AWS: Move Auto Scaling Group Into Standby
Availability
This workflow action is available only to customers on PagerDuty Operations Cloud plans. See Operations Cloud pricing for more information.
Description
Move one or more EC2 instances in an Auto Scaling Group (ASG) into Standby. Instances in Standby are detached from load balancers and do not receive traffic; the ASG can launch replacement instances if desired capacity is maintained. You can choose whether to decrement desired capacity by the number of instances moved to standby. This action is useful for:
- Rotating instances out of an ASG during incident response (e.g., move to standby, wait for replacement, then terminate)
- Taking instances out of service for maintenance or troubleshooting without terminating them
- Building runbooks that combine with Set Instance Protection, Describe Auto Scaling Instances, and Terminate Instance in Auto Scaling Group
- Letting the ASG launch replacement instances before terminating the old one when Should Decrement Desired Capacity is set to false
Instructions
- If you have not done so, follow the instructions to Create an Incident Workflow.
- When the instructions prompt you to add actions, select this action.
- Enter the following Inputs and click Save.
- Continue following instructions to Publish the Workflow.
- When the action runs, you will see the Outputs listed below.
Inputs
Field References
Fields with the {+} icon accept Field References, which can be useful for referencing incident data or outputs created in prior workflow steps. To add Field References, click {+}, or enter
{{, and select relevant fields. Refer to the Field References article for more information.
| Name | Description |
|---|---|
| Integration | Select a Workflow Integration or click New AWS Connection to establish a new one. |
| Auto Scaling Group Name | The name of the Auto Scaling Group that contains the instances. |
| Instance IDs | One or more EC2 instance IDs to move to Standby (comma-separated). Can be from a prior step (e.g., Describe Auto Scaling Instances) or from incident custom details. |
| AWS Region | The AWS region where the ASG is located. If left blank, the action uses us-east-1 as the default. |
| Should Decrement Desired Capacity | Whether to reduce the ASG's desired capacity by the number of instances moved to standby. Set to false (default) to keep capacity so the ASG launches replacements; set to true to shrink the group. |
Outputs
| Name | Description |
|---|---|
| Activities | JSON array of Auto Scaling activity records returned by the API for the Enter Standby operation. |
| Placed In Standby | Array of instance IDs that were successfully placed in Standby. |
| Result | Whether the action succeeded: Success or Failed. |
| Result Summary | Brief description of what the action did or if it failed. |
| Error | Error message, if the action failed. |
Tips
- Instance Rotation: For instance-rotation runbooks, use Should Decrement Desired Capacity = false so the ASG launches a replacement before you terminate the instance in a later step.
- Chaining Actions: Use the Auto Scaling Group Name and Instance IDs from Auto Scaling: Describe Auto Scaling Instances so the workflow works when the incident only provides an instance ID.
Updated about 2 hours ago