AWS: Retrieve Capacity, Health, and Instance of ASG

Returns desired capacity, minimum and maximum size, and per-instance health and lifecycle state for one or more Auto Scaling Groups.

Availability

See the Incident Workflow Actions Overview table for the plans this workflow is available on.

Description

Premium. This action is a Premium Workflow Action, billed separately from your PagerDuty plan. In the workflow action picker, this action appears as Auto Scaling: Describe Auto Scaling Groups.

Retrieve capacity, health, and instance membership for one or more Auto Scaling Groups (ASGs). The action returns desired capacity, min and max size, and a list of instances in each group with their lifecycle state, health status, and protection settings. This action is useful for:

Checking current ASG capacity before scaling up or adjusting max size during instance rotation
Building conditional logic (e.g., only bump max size when desired equals max) in multi-step runbooks
Gathering diagnostic information about which instances are in service, in standby, or unhealthy
Chaining with Update Auto Scaling Group or other Auto Scaling actions in a single workflow

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 Names	One or more Auto Scaling Group names to describe (comma-separated). You can reference the ASG name from a prior step (e.g., from Describe Auto Scaling Instances).
AWS Region	The AWS region where the Auto Scaling Groups are located. If left blank, the action uses `us-east-1` as the default.

Outputs

Name	Description
Groups	JSON array of ASG details. Each group includes: asgName, desiredCapacity, minSize, maxSize, instances (array with instanceId, lifecycleState, healthStatus, protectedFromScaleIn, availabilityZone, launchTemplate, launchConfigurationName), targetGroupARNs, loadBalancerNames, terminationPolicies.
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

Chaining Actions: Use the output from Auto Scaling: Describe Auto Scaling Instances (e.g., instances[0].asgName) as the Auto Scaling Group Names input when building a rotate-or-scale workflow.
Conditional Logic: Reference Groups in a subsequent Logic step (e.g., groups[0].desiredCapacity, groups[0].maxSize) to implement conditional logic such as bumping max size only when at capacity.