Suspend and resume scaling for Application Auto Scaling - Application Auto Scaling
Scaling activitiesSuspend and resume scaling activities
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Suspend and resume scaling for Application Auto Scaling

This topic explains how to suspend and then resume one or more of the scaling activities for the scalable targets in your application. The suspend-resume feature is used to temporarily pause scaling activities triggered by your scaling policies and scheduled actions. This can be useful, for example, when you don't want automatic scaling to potentially interfere while you are making a change or investigating a configuration issue. Your scaling policies and scheduled actions can be retained, and when you are ready, scaling activities can be resumed.

In the example CLI commands that follow, you pass the JSON-formatted parameters in a config.json file. You can also pass these parameters on the command line by using quotation marks to enclose the JSON data structure. For more information, see Using quotation marks with strings in the Amazon CLI in the Amazon Command Line Interface User Guide.

Note

For instructions for suspending scale-out processes while Amazon ECS deployments are in progress, see the following documentation:

Service auto scaling and deployments in the Amazon Elastic Container Service Developer Guide

Scaling activities

Application Auto Scaling supports putting the following scaling activities in a suspended state:

  • All scale-in activities that are triggered by a scaling policy.

  • All scale-out activities that are triggered by a scaling policy.

  • All scaling activities that involve scheduled actions.

The following descriptions explain what happens when individual scaling activities are suspended. Each one can be suspended and resumed independently. Depending on the reason for suspending a scaling activity, you might need to suspend multiple scaling activities together.

DynamicScalingInSuspended

  • Application Auto Scaling does not remove capacity when a target tracking scaling policy or a step scaling policy is triggered. This allows you to temporarily disable scale-in activities associated with scaling policies without deleting the scaling policies or their associated CloudWatch alarms. When you resume scale in, Application Auto Scaling evaluates policies with alarm thresholds that are currently in breach.

DynamicScalingOutSuspended

  • Application Auto Scaling does not add capacity when a target tracking scaling policy or a step scaling policy is triggered. This allows you to temporarily disable scale-out activities associated with scaling policies without deleting the scaling policies or their associated CloudWatch alarms. When you resume scale out, Application Auto Scaling evaluates policies with alarm thresholds that are currently in breach.

ScheduledScalingSuspended

  • Application Auto Scaling does not initiate the scaling actions that are scheduled to run during the suspension period. When you resume scheduled scaling, Application Auto Scaling only evaluates scheduled actions whose execution time has not yet passed.

Suspend and resume scaling activities

You can suspend and resume individual scaling activities or all scaling activities for your Application Auto Scaling scalable target.

Note

For brevity, these examples illustrate how to suspend and resume scaling for a DynamoDB table. To specify a different scalable target, specify its namespace in --service-namespace, its scalable dimension in --scalable-dimension, and its resource ID in --resource-id. For more information and examples for each service, see the topics in Amazon services that you can use with Application Auto Scaling.

To suspend a scaling activity

Open a command-line window and use the register-scalable-target command with the --suspended-state option as follows.

Linux, macOS, or Unix

aws application-autoscaling register-scalable-target --service-namespace dynamodb \
  --scalable-dimension dynamodb:table:ReadCapacityUnits --resource-id table/my-table \
  --suspended-state file://config.json

Windows

aws application-autoscaling register-scalable-target --service-namespace dynamodb --scalable-dimension dynamodb:table:ReadCapacityUnits --resource-id table/my-table --suspended-state file://config.json

If successful, this command returns the ARN of the scalable target.

{
    "ScalableTargetARN": "arn:aws-cn:application-autoscaling:region:account-id:scalable-target/1234abcd56ab78cd901ef1234567890ab123"
}

To only suspend scale-in activities that are triggered by a scaling policy, specify the following in config.json.

{
    "DynamicScalingInSuspended":true
}

To only suspend scale-out activities that are triggered by a scaling policy, specify the following in config.json.

{
    "DynamicScalingOutSuspended":true
}

To only suspend scaling activities that involve scheduled actions, specify the following in config.json.

{
    "ScheduledScalingSuspended":true
}
To suspend all scaling activities

Use the register-scalable-target command with the --suspended-state option as follows.

Linux, macOS, or Unix

aws application-autoscaling register-scalable-target --service-namespace dynamodb \
  --scalable-dimension dynamodb:table:ReadCapacityUnits --resource-id table/my-table \
  --suspended-state file://config.json

Windows

aws application-autoscaling register-scalable-target --service-namespace dynamodb --scalable-dimension dynamodb:table:ReadCapacityUnits --resource-id table/my-table --suspended-state file://config.json

This example assumes that the file config.json contains the following JSON-formatted parameters. 

{
    "DynamicScalingInSuspended":true,
    "DynamicScalingOutSuspended":true,
    "ScheduledScalingSuspended":true
}

If successful, this command returns the ARN of the scalable target.

{
    "ScalableTargetARN": "arn:aws-cn:application-autoscaling:region:account-id:scalable-target/1234abcd56ab78cd901ef1234567890ab123"
}

View suspended scaling activities

Use the describe-scalable-targets command to determine which scaling activities are in a suspended state for a scalable target.

Linux, macOS, or Unix

aws application-autoscaling describe-scalable-targets --service-namespace dynamodb \
  --scalable-dimension dynamodb:table:ReadCapacityUnits --resource-id table/my-table

Windows

aws application-autoscaling describe-scalable-targets --service-namespace dynamodb --scalable-dimension dynamodb:table:ReadCapacityUnits --resource-id table/my-table

The following is example output.

{
    "ScalableTargets": [
        {
            "ServiceNamespace": "dynamodb",
            "ScalableDimension": "dynamodb:table:ReadCapacityUnits",
            "ResourceId": "table/my-table",
            "MinCapacity": 1,
            "MaxCapacity": 20,
            "SuspendedState": {
                "DynamicScalingOutSuspended": true,
                "DynamicScalingInSuspended": true,
                "ScheduledScalingSuspended": true
            },
            "CreationTime": 1558125758.957,
            "RoleARN": "arn:aws-cn:iam::123456789012:role/aws-service-role/dynamodb.application-autoscaling.amazonaws.com/AWSServiceRoleForApplicationAutoScaling_DynamoDBTable"
        }
    ]
}

Resume scaling activities

When you are ready to resume the scaling activity, you can resume it using the register-scalable-target command.

The following example command resumes all scaling activities for the specified scalable target.

Linux, macOS, or Unix

aws application-autoscaling register-scalable-target --service-namespace dynamodb \
  --scalable-dimension dynamodb:table:ReadCapacityUnits --resource-id table/my-table \
  --suspended-state file://config.json

Windows

aws application-autoscaling register-scalable-target --service-namespace dynamodb --scalable-dimension dynamodb:table:ReadCapacityUnits --resource-id table/my-table --suspended-state file://config.json

This example assumes that the file config.json contains the following JSON-formatted parameters. 

{
    "DynamicScalingInSuspended":false,
    "DynamicScalingOutSuspended":false,
    "ScheduledScalingSuspended":false
}

If successful, this command returns the ARN of the scalable target.

{
    "ScalableTargetARN": "arn:aws-cn:application-autoscaling:region:account-id:scalable-target/1234abcd56ab78cd901ef1234567890ab123"
}