REST Resource: instanceGroupManagers

Resource: InstanceGroupManager

Represents a Managed Instance Group resource.

An instance group is a collection of VM instances that you can manage as a single entity. For more information, read Instance groups.

For zonal Managed Instance Group, use the instanceGroupManagers resource.

For regional Managed Instance Group, use the regionInstanceGroupManagers resource.

JSON representation 
{
  "kind": string,
  "id": string,
  "creationTimestamp": string,
  "name": string,
  "description": string,
  "zone": string,
  "region": string,
  "distributionPolicy": {
    "zones": [
      {
        "zone": string
      }
    ],
    "targetShape": enum
  },
  "instanceTemplate": string,
  "versions": [
    {
      "name": string,
      "instanceTemplate": string,
      "targetSize": {
        "fixed": integer,
        "percent": integer,
        "calculated": integer
      }
    }
  ],
  "allInstancesConfig": {
    "properties": {
      "metadata": {
        string: string,
        ...
      },
      "labels": {
        string: string,
        ...
      }
    }
  },
  "instanceGroup": string,
  "targetPools": [
    string
  ],
  "baseInstanceName": string,
  "fingerprint": string,
  "currentActions": {
    "none": integer,
    "creating": integer,
    "creatingWithoutRetries": integer,
    "verifying": integer,
    "recreating": integer,
    "deleting": integer,
    "abandoning": integer,
    "restarting": integer,
    "refreshing": integer,
    "suspending": integer,
    "resuming": integer,
    "stopping": integer,
    "starting": integer
  },
  "status": {
    "isStable": boolean,
    "allInstancesConfig": {
      "effective": boolean,
      "currentRevision": string
    },
    "versionTarget": {
      "isReached": boolean
    },
    "stateful": {
      "hasStatefulConfig": boolean,
      "perInstanceConfigs": {
        "allEffective": boolean
      }
    },
    "autoscaler": string
  },
  "targetSize": integer,
  "instanceFlexibilityPolicy": {
    "instanceSelections": {
      string: {
        "machineTypes": [
          string
        ],
        "rank": integer
      },
      ...
    }
  },
  "targetStoppedSize": integer,
  "targetSuspendedSize": integer,
  "listManagedInstancesResults": enum,
  "standbyPolicy": {
    "initialDelaySec": integer,
    "mode": enum
  },
  "selfLink": string,
  "autoHealingPolicies": [
    {
      "healthCheck": string,
      "initialDelaySec": integer
    }
  ],
  "updatePolicy": {
    "type": enum,
    "instanceRedistributionType": enum,
    "minimalAction": enum,
    "mostDisruptiveAllowedAction": enum,
    "maxSurge": {
      "fixed": integer,
      "percent": integer,
      "calculated": integer
    },
    "maxUnavailable": {
      "fixed": integer,
      "percent": integer,
      "calculated": integer
    },
    "replacementMethod": enum
  },
  "namedPorts": [
    {
      "name": string,
      "port": integer
    }
  ],
  "statefulPolicy": {
    "preservedState": {
      "disks": {
        string: {
          "autoDelete": enum
        },
        ...
      },
      "internalIPs": {
        string: {
          "autoDelete": enum
        },
        ...
      },
      "externalIPs": {
        string: {
          "autoDelete": enum
        },
        ...
      }
    }
  },
  "instanceLifecyclePolicy": {
    "forceUpdateOnRepair": enum,
    "defaultActionOnFailure": enum
  },
  "satisfiesPzi": boolean,
  "satisfiesPzs": boolean
}
Fields
kind

string

[Output Only] The resource type, which is always compute#instanceGroupManager for managed instance groups.
id

string (uint64 format)

[Output Only] A unique identifier for this resource type. The server generates this identifier.
creationTimestamp

string

[Output Only] The creation timestamp for this managed instance group in RFC3339 text format.
name

string

The name of the managed instance group. The name must be 1-63 characters long, and comply with RFC1035.
description

string

An optional description of this resource.
zone

string

[Output Only] The URL of a zone where the managed instance group is located (for zonal resources).
region

string

[Output Only] The URL of the region where the managed instance group resides (for regional resources).
distributionPolicy

object

Policy specifying the intended distribution of managed instances across zones in a regional managed instance group.
distributionPolicy.zones[]

object

Zones where the regional managed instance group will create and manage its instances.
distributionPolicy.zones[].zone

string

The URL of the zone. The zone must exist in the region where the managed instance group is located.
distributionPolicy.targetShape

enum

The distribution shape to which the group converges either proactively or on resize events (depending on the value set in updatePolicy.instanceRedistributionType).
instanceTemplate

string

The URL of the instance template that is specified for this managed instance group. The group uses this template to create all new instances in the managed instance group. The templates for existing instances in the group do not change unless you run recreateInstances, run applyUpdatesToInstances, or set the group's updatePolicy.type to PROACTIVE.
versions[]

object

Specifies the instance templates used by this managed instance group to create instances.

Each version is defined by an instanceTemplate and a name. Every version can appear at most once per instance group. This field overrides the top-level instanceTemplate field. Read more about the relationships between these fields. Exactly one version must leave the targetSize field unset. That version will be applied to all remaining instances. For more information, read about canary updates.
versions[].name

string

Name of the version. Unique among all versions in the scope of this managed instance group.
versions[].instanceTemplate

string

The URL of the instance template that is specified for this managed instance group. The group uses this template to create new instances in the managed instance group until the targetSize for this version is reached. The templates for existing instances in the group do not change unless you run recreateInstances, run applyUpdatesToInstances, or set the group's updatePolicy.type to PROACTIVE; in those cases, existing instances are updated until the targetSize for this version is reached.
versions[].targetSize

object

Specifies the intended number of instances to be created from the instanceTemplate. The final number of instances created from the template will be equal to:

  • If expressed as a fixed number, the minimum of either targetSize.fixed or instanceGroupManager.targetSize is used.
  • if expressed as a percent, the targetSize would be (targetSize.percent/100 * InstanceGroupManager.targetSize) If there is a remainder, the number is rounded.
If unset, this version will update any remaining instances not updated by another version. Read Starting a canary update for more information.
versions[].targetSize.fixed

integer

Specifies a fixed number of VM instances. This must be a positive integer.
versions[].targetSize.percent

integer

Specifies a percentage of instances between 0 to 100%, inclusive. For example, specify 80 for 80%.
versions[].targetSize.calculated

integer

[Output Only] Absolute value of VM instances calculated based on the specific mode.

  • If the value is fixed, then the calculated value is equal to the fixed value.
  • If the value is a percent, then the calculated value is percent/100 * targetSize. For example, the calculated value of a 80% of a managed instance group with 150 instances would be (80/100 * 150) = 120 VM instances. If there is a remainder, the number is rounded.
allInstancesConfig

object

Specifies configuration that overrides the instance template configuration for the group.
allInstancesConfig.properties

object

Properties to set on all instances in the group.

You can add or modify properties using the instanceGroupManagers.patch or regionInstanceGroupManagers.patch. After setting allInstancesConfig on the group, you must update the group's instances to apply the configuration. To apply the configuration, set the group's updatePolicy.type field to use proactive updates or use the applyUpdatesToInstances method.
allInstancesConfig.properties.metadata

map (key: string, value: string)

The metadata key-value pairs that you want to patch onto the instance. For more information, see Project and instance metadata.
allInstancesConfig.properties.labels

map (key: string, value: string)

The label key-value pairs that you want to patch onto the instance.
instanceGroup

string

[Output Only] The URL of the Instance Group resource.
targetPools[]

string

The URLs for all TargetPool resources to which instances in the instanceGroup field are added. The target pools automatically apply to all of the instances in the managed instance group.
baseInstanceName

string

The base instance name is a prefix that you want to attach to the names of all VMs in a MIG. The maximum character length is 58 and the name must comply with RFC1035 format.

When a VM is created in the group, the MIG appends a hyphen and a random four-character string to the base instance name. If you want the MIG to assign sequential numbers instead of a random string, then end the base instance name with a hyphen followed by one or more hash symbols. The hash symbols indicate the number of digits. For example, a base instance name of "vm-###" results in "vm-001" as a VM name. @pattern [a-z](([-a-z0-9]{0,57})|([-a-z0-9]{0,51}-#{1,10}(\[[0-9]{1,10}\])?))
fingerprint

string (bytes format)

Fingerprint of this resource. This field may be used in optimistic locking. It will be ignored when inserting an InstanceGroupManager. An up-to-date fingerprint must be provided in order to update the InstanceGroupManager, otherwise the request will fail with error 412 conditionNotMet.

To see the latest fingerprint, make a get() request to retrieve an InstanceGroupManager.

A base64-encoded string.
currentActions

object

[Output Only] The list of instance actions and the number of instances in this managed instance group that are scheduled for each of those actions.
currentActions.none

integer

[Output Only] The number of instances in the managed instance group that are running and have no scheduled actions.
currentActions.creating

integer

[Output Only] The number of instances in the managed instance group that are scheduled to be created or are currently being created. If the group fails to create any of these instances, it tries again until it creates the instance successfully.

If you have disabled creation retries, this field will not be populated; instead, the creatingWithoutRetries field will be populated.
currentActions.creatingWithoutRetries

integer

[Output Only] The number of instances that the managed instance group will attempt to create. The group attempts to create each instance only once. If the group fails to create any of these instances, it decreases the group's targetSize value accordingly.
currentActions.verifying

integer

[Output Only] The number of instances in the managed instance group that are being verified. See the managedInstances[].currentAction property in the listManagedInstances method documentation.
currentActions.recreating

integer

[Output Only] The number of instances in the managed instance group that are scheduled to be recreated or are currently being being recreated. Recreating an instance deletes the existing root persistent disk and creates a new disk from the image that is defined in the instance template.
currentActions.deleting

integer

[Output Only] The number of instances in the managed instance group that are scheduled to be deleted or are currently being deleted.
currentActions.abandoning

integer

[Output Only] The total number of instances in the managed instance group that are scheduled to be abandoned. Abandoning an instance removes it from the managed instance group without deleting it.
currentActions.restarting

integer

[Output Only] The number of instances in the managed instance group that are scheduled to be restarted or are currently being restarted.
currentActions.refreshing

integer

[Output Only] The number of instances in the managed instance group that are being reconfigured with properties that do not require a restart or a recreate action. For example, setting or removing target pools for the instance.
currentActions.suspending

integer

[Output Only] The number of instances in the managed instance group that are scheduled to be suspended or are currently being suspended.
currentActions.resuming

integer

[Output Only] The number of instances in the managed instance group that are scheduled to be resumed or are currently being resumed.
currentActions.stopping

integer

[Output Only] The number of instances in the managed instance group that are scheduled to be stopped or are currently being stopped.
currentActions.starting

integer

[Output Only] The number of instances in the managed instance group that are scheduled to be started or are currently being started.
status

object

[Output Only] The status of this managed instance group.
status.isStable

boolean

[Output Only] A bit indicating whether the managed instance group is in a stable state. A stable state means that: none of the instances in the managed instance group is currently undergoing any type of change (for example, creation, restart, or deletion); no future changes are scheduled for instances in the managed instance group; and the managed instance group itself is not being modified.
status.allInstancesConfig

object

[Output only] Status of all-instances configuration on the group.
status.allInstancesConfig.effective

boolean

[Output Only] A bit indicating whether this configuration has been applied to all managed instances in the group.
status.allInstancesConfig.currentRevision

string

[Output Only] Current all-instances configuration revision. This value is in RFC3339 text format.
status.versionTarget

object

[Output Only] A status of consistency of Instances' versions with their target version specified by version field on Instance Group Manager.
status.versionTarget.isReached

boolean

[Output Only] A bit indicating whether version target has been reached in this managed instance group, i.e. all instances are in their target version. Instances' target version are specified by version field on Instance Group Manager.
status.stateful

object

[Output Only] Stateful status of the given Instance Group Manager.
status.stateful.hasStatefulConfig

boolean

[Output Only] A bit indicating whether the managed instance group has stateful configuration, that is, if you have configured any items in a stateful policy or in per-instance configs. The group might report that it has no stateful configuration even when there is still some preserved state on a managed instance, for example, if you have deleted all PICs but not yet applied those deletions.
status.stateful.perInstanceConfigs

object

[Output Only] Status of per-instance configurations on the instances.
status.stateful.perInstanceConfigs.allEffective

boolean

A bit indicating if all of the group's per-instance configurations (listed in the output of a listPerInstanceConfigs API call) have status EFFECTIVE or there are no per-instance-configs.
status.autoscaler

string

[Output Only] The URL of the Autoscaler that targets this instance group manager.
targetSize

integer

The target number of running instances for this managed instance group. You can reduce this number by using the instanceGroupManager deleteInstances or abandonInstances methods. Resizing the group also changes this number.
instanceFlexibilityPolicy

object

Instance flexibility allowing MIG to create VMs from multiple types of machines. Instance flexibility configuration on MIG overrides instance template configuration.
instanceFlexibilityPolicy.instanceSelections[]

map (key: string, value: object)

Named instance selections configuring properties that the group will use when creating new VMs.
instanceFlexibilityPolicy.instanceSelections[].machineTypes[]

string

Full machine-type names, e.g. "n1-standard-16".
instanceFlexibilityPolicy.instanceSelections[].rank

integer

Preference of this instance selection. Lower number means higher preference. MIG will first try to create a VM based on the machine-type with lowest rank and fallback to next rank based on availability. Machine types and instance selections with the same rank have the same preference.
targetStoppedSize

integer

The target number of stopped instances for this managed instance group. This number changes when you:

targetSuspendedSize

integer

The target number of suspended instances for this managed instance group. This number changes when you:

listManagedInstancesResults

enum

Pagination behavior of the listManagedInstances API method for this managed instance group.
standbyPolicy

object

Standby policy for stopped and suspended instances.
standbyPolicy.initialDelaySec

integer

Specifies the number of seconds that the MIG should wait to suspend or stop a VM after that VM was created. The initial delay gives the initialization script the time to prepare your VM for a quick scale out. The value of initial delay must be between 0 and 3600 seconds. The default value is 0.
standbyPolicy.mode

enum

Defines how a MIG resumes or starts VMs from a standby pool when the group scales out. The default mode is MANUAL.
autoHealingPolicies[]

object

The autohealing policy for this managed instance group. You can specify only one value.
autoHealingPolicies[].healthCheck

string

The URL for the health check that signals autohealing.
autoHealingPolicies[].initialDelaySec

integer

The initial delay is the number of seconds that a new VM takes to initialize and run its startup script. During a VM's initial delay period, the MIG ignores unsuccessful health checks because the VM might be in the startup process. This prevents the MIG from prematurely recreating a VM. If the health check receives a healthy response during the initial delay, it indicates that the startup process is complete and the VM is ready. The value of initial delay must be between 0 and 3600 seconds. The default value is 0.
updatePolicy

object

The update policy for this managed instance group.
updatePolicy.type

enum

The type of update process. You can specify either PROACTIVE so that the MIG automatically updates VMs to the latest configurations or OPPORTUNISTIC so that you can select the VMs that you want to update.
updatePolicy.instanceRedistributionType

enum

The instance redistribution policy for regional managed instance groups. Valid values are:

  • PROACTIVE (default): The group attempts to maintain an even distribution of VM instances across zones in the region.
  • NONE: For non-autoscaled groups, proactive redistribution is disabled.
updatePolicy.minimalAction

enum

Minimal action to be taken on an instance. Use this option to minimize disruption as much as possible or to apply a more disruptive action than is necessary.

  • To limit disruption as much as possible, set the minimal action to REFRESH. If your update requires a more disruptive action, Compute Engine performs the necessary action to execute the update.
  • To apply a more disruptive action than is strictly necessary, set the minimal action to RESTART or REPLACE. For example, Compute Engine does not need to restart a VM to change its metadata. But if your application reads instance metadata only when a VM is restarted, you can set the minimal action to RESTART in order to pick up metadata changes.
updatePolicy.mostDisruptiveAllowedAction

enum

Most disruptive action that is allowed to be taken on an instance. You can specify either NONE to forbid any actions, REFRESH to avoid restarting the VM and to limit disruption as much as possible. RESTART to allow actions that can be applied without instance replacing or REPLACE to allow all possible actions. If the Updater determines that the minimal update action needed is more disruptive than most disruptive allowed action you specify it will not perform the update at all.
updatePolicy.maxSurge

object

The maximum number of instances that can be created above the specified targetSize during the update process. This value can be either a fixed number or, if the group has 10 or more instances, a percentage. If you set a percentage, the number of instances is rounded if necessary. The default value for maxSurge is a fixed value equal to the number of zones in which the managed instance group operates.

At least one of either maxSurge or maxUnavailable must be greater than 0. Learn more about maxSurge.
updatePolicy.maxSurge.fixed

integer

Specifies a fixed number of VM instances. This must be a positive integer.
updatePolicy.maxSurge.percent

integer

Specifies a percentage of instances between 0 to 100%, inclusive. For example, specify 80 for 80%.
updatePolicy.maxSurge.calculated

integer

[Output Only] Absolute value of VM instances calculated based on the specific mode.

  • If the value is fixed, then the calculated value is equal to the fixed value.
  • If the value is a percent, then the calculated value is percent/100 * targetSize. For example, the calculated value of a 80% of a managed instance group with 150 instances would be (80/100 * 150) = 120 VM instances. If there is a remainder, the number is rounded.
updatePolicy.maxUnavailable

object

The maximum number of instances that can be unavailable during the update process. An instance is considered available if all of the following conditions are satisfied:

  • The instance's status is RUNNING.
  • If there is a health check on the instance group, the instance's health check status must be HEALTHY at least once. If there is no health check on the group, then the instance only needs to have a status of RUNNING to be considered available.

This value can be either a fixed number or, if the group has 10 or more instances, a percentage. If you set a percentage, the number of instances is rounded if necessary. The default value for maxUnavailable is a fixed value equal to the number of zones in which the managed instance group operates.

At least one of either maxSurge or maxUnavailable must be greater than 0. Learn more about maxUnavailable.
updatePolicy.maxUnavailable.fixed

integer

Specifies a fixed number of VM instances. This must be a positive integer.
updatePolicy.maxUnavailable.percent

integer

Specifies a percentage of instances between 0 to 100%, inclusive. For example, specify 80 for 80%.
updatePolicy.maxUnavailable.calculated

integer

[Output Only] Absolute value of VM instances calculated based on the specific mode.

  • If the value is fixed, then the calculated value is equal to the fixed value.
  • If the value is a percent, then the calculated value is percent/100 * targetSize. For example, the calculated value of a 80% of a managed instance group with 150 instances would be (80/100 * 150) = 120 VM instances. If there is a remainder, the number is rounded.
updatePolicy.replacementMethod

enum

What action should be used to replace instances. See minimalAction.REPLACE
namedPorts[]

object

[Output Only] Named ports configured on the Instance Groups complementary to this Instance Group Manager.
namedPorts[].name

string

The name for this named port. The name must be 1-63 characters long, and comply with RFC1035.
namedPorts[].port

integer

The port number, which can be a value between 1 and 65535.
statefulPolicy

object

Stateful configuration for this Instanced Group Manager
statefulPolicy.preservedState

object
statefulPolicy.preservedState.disks[]

map (key: string, value: object)

Disks created on the instances that will be preserved on instance delete, update, etc. This map is keyed with the device names of the disks.
statefulPolicy.preservedState.disks[].autoDelete

enum

These stateful disks will never be deleted during autohealing, update or VM instance recreate operations. This flag is used to configure if the disk should be deleted after it is no longer used by the group, e.g. when the given instance or the whole group is deleted. Note: disks attached in READ_ONLY mode cannot be auto-deleted.
statefulPolicy.preservedState.internalIPs[]

map (key: string, value: object)

Internal network IPs assigned to the instances that will be preserved on instance delete, update, etc. This map is keyed with the network interface name.
statefulPolicy.preservedState.internalIPs[].autoDelete

enum

These stateful IPs will never be released during autohealing, update or VM instance recreate operations. This flag is used to configure if the IP reservation should be deleted after it is no longer used by the group, e.g. when the given instance or the whole group is deleted.
statefulPolicy.preservedState.externalIPs[]

map (key: string, value: object)

External network IPs assigned to the instances that will be preserved on instance delete, update, etc. This map is keyed with the network interface name.
statefulPolicy.preservedState.externalIPs[].autoDelete

enum

These stateful IPs will never be released during autohealing, update or VM instance recreate operations. This flag is used to configure if the IP reservation should be deleted after it is no longer used by the group, e.g. when the given instance or the whole group is deleted.
instanceLifecyclePolicy

object

The repair policy for this managed instance group.
instanceLifecyclePolicy.forceUpdateOnRepair

enum

A bit indicating whether to forcefully apply the group's latest configuration when repairing a VM. Valid options are:

  • NO (default): If configuration updates are available, they are not forcefully applied during repair. Instead, configuration updates are applied according to the group's update policy.
  • YES: If configuration updates are available, they are applied during repair.
instanceLifecyclePolicy.defaultActionOnFailure

enum

The action that a MIG performs on a failed or an unhealthy VM. A VM is marked as unhealthy when the application running on that VM fails a health check. Valid values are

  • REPAIR (default): MIG automatically repairs a failed or an unhealthy VM by recreating it. For more information, see About repairing VMs in a MIG.
  • DO_NOTHING: MIG does not repair a failed or an unhealthy VM.
satisfiesPzi

boolean

[Output Only] Reserved for future use.
satisfiesPzs

boolean

[Output Only] Reserved for future use.

Methods

abandonInstances

 Flags the specified instances to be removed from the managed instance group.

aggregatedList

 Retrieves the list of managed instance groups and groups them by zone.

applyUpdatesToInstances

 Applies changes to selected instances on the managed instance group.

createInstances

 Creates instances with per-instance configurations in this managed instance group.

delete

 Deletes the specified managed instance group and all of the instances in that group.

deleteInstances

 Flags the specified instances in the managed instance group for immediate deletion.

deletePerInstanceConfigs

 Deletes selected per-instance configurations for the managed instance group.

get

 Returns all of the details about the specified managed instance group.

insert

 Creates a managed instance group using the information that you specify in the request.

list

 Retrieves a list of managed instance groups that are contained within the specified project and zone.

listErrors

 Lists all errors thrown by actions on instances for a given managed instance group.

listManagedInstances

 Lists all of the instances in the managed instance group.

listPerInstanceConfigs

 Lists all of the per-instance configurations defined for the managed instance group.

patch

 Updates a managed instance group using the information that you specify in the request.

patchPerInstanceConfigs

 Inserts or patches per-instance configurations for the managed instance group.

recreateInstances

 Flags the specified VM instances in the managed instance group to be immediately recreated.

resize

 Resizes the managed instance group.

resumeInstances

 Flags the specified instances in the managed instance group to be resumed.

setInstanceTemplate

 Specifies the instance template to use when creating new instances in this group.

setTargetPools

 Modifies the target pools to which all instances in this managed instance group are assigned.

startInstances

 Flags the specified instances in the managed instance group to be started.

stopInstances

 Flags the specified instances in the managed instance group to be immediately stopped.

suspendInstances

 Flags the specified instances in the managed instance group to be immediately suspended.

updatePerInstanceConfigs

 Inserts or updates per-instance configurations for the managed instance group.