InstanceGroupManagers

Represents an Instance Group Manager resource, which creates and manages groups of identical virtual machine instances for you, using a shared instance template. Read Creating groups of instances for more information.

For a list of methods for this resource, see the end of this page.

Resource representations

An Instance Group Manager resource.

{
  "kind": "compute#instanceGroupManager",
  "id": unsigned long,
  "creationTimestamp": string,
  "name": string,
  "description": string,
  "zone": string,
  "region": string,
  "instanceTemplate": string,
  "versions": [
    {
      "name": string,
      "instanceTemplate": string,
      "targetSize": {
        "fixed": integer,
        "percent": integer,
        "calculated": integer
      }
    }
  ],
  "instanceGroup": string,
  "targetPools": [
    string
  ],
  "baseInstanceName": string,
  "fingerprint": bytes,
  "currentActions": {
    "none": integer,
    "creating": integer,
    "creatingWithoutRetries": integer,
    "verifying": integer,
    "recreating": integer,
    "deleting": integer,
    "abandoning": integer,
    "restarting": integer,
    "refreshing": integer
  },
  "pendingActions": {
    "creating": integer,
    "deleting": integer,
    "recreating": integer,
    "restarting": integer
  },
  "targetSize": integer,
  "selfLink": string,
  "autoHealingPolicies": [
    {
      "healthCheck": string,
      "initialDelaySec": integer
    }
  ],
  "updatePolicy": {
    "type": string,
    "minimalAction": string,
    "maxSurge": {
      "fixed": integer,
      "percent": integer,
      "calculated": integer
    },
    "maxUnavailable": {
      "fixed": integer,
      "percent": integer,
      "calculated": integer
    },
    "minReadySec": integer
  },
  "namedPorts": [
    {
      "name": string,
      "port": integer
    }
  ],
  "serviceAccount": string,
  "failoverAction": string
}
Property name Value Description Notes
autoHealingPolicies[] list 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 number of seconds that the managed instance group waits before it applies autohealing policies to new instances or recently recreated instances. This initial delay allows instances to initialize and run their startup scripts before the instance group determines that they are UNHEALTHY. This prevents the managed instance group from recreating its instances prematurely. This value must be from range [0, 3600].
baseInstanceName string The base instance name to use for instances in this group. The value must be 1-58 characters long. Instances are named by appending a hyphen and a random four-character string to the base instance name. The base instance name must comply with RFC1035.
creationTimestamp string [Output Only] The creation timestamp for this managed instance group in RFC3339 text format.
currentActions nested 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.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.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.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.none integer [Output Only] The number of instances in the managed instance group that are running and have no scheduled actions.
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.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.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.verifying integer [Output Only] The number of instances in the managed instance group that are being verified. More details regarding verification process are covered in the documentation of ManagedInstance.InstanceAction.VERIFYING enum field.
description string An optional description of this resource. Provide this property when you create the resource.
failoverAction string The action to perform in case of zone failure. Only one value is supported, NO_FAILOVER. The default is NO_FAILOVER.
fingerprint bytes [Output Only] The fingerprint of the resource data. You can use this optional field for optimistic locking when you update the resource.
id unsigned long [Output Only] A unique identifier for this resource type. The server generates this identifier.
instanceGroup string [Output Only] The URL of the Instance Group resource.
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.
kind string [Output Only] The resource type, which is always compute#instanceGroupManager for managed instance groups.
name string The name of the managed instance group. The name must be 1-63 characters long, and comply with RFC1035.
namedPorts[] list Named ports configured for 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.
pendingActions nested object [Output Only] The list of instance actions and the number of instances in this managed instance group that are pending for each of those actions.
pendingActions.creating integer [Output Only] The number of instances in the managed instance group that are pending to be created.
pendingActions.deleting integer [Output Only] The number of instances in the managed instance group that are pending to be deleted.
pendingActions.recreating integer [Output Only] The number of instances in the managed instance group that are pending to be recreated.
pendingActions.restarting integer [Output Only] The number of instances in the managed instance group that are pending to be restarted.
region string [Output Only] The URL of the region where the managed instance group resides (for regional resources).
serviceAccount string [Output Only] The service account to be used as credentials for all operations performed by the managed instance group on instances. The service accounts needs all permissions required to create and delete instances. By default, the service account {projectNumber}@cloudservices.gserviceaccount.com is used.
targetPools[] list 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.
targetSize integer The target number of running instances for this managed instance group. Deleting or abandoning instances reduces this number. Resizing the group changes this number.
updatePolicy nested object The update policy for this managed instance group.
updatePolicy.maxSurge nested object The maximum number of instances that can be created above the specified targetSize during the update process. By default, a fixed value of 1 is used. This value can be either a fixed number or a percentage if the instance group has 10 or more instances. If you set a percentage, the number of instances will be rounded up if necessary.

At least one of either maxSurge or maxUnavailable must be greater than 0. Learn more about maxSurge.
updatePolicy.maxSurge.calculated integer [Output Only] Absolute value of VM instances calculated based on the specific mode.

  • If the value is fixed, then the caculated 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 up.
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.maxUnavailable nested 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 grourp, the instance's liveness health check result 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.
By default, a fixed value of 1 is used. This value can be either a fixed number or a percentage if the instance group has 10 or more instances. If you set a percentage, the number of instances will be rounded up if necessary.

At least one of either maxSurge or maxUnavailable must be greater than 0. Learn more about maxUnavailable.
updatePolicy.maxUnavailable.calculated integer [Output Only] Absolute value of VM instances calculated based on the specific mode.

  • If the value is fixed, then the caculated 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 up.
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.minReadySec integer Minimum number of seconds to wait for after a newly created instance becomes available. This value must be from range [0, 3600].
updatePolicy.minimalAction string Minimal action to be taken on an instance. You can specify either RESTART to restart existing instances or REPLACE to delete and create new instances from the target template. If you specify a code>RESTART, the Updater will attempt to perform that action only. However, if the Updater determines that the minimal action you specify is not enough to perform the update, it might perform a more disruptive action.
updatePolicy.type string
versions[] list Specifies the instance templates used by this managed instance group to create instances.

Each version is defined by an instanceTemplate. Every template 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[].instanceTemplate string
versions[].name string Name of the version. Unique among all versions in the scope of this managed instance group.
versions[].targetSize nested 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 up.
If unset, this version will update any remaining instances not updated by another version. Read Starting a canary update for more information.
versions[].targetSize.calculated integer [Output Only] Absolute value of VM instances calculated based on the specific mode.

  • If the value is fixed, then the caculated 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 up.
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%.
zone string [Output Only] The URL of the zone where the managed instance group is located (for zonal resources).

Methods

abandonInstances
Schedules a group action to remove the specified instances from the managed instance group. Abandoning an instance does not delete the instance, but it does remove the instance from any target pools that are applied by the managed instance group. This method reduces the targetSize of the managed instance group by the number of instances that you abandon. This operation is marked as DONE when the action is scheduled even if the instances have not yet been removed from the group. You must separately verify the status of the abandoning action with the listmanagedinstances method.

If the group is part of a backend service that has enabled connection draining, it can take up to 60 seconds after the connection draining duration has elapsed before the VM instance is removed or deleted.

You can specify a maximum of 1000 instances with this method per request.
aggregatedList
Retrieves the list of managed instance groups and groups them by zone.
delete
Deletes the specified managed instance group and all of the instances in that group. Note that the instance group must not belong to a backend service. Read Deleting an instance group for more information.
deleteInstances
Schedules a group action to delete the specified instances in the managed instance group. The instances are also removed from any target pools of which they were a member. This method reduces the targetSize of the managed instance group by the number of instances that you delete. This operation is marked as DONE when the action is scheduled even if the instances are still being deleted. You must separately verify the status of the deleting action with the listmanagedinstances method.

If the group is part of a backend service that has enabled connection draining, it can take up to 60 seconds after the connection draining duration has elapsed before the VM instance is removed or deleted.

You can specify a maximum of 1000 instances with this method per request.
get
Returns all of the details about the specified managed instance group. Get a list of available managed instance groups by making a list() request.
insert
Creates a managed instance group using the information that you specify in the request. After the group is created, it schedules an action to create instances in the group using the specified instance template. This operation is marked as DONE when the group is created even if the instances in the group have not yet been created. You must separately verify the status of the individual instances with the listmanagedinstances method.

A managed instance group can have up to 1000 VM instances per group. Please contact Cloud Support if you need an increase in this limit.
list
Retrieves a list of managed instance groups that are contained within the specified project and zone.
listManagedInstances
Lists all of the instances in the managed instance group. Each instance in the list has a currentAction, which indicates the action that the managed instance group is performing on the instance. For example, if the group is still creating an instance, the currentAction is CREATING. If a previous action failed, the list displays the errors for that failed action.
patch
Updates a managed instance group using the information that you specify in the request. This operation is marked as DONE when the group is patched even if the instances in the group are still in the process of being patched. You must separately verify the status of the individual instances with the listManagedInstances method. This method supports PATCH semantics and uses the JSON merge patch format and processing rules.
recreateInstances
Schedules a group action to recreate the specified instances in the managed instance group. The instances are deleted and recreated using the current instance template for the managed instance group. This operation is marked as DONE when the action is scheduled even if the instances have not yet been recreated. You must separately verify the status of the recreating action with the listmanagedinstances method.

If the group is part of a backend service that has enabled connection draining, it can take up to 60 seconds after the connection draining duration has elapsed before the VM instance is removed or deleted.

You can specify a maximum of 1000 instances with this method per request.
resize
Resizes the managed instance group. If you increase the size, the group creates new instances using the current instance template. If you decrease the size, the group deletes instances. The resize operation is marked DONE when the resize actions are scheduled even if the group has not yet added or deleted any instances. You must separately verify the status of the creating or deleting actions with the listmanagedinstances method.

If the group is part of a backend service that has enabled connection draining, it can take up to 60 seconds after the connection draining duration has elapsed before the VM instance is removed or deleted.
resizeAdvanced
Resizes the managed instance group with advanced configuration options like disabling creation retries. This is an extended version of the resize method.

If you increase the size of the instance group, the group creates new instances using the current instance template. If you decrease the size, the group deletes instances. The resize operation is marked DONE when the resize actions are scheduled even if the group has not yet added or deleted any instances. You must separately verify the status of the creating, creatingWithoutRetries, or deleting actions with the get or listmanagedinstances method.

If the group is part of a backend service that has enabled connection draining, it can take up to 60 seconds after the connection draining duration has elapsed before the VM instance is removed or deleted.
setAutoHealingPolicies
Modifies the autohealing policies.
setInstanceTemplate
Specifies the instance template to use when creating new instances in this group. The templates for existing instances in the group do not change unless you recreate them.
setTargetPools
Modifies the target pools to which all instances in this managed instance group are assigned. The target pools automatically apply to all of the instances in the managed instance group. This operation is marked DONE when you make the request even if the instances have not yet been added to their target pools. The change might take some time to apply to all of the instances in the group depending on the size of the group.
testIamPermissions
Returns permissions that a caller has on the specified resource.
update
Updates a managed instance group using the information that you specify in the request. This operation is marked as DONE when the group is updated even if the instances in the group have not yet been updated. You must separately verify the status of the individual instances with the listManagedInstances method.

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