migration: introduce postcopy-blocktime capability

[qemu.git] / qapi / migration.json

# -*- Mode: Python -*-
#

##
# = Migration
##

{ 'include': 'common.json' }

##
# @MigrationStats:
#
# Detailed migration status.
#
# @transferred: amount of bytes already transferred to the target VM
#
# @remaining: amount of bytes remaining to be transferred to the target VM
#
# @total: total amount of bytes involved in the migration process
#
# @duplicate: number of duplicate (zero) pages (since 1.2)
#
# @skipped: number of skipped zero pages (since 1.5)
#
# @normal: number of normal pages (since 1.2)
#
# @normal-bytes: number of normal bytes sent (since 1.2)
#
# @dirty-pages-rate: number of pages dirtied by second by the
#        guest (since 1.3)
#
# @mbps: throughput in megabits/sec. (since 1.6)
#
# @dirty-sync-count: number of times that dirty ram was synchronized (since 2.1)
#
# @postcopy-requests: The number of page requests received from the destination
#        (since 2.7)
#
# @page-size: The number of bytes per page for the various page-based
#        statistics (since 2.10)
#
# Since: 0.14.0
##
{ 'struct': 'MigrationStats',
  'data': {'transferred': 'int', 'remaining': 'int', 'total': 'int' ,
           'duplicate': 'int', 'skipped': 'int', 'normal': 'int',
           'normal-bytes': 'int', 'dirty-pages-rate' : 'int',
           'mbps' : 'number', 'dirty-sync-count' : 'int',
           'postcopy-requests' : 'int', 'page-size' : 'int' } }

##
# @XBZRLECacheStats:
#
# Detailed XBZRLE migration cache statistics
#
# @cache-size: XBZRLE cache size
#
# @bytes: amount of bytes already transferred to the target VM
#
# @pages: amount of pages transferred to the target VM
#
# @cache-miss: number of cache miss
#
# @cache-miss-rate: rate of cache miss (since 2.1)
#
# @overflow: number of overflows
#
# Since: 1.2
##
{ 'struct': 'XBZRLECacheStats',
  'data': {'cache-size': 'int', 'bytes': 'int', 'pages': 'int',
           'cache-miss': 'int', 'cache-miss-rate': 'number',
           'overflow': 'int' } }

##
# @MigrationStatus:
#
# An enumeration of migration status.
#
# @none: no migration has ever happened.
#
# @setup: migration process has been initiated.
#
# @cancelling: in the process of cancelling migration.
#
# @cancelled: cancelling migration is finished.
#
# @active: in the process of doing migration.
#
# @postcopy-active: like active, but now in postcopy mode. (since 2.5)
#
# @completed: migration is finished.
#
# @failed: some error occurred during migration process.
#
# @colo: VM is in the process of fault tolerance, VM can not get into this
#        state unless colo capability is enabled for migration. (since 2.8)
#
# @pre-switchover: Paused before device serialisation. (since 2.11)
#
# @device: During device serialisation when pause-before-switchover is enabled
#        (since 2.11)
#
# Since: 2.3
#
##
{ 'enum': 'MigrationStatus',
  'data': [ 'none', 'setup', 'cancelling', 'cancelled',
            'active', 'postcopy-active', 'completed', 'failed', 'colo',
            'pre-switchover', 'device' ] }

##
# @MigrationInfo:
#
# Information about current migration process.
#
# @status: @MigrationStatus describing the current migration status.
#          If this field is not returned, no migration process
#          has been initiated
#
# @ram: @MigrationStats containing detailed migration
#       status, only returned if status is 'active' or
#       'completed'(since 1.2)
#
# @disk: @MigrationStats containing detailed disk migration
#        status, only returned if status is 'active' and it is a block
#        migration
#
# @xbzrle-cache: @XBZRLECacheStats containing detailed XBZRLE
#                migration statistics, only returned if XBZRLE feature is on and
#                status is 'active' or 'completed' (since 1.2)
#
# @total-time: total amount of milliseconds since migration started.
#        If migration has ended, it returns the total migration
#        time. (since 1.2)
#
# @downtime: only present when migration finishes correctly
#        total downtime in milliseconds for the guest.
#        (since 1.3)
#
# @expected-downtime: only present while migration is active
#        expected downtime in milliseconds for the guest in last walk
#        of the dirty bitmap. (since 1.3)
#
# @setup-time: amount of setup time in milliseconds _before_ the
#        iterations begin but _after_ the QMP command is issued. This is designed
#        to provide an accounting of any activities (such as RDMA pinning) which
#        may be expensive, but do not actually occur during the iterative
#        migration rounds themselves. (since 1.6)
#
# @cpu-throttle-percentage: percentage of time guest cpus are being
#        throttled during auto-converge. This is only present when auto-converge
#        has started throttling guest cpus. (Since 2.7)
#
# @error-desc: the human readable error description string, when
#              @status is 'failed'. Clients should not attempt to parse the
#              error strings. (Since 2.7)
#
# Since: 0.14.0
##
{ 'struct': 'MigrationInfo',
  'data': {'*status': 'MigrationStatus', '*ram': 'MigrationStats',
           '*disk': 'MigrationStats',
           '*xbzrle-cache': 'XBZRLECacheStats',
           '*total-time': 'int',
           '*expected-downtime': 'int',
           '*downtime': 'int',
           '*setup-time': 'int',
           '*cpu-throttle-percentage': 'int',
           '*error-desc': 'str'} }

##
# @query-migrate:
#
# Returns information about current migration process. If migration
# is active there will be another json-object with RAM migration
# status and if block migration is active another one with block
# migration status.
#
# Returns: @MigrationInfo
#
# Since: 0.14.0
#
# Example:
#
# 1. Before the first migration
#
# -> { "execute": "query-migrate" }
# <- { "return": {} }
#
# 2. Migration is done and has succeeded
#
# -> { "execute": "query-migrate" }
# <- { "return": {
#         "status": "completed",
#         "ram":{
#           "transferred":123,
#           "remaining":123,
#           "total":246,
#           "total-time":12345,
#           "setup-time":12345,
#           "downtime":12345,
#           "duplicate":123,
#           "normal":123,
#           "normal-bytes":123456,
#           "dirty-sync-count":15
#         }
#      }
#    }
#
# 3. Migration is done and has failed
#
# -> { "execute": "query-migrate" }
# <- { "return": { "status": "failed" } }
#
# 4. Migration is being performed and is not a block migration:
#
# -> { "execute": "query-migrate" }
# <- {
#       "return":{
#          "status":"active",
#          "ram":{
#             "transferred":123,
#             "remaining":123,
#             "total":246,
#             "total-time":12345,
#             "setup-time":12345,
#             "expected-downtime":12345,
#             "duplicate":123,
#             "normal":123,
#             "normal-bytes":123456,
#             "dirty-sync-count":15
#          }
#       }
#    }
#
# 5. Migration is being performed and is a block migration:
#
# -> { "execute": "query-migrate" }
# <- {
#       "return":{
#          "status":"active",
#          "ram":{
#             "total":1057024,
#             "remaining":1053304,
#             "transferred":3720,
#             "total-time":12345,
#             "setup-time":12345,
#             "expected-downtime":12345,
#             "duplicate":123,
#             "normal":123,
#             "normal-bytes":123456,
#             "dirty-sync-count":15
#          },
#          "disk":{
#             "total":20971520,
#             "remaining":20880384,
#             "transferred":91136
#          }
#       }
#    }
#
# 6. Migration is being performed and XBZRLE is active:
#
# -> { "execute": "query-migrate" }
# <- {
#       "return":{
#          "status":"active",
#          "capabilities" : [ { "capability": "xbzrle", "state" : true } ],
#          "ram":{
#             "total":1057024,
#             "remaining":1053304,
#             "transferred":3720,
#             "total-time":12345,
#             "setup-time":12345,
#             "expected-downtime":12345,
#             "duplicate":10,
#             "normal":3333,
#             "normal-bytes":3412992,
#             "dirty-sync-count":15
#          },
#          "xbzrle-cache":{
#             "cache-size":67108864,
#             "bytes":20971520,
#             "pages":2444343,
#             "cache-miss":2244,
#             "cache-miss-rate":0.123,
#             "overflow":34434
#          }
#       }
#    }
#
##
{ 'command': 'query-migrate', 'returns': 'MigrationInfo' }

##
# @MigrationCapability:
#
# Migration capabilities enumeration
#
# @xbzrle: Migration supports xbzrle (Xor Based Zero Run Length Encoding).
#          This feature allows us to minimize migration traffic for certain work
#          loads, by sending compressed difference of the pages
#
# @rdma-pin-all: Controls whether or not the entire VM memory footprint is
#          mlock()'d on demand or all at once. Refer to docs/rdma.txt for usage.
#          Disabled by default. (since 2.0)
#
# @zero-blocks: During storage migration encode blocks of zeroes efficiently. This
#          essentially saves 1MB of zeroes per block on the wire. Enabling requires
#          source and target VM to support this feature. To enable it is sufficient
#          to enable the capability on the source VM. The feature is disabled by
#          default. (since 1.6)
#
# @compress: Use multiple compression threads to accelerate live migration.
#          This feature can help to reduce the migration traffic, by sending
#          compressed pages. Please note that if compress and xbzrle are both
#          on, compress only takes effect in the ram bulk stage, after that,
#          it will be disabled and only xbzrle takes effect, this can help to
#          minimize migration traffic. The feature is disabled by default.
#          (since 2.4 )
#
# @events: generate events for each migration state change
#          (since 2.4 )
#
# @auto-converge: If enabled, QEMU will automatically throttle down the guest
#          to speed up convergence of RAM migration. (since 1.6)
#
# @postcopy-ram: Start executing on the migration target before all of RAM has
#          been migrated, pulling the remaining pages along as needed. The
#          capacity must have the same setting on both source and target
#          or migration will not even start. NOTE: If the migration fails during
#          postcopy the VM will fail.  (since 2.6)
#
# @x-colo: If enabled, migration will never end, and the state of the VM on the
#        primary side will be migrated continuously to the VM on secondary
#        side, this process is called COarse-Grain LOck Stepping (COLO) for
#        Non-stop Service. (since 2.8)
#
# @release-ram: if enabled, qemu will free the migrated ram pages on the source
#        during postcopy-ram migration. (since 2.9)
#
# @block: If enabled, QEMU will also migrate the contents of all block
#          devices.  Default is disabled.  A possible alternative uses
#          mirror jobs to a builtin NBD server on the destination, which
#          offers more flexibility.
#          (Since 2.10)
#
# @return-path: If enabled, migration will use the return path even
#               for precopy. (since 2.10)
#
# @pause-before-switchover: Pause outgoing migration before serialising device
#          state and before disabling block IO (since 2.11)
#
# @x-multifd: Use more than one fd for migration (since 2.11)
#
#
# @dirty-bitmaps: If enabled, QEMU will migrate named dirty bitmaps.
#                 (since 2.12)
#
# @postcopy-blocktime: Calculate downtime for postcopy live migration
#                     (since 2.13)
#
# Since: 1.2
##
{ 'enum': 'MigrationCapability',
  'data': ['xbzrle', 'rdma-pin-all', 'auto-converge', 'zero-blocks',
           'compress', 'events', 'postcopy-ram', 'x-colo', 'release-ram',
           'block', 'return-path', 'pause-before-switchover', 'x-multifd',
           'dirty-bitmaps', 'postcopy-blocktime' ] }

##
# @MigrationCapabilityStatus:
#
# Migration capability information
#
# @capability: capability enum
#
# @state: capability state bool
#
# Since: 1.2
##
{ 'struct': 'MigrationCapabilityStatus',
  'data': { 'capability' : 'MigrationCapability', 'state' : 'bool' } }

##
# @migrate-set-capabilities:
#
# Enable/Disable the following migration capabilities (like xbzrle)
#
# @capabilities: json array of capability modifications to make
#
# Since: 1.2
#
# Example:
#
# -> { "execute": "migrate-set-capabilities" , "arguments":
#      { "capabilities": [ { "capability": "xbzrle", "state": true } ] } }
#
##
{ 'command': 'migrate-set-capabilities',
  'data': { 'capabilities': ['MigrationCapabilityStatus'] } }

##
# @query-migrate-capabilities:
#
# Returns information about the current migration capabilities status
#
# Returns: @MigrationCapabilitiesStatus
#
# Since: 1.2
#
# Example:
#
# -> { "execute": "query-migrate-capabilities" }
# <- { "return": [
#       {"state": false, "capability": "xbzrle"},
#       {"state": false, "capability": "rdma-pin-all"},
#       {"state": false, "capability": "auto-converge"},
#       {"state": false, "capability": "zero-blocks"},
#       {"state": false, "capability": "compress"},
#       {"state": true, "capability": "events"},
#       {"state": false, "capability": "postcopy-ram"},
#       {"state": false, "capability": "x-colo"}
#    ]}
#
##
{ 'command': 'query-migrate-capabilities', 'returns':   ['MigrationCapabilityStatus']}

##
# @MigrationParameter:
#
# Migration parameters enumeration
#
# @compress-level: Set the compression level to be used in live migration,
#          the compression level is an integer between 0 and 9, where 0 means
#          no compression, 1 means the best compression speed, and 9 means best
#          compression ratio which will consume more CPU.
#
# @compress-threads: Set compression thread count to be used in live migration,
#          the compression thread count is an integer between 1 and 255.
#
# @decompress-threads: Set decompression thread count to be used in live
#          migration, the decompression thread count is an integer between 1
#          and 255. Usually, decompression is at least 4 times as fast as
#          compression, so set the decompress-threads to the number about 1/4
#          of compress-threads is adequate.
#
# @cpu-throttle-initial: Initial percentage of time guest cpus are throttled
#                        when migration auto-converge is activated. The
#                        default value is 20. (Since 2.7)
#
# @cpu-throttle-increment: throttle percentage increase each time
#                          auto-converge detects that migration is not making
#                          progress. The default value is 10. (Since 2.7)
#
# @tls-creds: ID of the 'tls-creds' object that provides credentials for
#             establishing a TLS connection over the migration data channel.
#             On the outgoing side of the migration, the credentials must
#             be for a 'client' endpoint, while for the incoming side the
#             credentials must be for a 'server' endpoint. Setting this
#             will enable TLS for all migrations. The default is unset,
#             resulting in unsecured migration at the QEMU level. (Since 2.7)
#
# @tls-hostname: hostname of the target host for the migration. This is
#                required when using x509 based TLS credentials and the
#                migration URI does not already include a hostname. For
#                example if using fd: or exec: based migration, the
#                hostname must be provided so that the server's x509
#                certificate identity can be validated. (Since 2.7)
#
# @max-bandwidth: to set maximum speed for migration. maximum speed in
#                 bytes per second. (Since 2.8)
#
# @downtime-limit: set maximum tolerated downtime for migration. maximum
#                  downtime in milliseconds (Since 2.8)
#
# @x-checkpoint-delay: The delay time (in ms) between two COLO checkpoints in
#          periodic mode. (Since 2.8)
#
# @block-incremental: Affects how much storage is migrated when the
#       block migration capability is enabled.  When false, the entire
#       storage backing chain is migrated into a flattened image at
#       the destination; when true, only the active qcow2 layer is
#       migrated and the destination must already have access to the
#       same backing chain as was used on the source.  (since 2.10)
#
# @x-multifd-channels: Number of channels used to migrate data in
#                     parallel. This is the same number that the
#                     number of sockets used for migration.  The
#                     default value is 2 (since 2.11)
#
# @x-multifd-page-count: Number of pages sent together to a thread.
#                        The default value is 16 (since 2.11)
#
# @xbzrle-cache-size: cache size to be used by XBZRLE migration.  It
#                     needs to be a multiple of the target page size
#                     and a power of 2
#                     (Since 2.11)
#
# Since: 2.4
##
{ 'enum': 'MigrationParameter',
  'data': ['compress-level', 'compress-threads', 'decompress-threads',
           'cpu-throttle-initial', 'cpu-throttle-increment',
           'tls-creds', 'tls-hostname', 'max-bandwidth',
           'downtime-limit', 'x-checkpoint-delay', 'block-incremental',
           'x-multifd-channels', 'x-multifd-page-count',
           'xbzrle-cache-size' ] }

##
# @MigrateSetParameters:
#
# @compress-level: compression level
#
# @compress-threads: compression thread count
#
# @decompress-threads: decompression thread count
#
# @cpu-throttle-initial: Initial percentage of time guest cpus are
#                        throttled when migration auto-converge is activated.
#                        The default value is 20. (Since 2.7)
#
# @cpu-throttle-increment: throttle percentage increase each time
#                          auto-converge detects that migration is not making
#                          progress. The default value is 10. (Since 2.7)
#
# @tls-creds: ID of the 'tls-creds' object that provides credentials
#             for establishing a TLS connection over the migration data
#             channel. On the outgoing side of the migration, the credentials
#             must be for a 'client' endpoint, while for the incoming side the
#             credentials must be for a 'server' endpoint. Setting this
#             to a non-empty string enables TLS for all migrations.
#             An empty string means that QEMU will use plain text mode for
#             migration, rather than TLS (Since 2.9)
#             Previously (since 2.7), this was reported by omitting
#             tls-creds instead.
#
# @tls-hostname: hostname of the target host for the migration. This
#                is required when using x509 based TLS credentials and the
#                migration URI does not already include a hostname. For
#                example if using fd: or exec: based migration, the
#                hostname must be provided so that the server's x509
#                certificate identity can be validated. (Since 2.7)
#                An empty string means that QEMU will use the hostname
#                associated with the migration URI, if any. (Since 2.9)
#                Previously (since 2.7), this was reported by omitting
#                tls-hostname instead.
#
# @max-bandwidth: to set maximum speed for migration. maximum speed in
#                 bytes per second. (Since 2.8)
#
# @downtime-limit: set maximum tolerated downtime for migration. maximum
#                  downtime in milliseconds (Since 2.8)
#
# @x-checkpoint-delay: the delay time between two COLO checkpoints. (Since 2.8)
#
# @block-incremental: Affects how much storage is migrated when the
#       block migration capability is enabled.  When false, the entire
#       storage backing chain is migrated into a flattened image at
#       the destination; when true, only the active qcow2 layer is
#       migrated and the destination must already have access to the
#       same backing chain as was used on the source.  (since 2.10)
#
# @x-multifd-channels: Number of channels used to migrate data in
#                     parallel. This is the same number that the
#                     number of sockets used for migration.  The
#                     default value is 2 (since 2.11)
#
# @x-multifd-page-count: Number of pages sent together to a thread.
#                        The default value is 16 (since 2.11)
#
# @xbzrle-cache-size: cache size to be used by XBZRLE migration.  It
#                     needs to be a multiple of the target page size
#                     and a power of 2
#                     (Since 2.11)
# Since: 2.4
##
# TODO either fuse back into MigrationParameters, or make
# MigrationParameters members mandatory
{ 'struct': 'MigrateSetParameters',
  'data': { '*compress-level': 'int',
            '*compress-threads': 'int',
            '*decompress-threads': 'int',
            '*cpu-throttle-initial': 'int',
            '*cpu-throttle-increment': 'int',
            '*tls-creds': 'StrOrNull',
            '*tls-hostname': 'StrOrNull',
            '*max-bandwidth': 'int',
            '*downtime-limit': 'int',
            '*x-checkpoint-delay': 'int',
            '*block-incremental': 'bool',
            '*x-multifd-channels': 'int',
            '*x-multifd-page-count': 'int',
            '*xbzrle-cache-size': 'size' } }

##
# @migrate-set-parameters:
#
# Set various migration parameters.
#
# Since: 2.4
#
# Example:
#
# -> { "execute": "migrate-set-parameters" ,
#      "arguments": { "compress-level": 1 } }
#
##
{ 'command': 'migrate-set-parameters', 'boxed': true,
  'data': 'MigrateSetParameters' }

##
# @MigrationParameters:
#
# The optional members aren't actually optional.
#
# @compress-level: compression level
#
# @compress-threads: compression thread count
#
# @decompress-threads: decompression thread count
#
# @cpu-throttle-initial: Initial percentage of time guest cpus are
#                        throttled when migration auto-converge is activated.
#                        (Since 2.7)
#
# @cpu-throttle-increment: throttle percentage increase each time
#                          auto-converge detects that migration is not making
#                          progress. (Since 2.7)
#
# @tls-creds: ID of the 'tls-creds' object that provides credentials
#             for establishing a TLS connection over the migration data
#             channel. On the outgoing side of the migration, the credentials
#             must be for a 'client' endpoint, while for the incoming side the
#             credentials must be for a 'server' endpoint.
#             An empty string means that QEMU will use plain text mode for
#             migration, rather than TLS (Since 2.7)
#             Note: 2.8 reports this by omitting tls-creds instead.
#
# @tls-hostname: hostname of the target host for the migration. This
#                is required when using x509 based TLS credentials and the
#                migration URI does not already include a hostname. For
#                example if using fd: or exec: based migration, the
#                hostname must be provided so that the server's x509
#                certificate identity can be validated. (Since 2.7)
#                An empty string means that QEMU will use the hostname
#                associated with the migration URI, if any. (Since 2.9)
#                Note: 2.8 reports this by omitting tls-hostname instead.
#
# @max-bandwidth: to set maximum speed for migration. maximum speed in
#                 bytes per second. (Since 2.8)
#
# @downtime-limit: set maximum tolerated downtime for migration. maximum
#                  downtime in milliseconds (Since 2.8)
#
# @x-checkpoint-delay: the delay time between two COLO checkpoints. (Since 2.8)
#
# @block-incremental: Affects how much storage is migrated when the
#       block migration capability is enabled.  When false, the entire
#       storage backing chain is migrated into a flattened image at
#       the destination; when true, only the active qcow2 layer is
#       migrated and the destination must already have access to the
#       same backing chain as was used on the source.  (since 2.10)
#
# @x-multifd-channels: Number of channels used to migrate data in
#                     parallel. This is the same number that the
#                     number of sockets used for migration.
#                     The default value is 2 (since 2.11)
#
# @x-multifd-page-count: Number of pages sent together to a thread.
#                        The default value is 16 (since 2.11)
#
# @xbzrle-cache-size: cache size to be used by XBZRLE migration.  It
#                     needs to be a multiple of the target page size
#                     and a power of 2
#                     (Since 2.11)
# Since: 2.4
##
{ 'struct': 'MigrationParameters',
  'data': { '*compress-level': 'uint8',
            '*compress-threads': 'uint8',
            '*decompress-threads': 'uint8',
            '*cpu-throttle-initial': 'uint8',
            '*cpu-throttle-increment': 'uint8',
            '*tls-creds': 'str',
            '*tls-hostname': 'str',
            '*max-bandwidth': 'size',
            '*downtime-limit': 'uint64',
            '*x-checkpoint-delay': 'uint32',
            '*block-incremental': 'bool' ,
            '*x-multifd-channels': 'uint8',
            '*x-multifd-page-count': 'uint32',
            '*xbzrle-cache-size': 'size' } }

##
# @query-migrate-parameters:
#
# Returns information about the current migration parameters
#
# Returns: @MigrationParameters
#
# Since: 2.4
#
# Example:
#
# -> { "execute": "query-migrate-parameters" }
# <- { "return": {
#          "decompress-threads": 2,
#          "cpu-throttle-increment": 10,
#          "compress-threads": 8,
#          "compress-level": 1,
#          "cpu-throttle-initial": 20,
#          "max-bandwidth": 33554432,
#          "downtime-limit": 300
#       }
#    }
#
##
{ 'command': 'query-migrate-parameters',
  'returns': 'MigrationParameters' }

##
# @client_migrate_info:
#
# Set migration information for remote display.  This makes the server
# ask the client to automatically reconnect using the new parameters
# once migration finished successfully.  Only implemented for SPICE.
#
# @protocol:     must be "spice"
# @hostname:     migration target hostname
# @port:         spice tcp port for plaintext channels
# @tls-port:     spice tcp port for tls-secured channels
# @cert-subject: server certificate subject
#
# Since: 0.14.0
#
# Example:
#
# -> { "execute": "client_migrate_info",
#      "arguments": { "protocol": "spice",
#                     "hostname": "virt42.lab.kraxel.org",
#                     "port": 1234 } }
# <- { "return": {} }
#
##
{ 'command': 'client_migrate_info',
  'data': { 'protocol': 'str', 'hostname': 'str', '*port': 'int',
            '*tls-port': 'int', '*cert-subject': 'str' } }

##
# @migrate-start-postcopy:
#
# Followup to a migration command to switch the migration to postcopy mode.
# The postcopy-ram capability must be set on both source and destination
# before the original migration command.
#
# Since: 2.5
#
# Example:
#
# -> { "execute": "migrate-start-postcopy" }
# <- { "return": {} }
#
##
{ 'command': 'migrate-start-postcopy' }

##
# @MIGRATION:
#
# Emitted when a migration event happens
#
# @status: @MigrationStatus describing the current migration status.
#
# Since: 2.4
#
# Example:
#
# <- {"timestamp": {"seconds": 1432121972, "microseconds": 744001},
#     "event": "MIGRATION",
#     "data": {"status": "completed"} }
#
##
{ 'event': 'MIGRATION',
  'data': {'status': 'MigrationStatus'}}

##
# @MIGRATION_PASS:
#
# Emitted from the source side of a migration at the start of each pass
# (when it syncs the dirty bitmap)
#
# @pass: An incrementing count (starting at 1 on the first pass)
#
# Since: 2.6
#
# Example:
#
# { "timestamp": {"seconds": 1449669631, "microseconds": 239225},
#   "event": "MIGRATION_PASS", "data": {"pass": 2} }
#
##
{ 'event': 'MIGRATION_PASS',
  'data': { 'pass': 'int' } }

##
# @COLOMessage:
#
# The message transmission between Primary side and Secondary side.
#
# @checkpoint-ready: Secondary VM (SVM) is ready for checkpointing
#
# @checkpoint-request: Primary VM (PVM) tells SVM to prepare for checkpointing
#
# @checkpoint-reply: SVM gets PVM's checkpoint request
#
# @vmstate-send: VM's state will be sent by PVM.
#
# @vmstate-size: The total size of VMstate.
#
# @vmstate-received: VM's state has been received by SVM.
#
# @vmstate-loaded: VM's state has been loaded by SVM.
#
# Since: 2.8
##
{ 'enum': 'COLOMessage',
  'data': [ 'checkpoint-ready', 'checkpoint-request', 'checkpoint-reply',
            'vmstate-send', 'vmstate-size', 'vmstate-received',
            'vmstate-loaded' ] }

##
# @COLOMode:
#
# The colo mode
#
# @unknown: unknown mode
#
# @primary: master side
#
# @secondary: slave side
#
# Since: 2.8
##
{ 'enum': 'COLOMode',
  'data': [ 'unknown', 'primary', 'secondary'] }

##
# @FailoverStatus:
#
# An enumeration of COLO failover status
#
# @none: no failover has ever happened
#
# @require: got failover requirement but not handled
#
# @active: in the process of doing failover
#
# @completed: finish the process of failover
#
# @relaunch: restart the failover process, from 'none' -> 'completed' (Since 2.9)
#
# Since: 2.8
##
{ 'enum': 'FailoverStatus',
  'data': [ 'none', 'require', 'active', 'completed', 'relaunch' ] }

##
# @x-colo-lost-heartbeat:
#
# Tell qemu that heartbeat is lost, request it to do takeover procedures.
# If this command is sent to the PVM, the Primary side will exit COLO mode.
# If sent to the Secondary, the Secondary side will run failover work,
# then takes over server operation to become the service VM.
#
# Since: 2.8
#
# Example:
#
# -> { "execute": "x-colo-lost-heartbeat" }
# <- { "return": {} }
#
##
{ 'command': 'x-colo-lost-heartbeat' }

##
# @migrate_cancel:
#
# Cancel the current executing migration process.
#
# Returns: nothing on success
#
# Notes: This command succeeds even if there is no migration process running.
#
# Since: 0.14.0
#
# Example:
#
# -> { "execute": "migrate_cancel" }
# <- { "return": {} }
#
##
{ 'command': 'migrate_cancel' }

##
# @migrate-continue:
#
# Continue migration when it's in a paused state.
#
# @state: The state the migration is currently expected to be in
#
# Returns: nothing on success
# Since: 2.11
# Example:
#
# -> { "execute": "migrate-continue" , "arguments":
#      { "state": "pre-switchover" } }
# <- { "return": {} }
##
{ 'command': 'migrate-continue', 'data': {'state': 'MigrationStatus'} }

##
# @migrate_set_downtime:
#
# Set maximum tolerated downtime for migration.
#
# @value: maximum downtime in seconds
#
# Returns: nothing on success
#
# Notes: This command is deprecated in favor of 'migrate-set-parameters'
#
# Since: 0.14.0
#
# Example:
#
# -> { "execute": "migrate_set_downtime", "arguments": { "value": 0.1 } }
# <- { "return": {} }
#
##
{ 'command': 'migrate_set_downtime', 'data': {'value': 'number'} }

##
# @migrate_set_speed:
#
# Set maximum speed for migration.
#
# @value: maximum speed in bytes per second.
#
# Returns: nothing on success
#
# Notes: This command is deprecated in favor of 'migrate-set-parameters'
#
# Since: 0.14.0
#
# Example:
#
# -> { "execute": "migrate_set_speed", "arguments": { "value": 1024 } }
# <- { "return": {} }
#
##
{ 'command': 'migrate_set_speed', 'data': {'value': 'int'} }

##
# @migrate-set-cache-size:
#
# Set cache size to be used by XBZRLE migration
#
# @value: cache size in bytes
#
# The size will be rounded down to the nearest power of 2.
# The cache size can be modified before and during ongoing migration
#
# Returns: nothing on success
#
# Notes: This command is deprecated in favor of 'migrate-set-parameters'
#
# Since: 1.2
#
# Example:
#
# -> { "execute": "migrate-set-cache-size",
#      "arguments": { "value": 536870912 } }
# <- { "return": {} }
#
##
{ 'command': 'migrate-set-cache-size', 'data': {'value': 'int'} }

##
# @query-migrate-cache-size:
#
# Query migration XBZRLE cache size
#
# Returns: XBZRLE cache size in bytes
#
# Notes: This command is deprecated in favor of 'query-migrate-parameters'
#
# Since: 1.2
#
# Example:
#
# -> { "execute": "query-migrate-cache-size" }
# <- { "return": 67108864 }
#
##
{ 'command': 'query-migrate-cache-size', 'returns': 'int' }

##
# @migrate:
#
# Migrates the current running guest to another Virtual Machine.
#
# @uri: the Uniform Resource Identifier of the destination VM
#
# @blk: do block migration (full disk copy)
#
# @inc: incremental disk copy migration
#
# @detach: this argument exists only for compatibility reasons and
#          is ignored by QEMU
#
# Returns: nothing on success
#
# Since: 0.14.0
#
# Notes:
#
# 1. The 'query-migrate' command should be used to check migration's progress
#    and final result (this information is provided by the 'status' member)
#
# 2. All boolean arguments default to false
#
# 3. The user Monitor's "detach" argument is invalid in QMP and should not
#    be used
#
# Example:
#
# -> { "execute": "migrate", "arguments": { "uri": "tcp:0:4446" } }
# <- { "return": {} }
#
##
{ 'command': 'migrate',
  'data': {'uri': 'str', '*blk': 'bool', '*inc': 'bool', '*detach': 'bool' } }

##
# @migrate-incoming:
#
# Start an incoming migration, the qemu must have been started
# with -incoming defer
#
# @uri: The Uniform Resource Identifier identifying the source or
#       address to listen on
#
# Returns: nothing on success
#
# Since: 2.3
#
# Notes:
#
# 1. It's a bad idea to use a string for the uri, but it needs to stay
#    compatible with -incoming and the format of the uri is already exposed
#    above libvirt.
#
# 2. QEMU must be started with -incoming defer to allow migrate-incoming to
#    be used.
#
# 3. The uri format is the same as for -incoming
#
# Example:
#
# -> { "execute": "migrate-incoming",
#      "arguments": { "uri": "tcp::4446" } }
# <- { "return": {} }
#
##
{ 'command': 'migrate-incoming', 'data': {'uri': 'str' } }

##
# @xen-save-devices-state:
#
# Save the state of all devices to file. The RAM and the block devices
# of the VM are not saved by this command.
#
# @filename: the file to save the state of the devices to as binary
# data. See xen-save-devices-state.txt for a description of the binary
# format.
#
# @live: Optional argument to ask QEMU to treat this command as part of a live
# migration. Default to true. (since 2.11)
#
# Returns: Nothing on success
#
# Since: 1.1
#
# Example:
#
# -> { "execute": "xen-save-devices-state",
#      "arguments": { "filename": "/tmp/save" } }
# <- { "return": {} }
#
##
{ 'command': 'xen-save-devices-state',
  'data': {'filename': 'str', '*live':'bool' } }

##
# @xen-set-replication:
#
# Enable or disable replication.
#
# @enable: true to enable, false to disable.
#
# @primary: true for primary or false for secondary.
#
# @failover: true to do failover, false to stop. but cannot be
#            specified if 'enable' is true. default value is false.
#
# Returns: nothing.
#
# Example:
#
# -> { "execute": "xen-set-replication",
#      "arguments": {"enable": true, "primary": false} }
# <- { "return": {} }
#
# Since: 2.9
##
{ 'command': 'xen-set-replication',
  'data': { 'enable': 'bool', 'primary': 'bool', '*failover' : 'bool' } }

##
# @ReplicationStatus:
#
# The result format for 'query-xen-replication-status'.
#
# @error: true if an error happened, false if replication is normal.
#
# @desc: the human readable error description string, when
#        @error is 'true'.
#
# Since: 2.9
##
{ 'struct': 'ReplicationStatus',
  'data': { 'error': 'bool', '*desc': 'str' } }

##
# @query-xen-replication-status:
#
# Query replication status while the vm is running.
#
# Returns: A @ReplicationResult object showing the status.
#
# Example:
#
# -> { "execute": "query-xen-replication-status" }
# <- { "return": { "error": false } }
#
# Since: 2.9
##
{ 'command': 'query-xen-replication-status',
  'returns': 'ReplicationStatus' }

##
# @xen-colo-do-checkpoint:
#
# Xen uses this command to notify replication to trigger a checkpoint.
#
# Returns: nothing.
#
# Example:
#
# -> { "execute": "xen-colo-do-checkpoint" }
# <- { "return": {} }
#
# Since: 2.9
##
{ 'command': 'xen-colo-do-checkpoint' }