AWS::AutoScaling::ScheduledAction

The AWS::AutoScaling::ScheduledAction resource specifies an Amazon EC2 Auto Scaling scheduled action so that the Auto Scaling group can change the number of instances available for your application in response to predictable load changes.

When you update a stack with an Auto Scaling group and scheduled action, CloudFormation always sets the min size, max size, and desired capacity properties of your group to the values that are defined in the AWS::AutoScaling::AutoScalingGroup section of your template. However, you might not want CloudFormation to do that when you have a scheduled action in effect. You can use an UpdatePolicy attribute to prevent CloudFormation from changing the min size, max size, or desired capacity property values during a stack update unless you modified the individual values in your template. If you have rolling updates enabled, before you can update the Auto Scaling group, you must suspend scheduled actions by specifying an UpdatePolicy attribute for the Auto Scaling group. You can find a sample update policy for rolling updates in Configure Amazon EC2 Auto Scaling resources.

For more information, see Scheduled scaling and Suspending and resuming scaling processes in the Amazon EC2 Auto Scaling User Guide.

Syntax

To declare this entity in your Amazon CloudFormation template, use the following syntax:

{
  "Type" : "AWS::AutoScaling::ScheduledAction",
  "Properties" : {
      "AutoScalingGroupName" : String,
      "DesiredCapacity" : Integer,
      "EndTime" : String,
      "MaxSize" : Integer,
      "MinSize" : Integer,
      "Recurrence" : String,
      "StartTime" : String,
      "TimeZone" : String
    }
}

Type: AWS::AutoScaling::ScheduledAction
Properties:
  AutoScalingGroupName: String
  DesiredCapacity: Integer
  EndTime: String
  MaxSize: Integer
  MinSize: Integer
  Recurrence: String
  StartTime: String
  TimeZone: String

Properties

Return values

Ref

When you pass the logical ID of this resource to the intrinsic Ref function, Ref returns the resource name. For example: mystack-myscheduledaction-NT5EUXTNTXXD.

For more information about using the Ref function, see Ref.

Fn::GetAtt

The Fn::GetAtt intrinsic function returns a value for a specified attribute of this type. The following are the available attributes and sample return values.

For more information about using the Fn::GetAtt intrinsic function, see Fn::GetAtt.

Examples

The following examples schedule scaling actions for an Auto Scaling group.

Scheduled actions that run on a recurring schedule

The following template snippet includes two scheduled actions that scale the number of instances in an Auto Scaling group. The ScheduledActionOut action starts at 7 AM every day and sets the Auto Scaling group to a minimum of five Amazon EC2 instances with a maximum of 10. The ScheduledActionIn action starts at 7 PM every day and sets the Auto Scaling group to a minimum and maximum of one Amazon EC2 instance. The time zone is not provided. As a result, these scheduled actions will recur in UTC time.

{
  "Resources":{
    "ScheduledActionOut":{
      "Type":"AWS::AutoScaling::ScheduledAction",
      "Properties":{
        "AutoScalingGroupName":{
          "Ref":"myASG"
        },
        "MaxSize":"10",
        "MinSize":"5",
        "Recurrence":"0 7 * * *"
      }
    },
    "ScheduledActionIn":{
      "Type":"AWS::AutoScaling::ScheduledAction",
      "Properties":{
        "AutoScalingGroupName":{
          "Ref":"myASG"
        },
        "MaxSize":"1",
        "MinSize":"1",
        "Recurrence":"0 19 * * *"
      }
    }
  }
}

---
Resources:
  ScheduledActionOut: 
    Type: AWS::AutoScaling::ScheduledAction
    Properties:
      AutoScalingGroupName: !Ref myASG
      MaxSize: '10'
      MinSize: '5'
      Recurrence: "0 7 * * *"
  ScheduledActionIn: 
    Type: AWS::AutoScaling::ScheduledAction
    Properties:
      AutoScalingGroupName: !Ref myASG
      MaxSize: '1'
      MinSize: '1'
      Recurrence: "0 19 * * *"

Scheduled scaling action that occurs only once

The following template snippet includes a one-time scheduled action. At the date and time specified for StartTime (4:00 PM UTC on March 31, 2021), if the group currently has more than 1 instance, it scales in to 1 instance. If the group currently has no instances, it scales out to 1 instance.

{
  "Resources":{
    "OneTimeScheduledAction":{
      "Type":"AWS::AutoScaling::ScheduledAction",
      "Properties":{
        "AutoScalingGroupName":{
          "Ref":"myASG"
        },
        "DesiredCapacity":"1",
        "StartTime":"2021-03-31T16:00:00Z"
      }
    }
  }
}

---
Resources:
  OneTimeScheduledAction:
    Type: AWS::AutoScaling::ScheduledAction
    Properties:
      AutoScalingGroupName: !Ref myASG
      DesiredCapacity: '1'
      StartTime: '2021-03-31T16:00:00Z'

See also