepdog.

location Where to store the new image file size Size of the virtual disk in bytes backing-file File name of a base image preallocation Preallocation mode (allowed values: off, full) redundancy Redundancy of the image object-size Object size of the image

Members:

location: BlockdevOptionsSheepdog

Not documented

size: int

Not documented

backing-file: string (optional)

Not documented

preallocation: PreallocMode (optional)

Not documented

redundancy: SheepdogRedundancy (optional)

Not documented

object-size: int (optional)

Not documented

Since: 2.12

Object: BlockdevCreateOptionsSsh ¶

Driver specific image creation options for SSH.

location Where to store the new image file size Size of the virtual disk in bytes

Members:

location: BlockdevOptionsSsh

Not documented

size: int

Not documented

Since: 2.12

Object: BlockdevCreateOptionsVdi ¶

Driver specific image creation options for VDI.

file Node to create the image format on size Size of the virtual disk in bytes preallocation Preallocation mode for the new image (allowed values: off, metadata; default: off)

Members:

file: BlockdevRef

Not documented

size: int

Not documented

preallocation: PreallocMode (optional)

Not documented

Since: 2.12

Enum: BlockdevVhdxSubformat ¶

Values:

dynamic

Growing image file

fixed

Preallocated fixed-size image file

Since: 2.12

Object: BlockdevCreateOptionsVhdx ¶

Driver specific image creation options for vhdx.

file Node to create the image format on size Size of the virtual disk in bytes log-size Log size in bytes, must be a multiple of 1 MB (default: 1 MB) block-size Block size in bytes, must be a multiple of 1 MB and not larger than 256 MB (default: automatically choose a block size depending on the image size) subformat vhdx subformat (default: dynamic) block-state-zero Force use of payload blocks of type ’ZERO’. Non-standard, but default. Do not set to ’off’ when using ’qemu-img convert’ with subformat=dynamic.

Members:

file: BlockdevRef

Not documented

size: int

Not documented

log-size: int (optional)

Not documented

block-size: int (optional)

Not documented

subformat: BlockdevVhdxSubformat (optional)

Not documented

block-state-zero: boolean (optional)

Not documented

Since: 2.12

Enum: BlockdevVpcSubformat ¶

Values:

dynamic

Growing image file

fixed

Preallocated fixed-size image file

Since: 2.12

Object: BlockdevCreateOptionsVpc ¶

Driver specific image creation options for vpc (VHD).

file Node to create the image format on size Size of the virtual disk in bytes subformat vhdx subformat (default: dynamic) force-size Force use of the exact byte size instead of rounding to the next size that can be represented in CHS geometry (default: false)

Members:

file: BlockdevRef

Not documented

size: int

Not documented

subformat: BlockdevVpcSubformat (optional)

Not documented

force-size: boolean (optional)

Not documented

Since: 2.12

Object: BlockdevCreateNotSupported ¶

This is used for all drivers that don’t support creating images.

Since: 2.12

Object: BlockdevCreateOptions ¶

Options for creating an image format on a given node.

driver block driver to create the image format

Members:

driver: BlockdevDriver

Not documented

The members of BlockdevCreateNotSupported when driver is "blkdebug"

The members of BlockdevCreateNotSupported when driver is "blkverify"

The members of BlockdevCreateNotSupported when driver is "bochs"

The members of BlockdevCreateNotSupported when driver is "cloop"

The members of BlockdevCreateNotSupported when driver is "dmg"

The members of BlockdevCreateOptionsFile when driver is "file"

The members of BlockdevCreateNotSupported when driver is "ftp"

The members of BlockdevCreateNotSupported when driver is "ftps"

The members of BlockdevCreateOptionsGluster when driver is "gluster"

The members of BlockdevCreateNotSupported when driver is "host_cdrom"

The members of BlockdevCreateNotSupported when driver is "host_device"

The members of BlockdevCreateNotSupported when driver is "http"

The members of BlockdevCreateNotSupported when driver is "https"

The members of BlockdevCreateNotSupported when driver is "iscsi"

The members of BlockdevCreateOptionsLUKS when driver is "luks"

The members of BlockdevCreateNotSupported when driver is "nbd"

The members of BlockdevCreateOptionsNfs when driver is "nfs"

The members of BlockdevCreateNotSupported when driver is "null-aio"

The members of BlockdevCreateNotSupported when driver is "null-co"

The members of BlockdevCreateNotSupported when driver is "nvme"

The members of BlockdevCreateOptionsParallels when driver is "parallels"

The members of BlockdevCreateOptionsQcow when driver is "qcow"

The members of BlockdevCreateOptionsQcow2 when driver is "qcow2"

The members of BlockdevCreateOptionsQed when driver is "qed"

The members of BlockdevCreateNotSupported when driver is "quorum"

The members of BlockdevCreateNotSupported when driver is "raw"

The members of BlockdevCreateOptionsRbd when driver is "rbd"

The members of BlockdevCreateNotSupported when driver is "replication"

The members of BlockdevCreateOptionsSheepdog when driver is "sheepdog"

The members of BlockdevCreateOptionsSsh when driver is "ssh"

The members of BlockdevCreateNotSupported when driver is "throttle"

The members of BlockdevCreateOptionsVdi when driver is "vdi"

The members of BlockdevCreateOptionsVhdx when driver is "vhdx"

The members of BlockdevCreateNotSupported when driver is "vmdk"

The members of BlockdevCreateOptionsVpc when driver is "vpc"

The members of BlockdevCreateNotSupported when driver is "vvfat"

The members of BlockdevCreateNotSupported when driver is "vxhs"

Since: 2.12

Command: x-blockdev-create ¶

Create an image format on a given node. TODO Replace with something asynchronous (block job?)

Arguments: the members of BlockdevCreateOptions

Since: 2.12

Command: blockdev-open-tray ¶

Opens a block device’s tray. If there is a block driver state tree inserted as a medium, it will become inaccessible to the guest (but it will remain associated to the block device, so closing the tray will make it accessible again).

If the tray was already open before, this will be a no-op.

Once the tray opens, a DEVICE_TRAY_MOVED event is emitted. There are cases in which no such event will be generated, these include:

• if the guest has locked the tray, force is false and the guest does not respond to the eject request
• if the BlockBackend denoted by device does not have a guest device attached to it
• if the guest device does not have an actual tray

Arguments:

device: string (optional)

Block device name (deprecated, use id instead)

id: string (optional)

The name or QOM path of the guest device (since: 2.8)

force: boolean (optional)

if false (the default), an eject request will be sent to the guest if it has locked the tray (and the tray will not be opened immediately); if true, the tray will be opened regardless of whether it is locked

Since: 2.5

Example:

-> { "execute": "blockdev-open-tray",
     "arguments": { "id": "ide0-1-0" } }

<- { "timestamp": { "seconds": 1418751016,
                    "microseconds": 716996 },
     "event": "DEVICE_TRAY_MOVED",
     "data": { "device": "ide1-cd0",
               "id": "ide0-1-0",
               "tray-open": true } }

<- { "return": {} }

Command: blockdev-close-tray ¶

Closes a block device’s tray. If there is a block driver state tree associated with the block device (which is currently ejected), that tree will be loaded as the medium.

If the tray was already closed before, this will be a no-op.

Arguments:

device: string (optional)

Block device name (deprecated, use id instead)

id: string (optional)

The name or QOM path of the guest device (since: 2.8)

Since: 2.5

Example:

-> { "execute": "blockdev-close-tray",
     "arguments": { "id": "ide0-1-0" } }

<- { "timestamp": { "seconds": 1418751345,
                    "microseconds": 272147 },
     "event": "DEVICE_TRAY_MOVED",
     "data": { "device": "ide1-cd0",
               "id": "ide0-1-0",
               "tray-open": false } }

<- { "return": {} }

Command: blockdev-remove-medium ¶

Removes a medium (a block driver state tree) from a block device. That block device’s tray must currently be open (unless there is no attached guest device).

If the tray is open and there is no medium inserted, this will be a no-op.

Arguments:

id: string

The name or QOM path of the guest device

Since: 2.12

Example:

-> { "execute": "blockdev-remove-medium",
     "arguments": { "id": "ide0-1-0" } }

<- { "error": { "class": "GenericError",
                "desc": "Tray of device 'ide0-1-0' is not open" } }

-> { "execute": "blockdev-open-tray",
     "arguments": { "id": "ide0-1-0" } }

<- { "timestamp": { "seconds": 1418751627,
                    "microseconds": 549958 },
     "event": "DEVICE_TRAY_MOVED",
     "data": { "device": "ide1-cd0",
               "id": "ide0-1-0",
               "tray-open": true } }

<- { "return": {} }

-> { "execute": "blockdev-remove-medium",
     "arguments": { "id": "ide0-1-0" } }

<- { "return": {} }

Command: blockdev-insert-medium ¶

Inserts a medium (a block driver state tree) into a block device. That block device’s tray must currently be open (unless there is no attached guest device) and there must be no medium inserted already.

Arguments:

id: string

The name or QOM path of the guest device

node-name: string

name of a node in the block driver state graph

Since: 2.12

Example:

-> { "execute": "blockdev-add",
     "arguments": {
         "node-name": "node0",
         "driver": "raw",
         "file": { "driver": "file",
                   "filename": "fedora.iso" } } }
<- { "return": {} }

-> { "execute": "blockdev-insert-medium",
     "arguments": { "id": "ide0-1-0",
                    "node-name": "node0" } }

<- { "return": {} }

Enum: BlockdevChangeReadOnlyMode ¶

Specifies the new read-only mode of a block device subject to the blockdev-change-medium command.

Values:

retain

Retains the current read-only mode

read-only

Makes the device read-only

read-write

Makes the device writable

Since: 2.3

Command: blockdev-change-medium ¶

Changes the medium inserted into a block device by ejecting the current medium and loading a new image file which is inserted as the new medium (this command combines blockdev-open-tray, blockdev-remove-medium, blockdev-insert-medium and blockdev-close-tray).

Arguments:

device: string (optional)

Block device name (deprecated, use id instead)

id: string (optional)

The name or QOM path of the guest device (since: 2.8)

filename: string

filename of the new image to be loaded

format: string (optional)

format to open the new image with (defaults to the probed format)

read-only-mode: BlockdevChangeReadOnlyMode (optional)

change the read-only mode of the device; defaults to ’retain’

Since: 2.5

Examples:

1. Change a removable medium

-> { "execute": "blockdev-change-medium",
     "arguments": { "id": "ide0-1-0",
                    "filename": "/srv/images/Fedora-12-x86_64-DVD.iso",
                    "format": "raw" } }
<- { "return": {} }

2. Load a read-only medium into a writable drive

-> { "execute": "blockdev-change-medium",
     "arguments": { "id": "floppyA",
                    "filename": "/srv/images/ro.img",
                    "format": "raw",
                    "read-only-mode": "retain" } }

<- { "error":
     { "class": "GenericError",
       "desc": "Could not open '/srv/images/ro.img': Permission denied" } }

-> { "execute": "blockdev-change-medium",
     "arguments": { "id": "floppyA",
                    "filename": "/srv/images/ro.img",
                    "format": "raw",
                    "read-only-mode": "read-only" } }

<- { "return": {} }

Enum: BlockErrorAction ¶

An enumeration of action that has been taken when a DISK I/O occurs

Values:

ignore

error has been ignored

report

error has been reported to the device

stop

error caused VM to be stopped

Since: 2.1

Event: BLOCK_IMAGE_CORRUPTED ¶

Emitted when a disk image is being marked corrupt. The image can be identified by its device or node name. The ’device’ field is always present for compatibility reasons, but it can be empty ("") if the image does not have a device name associated.

Arguments:

device: string

device name. This is always present for compatibility reasons, but it can be empty ("") if the image does not have a device name associated.

node-name: string (optional)

node name (Since: 2.4)

msg: string

informative message for human consumption, such as the kind of corruption being detected. It should not be parsed by machine as it is not guaranteed to be stable

offset: int (optional)

if the corruption resulted from an image access, this is the host’s access offset into the image

size: int (optional)

if the corruption resulted from an image access, this is the access size

fatal: boolean

if set, the image is marked corrupt and therefore unusable after this event and must be repaired (Since 2.2; before, every BLOCK_IMAGE_CORRUPTED event was fatal)

Note: If action is "stop", a STOP event will eventually follow the BLOCK_IO_ERROR event.

Example:

<- { "event": "BLOCK_IMAGE_CORRUPTED",
     "data": { "device": "ide0-hd0", "node-name": "node0",
               "msg": "Prevented active L1 table overwrite", "offset": 196608,
               "size": 65536 },
     "timestamp": { "seconds": 1378126126, "microseconds": 966463 } }

Since: 1.7

Event: BLOCK_IO_ERROR ¶

Emitted when a disk I/O error occurs

Arguments:

device: string

device name. This is always present for compatibility reasons, but it can be empty ("") if the image does not have a device name associated.

node-name: string (optional)

node name. Note that errors may be reported for the root node that is directly attached to a guest device rather than for the node where the error occurred. The node name is not present if the drive is empty. (Since: 2.8)

operation: IoOperationType

I/O operation

action: BlockErrorAction

action that has been taken

nospace: boolean (optional)

true if I/O error was caused due to a no-space condition. This key is only present if query-block’s io-status is present, please see query-block documentation for more information (since: 2.2)

reason: string

human readable string describing the error cause. (This field is a debugging aid for humans, it should not be parsed by applications) (since: 2.2)

Note: If action is "stop", a STOP event will eventually follow the BLOCK_IO_ERROR event

Since: 0.13.0

Example:

<- { "event": "BLOCK_IO_ERROR",
     "data": { "device": "ide0-hd1",
               "node-name": "#block212",
               "operation": "write",
               "action": "stop" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

Event: BLOCK_JOB_COMPLETED ¶

Emitted when a block job has completed

Arguments:

type: BlockJobType

job type

device: string

The job identifier. Originally the device name but other values are allowed since QEMU 2.7

len: int

maximum progress value

offset: int

current progress value. On success this is equal to len. On failure this is less than len

speed: int

rate limit, bytes per second

error: string (optional)

error message. Only present on failure. This field contains a human-readable error message. There are no semantics other than that streaming has failed and clients should not try to interpret the error string

Since: 1.1

Example:

<- { "event": "BLOCK_JOB_COMPLETED",
     "data": { "type": "stream", "device": "virtio-disk0",
               "len": 10737418240, "offset": 10737418240,
               "speed": 0 },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }

Event: BLOCK_JOB_CANCELLED ¶

Emitted when a block job has been cancelled

Arguments:

type: BlockJobType

job type

device: string

The job identifier. Originally the device name but other values are allowed since QEMU 2.7

len: int

maximum progress value

offset: int

current progress value. On success this is equal to len. On failure this is less than len

speed: int

rate limit, bytes per second

Since: 1.1

Example:

<- { "event": "BLOCK_JOB_CANCELLED",
     "data": { "type": "stream", "device": "virtio-disk0",
               "len": 10737418240, "offset": 134217728,
               "speed": 0 },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }

Event: BLOCK_JOB_ERROR ¶

Emitted when a block job encounters an error

Arguments:

device: string

The job identifier. Originally the device name but other values are allowed since QEMU 2.7

operation: IoOperationType

I/O operation

action: BlockErrorAction

action that has been taken

Since: 1.3

Example:

<- { "event": "BLOCK_JOB_ERROR",
     "data": { "device": "ide0-hd1",
               "operation": "write",
               "action": "stop" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

Event: BLOCK_JOB_READY ¶

Emitted when a block job is ready to complete

Arguments:

type: BlockJobType

job type

device: string

The job identifier. Originally the device name but other values are allowed since QEMU 2.7

len: int

maximum progress value

offset: int

current progress value. On success this is equal to len. On failure this is less than len

speed: int

rate limit, bytes per second

Note: The "ready to complete" status is always reset by a BLOCK_JOB_ERROR event

Since: 1.3

Example:

<- { "event": "BLOCK_JOB_READY",
     "data": { "device": "drive0", "type": "mirror", "speed": 0,
               "len": 2097152, "offset": 2097152 }
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

Event: BLOCK_JOB_PENDING ¶

Emitted when a block job is awaiting explicit authorization to finalize graph changes via block-job-finalize. If this job is part of a transaction, it will not emit this event until the transaction has converged first.

Arguments:

type: BlockJobType

job type

id: string

The job identifier.

Since: 2.12

Example:

<- { "event": "BLOCK_JOB_WAITING",
     "data": { "device": "drive0", "type": "mirror" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

Enum: PreallocMode ¶

Preallocation mode of QEMU image file

Values:

off

no preallocation

metadata

preallocate only for metadata

falloc

like full preallocation but allocate disk space by posix_fallocate() rather than writing zeros.

full

preallocate all data by writing zeros to device to ensure disk space is really available. full preallocation also sets up metadata correctly.

Since: 2.2

Event: BLOCK_WRITE_THRESHOLD ¶

Emitted when writes on block device reaches or exceeds the configured write threshold. For thin-provisioned devices, this means the device should be extended to avoid pausing for disk exhaustion. The event is one shot. Once triggered, it needs to be re-registered with another block-set-write-threshold command.

Arguments:

node-name: string

graph node name on which the threshold was exceeded.

amount-exceeded: int

amount of data which exceeded the threshold, in bytes.

write-threshold: int

last configured threshold, in bytes.

Since: 2.3

Command: block-set-write-threshold ¶

Change the write threshold for a block drive. An event will be delivered if a write to this block drive crosses the configured threshold. The threshold is an offset, thus must be non-negative. Default is no write threshold. Setting the threshold to zero disables it.

This is useful to transparently resize thin-provisioned drives without the guest OS noticing.

Arguments:

node-name: string

graph node name on which the threshold must be set.

write-threshold: int

configured threshold for the block device, bytes. Use 0 to disable the threshold.

Since: 2.3

Example:

-> { "execute": "block-set-write-threshold",
     "arguments": { "node-name": "mydev",
                    "write-threshold": 17179869184 } }
<- { "return": {} }

Command: x-blockdev-change ¶

Dynamically reconfigure the block driver state graph. It can be used to add, remove, insert or replace a graph node. Currently only the Quorum driver implements this feature to add or remove its child. This is useful to fix a broken quorum child.

If node is specified, it will be inserted under parent. child may not be specified in this case. If both parent and child are specified but node is not, child will be detached from parent.

Arguments:

parent: string

the id or name of the parent node.

child: string (optional)

the name of a child under the given parent node.

node: string (optional)

the name of the node that will be added.

Note: this command is experimental, and its API is not stable. It does not support all kinds of operations, all kinds of children, nor all block drivers.

FIXME Removing children from a quorum node means introducing gaps in the child indices. This cannot be represented in the ’children’ list of BlockdevOptionsQuorum, as returned by .bdrv_refresh_filename().

Warning: The data in a new quorum child MUST be consistent with that of the rest of the array.

Since: 2.7

Example:

1. Add a new node to a quorum
-> { "execute": "blockdev-add",
     "arguments": {
         "driver": "raw",
         "node-name": "new_node",
         "file": { "driver": "file",
                   "filename": "test.raw" } } }
<- { "return": {} }
-> { "execute": "x-blockdev-change",
     "arguments": { "parent": "disk1",
                    "node": "new_node" } }
<- { "return": {} }

2. Delete a quorum's node
-> { "execute": "x-blockdev-change",
     "arguments": { "parent": "disk1",
                    "child": "children.1" } }
<- { "return": {} }

Command: x-blockdev-set-iothread ¶

Move node and its children into the iothread. If iothread is null then move node and its children into the main loop.

The node must not be attached to a BlockBackend.

Arguments:

node-name: string

the name of the block driver node

iothread: StrOrNull

the name of the IOThread object or null for the main loop

force: boolean (optional)

true if the node and its children should be moved when a BlockBackend is already attached

Note: this command is experimental and intended for test cases that need control over IOThreads only.

Since: 2.12

Example:

1. Move a node into an IOThread
-> { "execute": "x-blockdev-set-iothread",
     "arguments": { "node-name": "disk1",
                    "iothread": "iothread0" } }
<- { "return": {} }

2. Move a node into the main loop
-> { "execute": "x-blockdev-set-iothread",
     "arguments": { "node-name": "disk1",
                    "iothread": null } }
<- { "return": {} }

1.7.2 Additional block stuff (VM related)

Enum: BiosAtaTranslation ¶

Policy that BIOS should use to interpret cylinder/head/sector addresses. Note that Bochs BIOS and SeaBIOS will not actually translate logical CHS to physical; instead, they will use logical block addressing.

Values:

auto

If cylinder/heads/sizes are passed, choose between none and LBA depending on the size of the disk. If they are not passed, choose none if QEMU can guess that the disk had 16 or fewer heads, large if QEMU can guess that the disk had 131072 or fewer tracks across all heads (i.e. cylinders*heads<131072), otherwise LBA.

none

The physical disk geometry is equal to the logical geometry.

lba

Assume 63 sectors per track and one of 16, 32, 64, 128 or 255 heads (if fewer than 255 are enough to cover the whole disk with 1024 cylinders/head). The number of cylinders/head is then computed based on the number of sectors and heads.

large

The number of cylinders per head is scaled down to 1024 by correspondingly scaling up the number of heads.

rechs

Same as large, but first convert a 16-head geometry to 15-head, by proportionally scaling up the number of cylinders/head.

Since: 2.0

Enum: FloppyDriveType ¶

Type of Floppy drive to be emulated by the Floppy Disk Controller.

Values:

144

1.44MB 3.5" drive

288

2.88MB 3.5" drive

120

1.2MB 5.25" drive

none

No drive connected

auto

Automatically determined by inserted media at boot

Since: 2.6

Object: BlockdevSnapshotInternal ¶

Members:

device: string

the device name or node-name of a root node to generate the snapshot from

name: string

the name of the internal snapshot to be created

Notes: In transaction, if name is empty, or any snapshot matching name exists, the operation will fail. Only some image formats support it, for example, qcow2, rbd, and sheepdog.

Since: 1.7

Command: blockdev-snapshot-internal-sync ¶

Synchronously take an internal snapshot of a block device, when the format of the image used supports it. If the name is an empty string, or a snapshot with name already exists, the operation will fail.

For the arguments, see the documentation of BlockdevSnapshotInternal.

Returns: nothing on success

If device is not a valid block device, GenericError

If any snapshot matching name exists, or name is empty, GenericError

If the format of the image used does not support it, BlockFormatFeatureNotSupported

Since: 1.7

Example:

-> { "execute": "blockdev-snapshot-internal-sync",
     "arguments": { "device": "ide-hd0",
                    "name": "snapshot0" }
   }
<- { "return": {} }

Command: blockdev-snapshot-delete-internal-sync ¶

Synchronously delete an internal snapshot of a block device, when the format of the image used support it. The snapshot is identified by name or id or both. One of the name or id is required. Return SnapshotInfo for the successfully deleted snapshot.

Arguments:

device: string

the device name or node-name of a root node to delete the snapshot from

id: string (optional)

optional the snapshot’s ID to be deleted

name: string (optional)

optional the snapshot’s name to be deleted

Returns: SnapshotInfo on success If device is not a valid block device, GenericError If snapshot not found, GenericError If the format of the image used does not support it, BlockFormatFeatureNotSupported If id and name are both not specified, GenericError

Since: 1.7

Example:

-> { "execute": "blockdev-snapshot-delete-internal-sync",
     "arguments": { "device": "ide-hd0",
                    "name": "snapshot0" }
   }
<- { "return": {
                   "id": "1",
                   "name": "snapshot0",
                   "vm-state-size": 0,
                   "date-sec": 1000012,
                   "date-nsec": 10,
                   "vm-clock-sec": 100,
                   "vm-clock-nsec": 20
     }
   }

Command: eject ¶

Ejects a device from a removable drive.

Arguments:

device: string (optional)

Block device name (deprecated, use id instead)

id: string (optional)

The name or QOM path of the guest device (since: 2.8)

force: boolean (optional)

If true, eject regardless of whether the drive is locked. If not specified, the default value is false.

Returns: Nothing on success

If device is not a valid block device, DeviceNotFound

Notes: Ejecting a device with no media results in success

Since: 0.14.0

Example:

-> { "execute": "eject", "arguments": { "id": "ide1-0-1" } }
<- { "return": {} }

Command: nbd-server-start ¶

Start an NBD server listening on the given host and port. Block devices can then be exported using nbd-server-add. The NBD server will present them as named exports; for example, another QEMU instance could refer to them as "nbd:HOST:PORT:exportname=NAME".

Arguments:

addr: SocketAddressLegacy

Address on which to listen.

tls-creds: string (optional)

(optional) ID of the TLS credentials object. Since 2.6

Returns: error if the server is already running.

Since: 1.3.0

Command: nbd-server-add ¶

Export a block node to QEMU’s embedded NBD server.

Arguments:

device: string

The device name or node name of the node to be exported

name: string (optional)

Export name. If unspecified, the device parameter is used as the export name. (Since 2.12)

writable: boolean (optional)

Whether clients should be able to write to the device via the NBD connection (default false).

Returns: error if the server is not running, or export with the same name already exists.

Since: 1.3.0

Enum: NbdServerRemoveMode ¶

Mode for removing an NBD export.

Values:

safe

Remove export if there are no existing connections, fail otherwise.

hard

Drop all connections immediately and remove export.

Potential additional modes to be added in the future:

hide: Just hide export from new clients, leave existing connections as is. Remove export after all clients are disconnected.

soft: Hide export from new clients, answer with ESHUTDOWN for all further requests from existing clients.

Since: 2.12

Command: nbd-server-remove ¶

Remove NBD export by name.

Arguments:

name: string

Export name.

mode: NbdServerRemoveMode (optional)

Mode of command operation. See NbdServerRemoveMode description. Default is ’safe’.

Returns: error if

• the server is not running
• export is not found
• mode is ’safe’ and there are existing connections

Since: 2.12

Command: nbd-server-stop ¶

Stop QEMU’s embedded NBD server, and unregister all devices previously added via nbd-server-add.

Since: 1.3.0

Event: DEVICE_TRAY_MOVED ¶

Emitted whenever the tray of a removable device is moved by the guest or by HMP/QMP commands

Arguments:

device: string

Block device name. This is always present for compatibility reasons, but it can be empty ("") if the image does not have a device name associated.

id: string

The name or QOM path of the guest device (since 2.8)

tray-open: boolean

true if the tray has been opened or false if it has been closed

Since: 1.1

Example:

<- { "event": "DEVICE_TRAY_MOVED",
     "data": { "device": "ide1-cd0",
               "id": "/machine/unattached/device[22]",
               "tray-open": true
     },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

Enum: QuorumOpType ¶

An enumeration of the quorum operation types

Values:

read

read operation

write

write operation

flush

flush operation

Since: 2.6

Event: QUORUM_FAILURE ¶

Emitted by the Quorum block driver if it fails to establish a quorum

Arguments:

reference: string

device name if defined else node name

sector-num: int

number of the first sector of the failed read operation

sectors-count: int

failed read operation sector count

Note: This event is rate-limited.

Since: 2.0

Example:

<- { "event": "QUORUM_FAILURE",
     "data": { "reference": "usr1", "sector-num": 345435, "sectors-count": 5 },
     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }

Event: QUORUM_REPORT_BAD ¶

Emitted to report a corruption of a Quorum file

Arguments:

type: QuorumOpType

quorum operation type (Since 2.6)

error: string (optional)

error message. Only present on failure. This field contains a human-readable error message. There are no semantics other than that the block layer reported an error and clients should not try to interpret the error string.

node-name: string

the graph node name of the block driver state

sector-num: int

number of the first sector of the failed read operation

sectors-count: int

failed read operation sector count

Note: This event is rate-limited.

Since: 2.0

Example:

1. Read operation

{ "event": "QUORUM_REPORT_BAD",
     "data": { "node-name": "node0", "sector-num": 345435, "sectors-count": 5,
               "type": "read" },
     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }

2. Flush operation

{ "event": "QUORUM_REPORT_BAD",
     "data": { "node-name": "node0", "sector-num": 0, "sectors-count": 2097120,
               "type": "flush", "error": "Broken pipe" },
     "timestamp": { "seconds": 1456406829, "microseconds": 291763 } }