How do I resolve the "Group did not stabilize" error that I receive when I update my Auto Scaling group through a CloudFormation stack?

Short description

After you invoke an Auto Scaling group update, CloudFormation confirms that the MinSize, MaxSize, and DesiredCapacity values are met. CloudFormation also verifies that the current capacity values are the same as the CloudFormation template values. Any difference in values might cause an update to fail and invoke a rollback.

The following reasons can cause the Group did not stabilize error to occur:

• An Auto Scaling group fails to reach the DesiredCapacity within 1 hour, and the stack update fails.
• An Auto Scaling group fails to stabilize when a RollingUpdate is in progress.

Resolution

To resolve the Group did not stabilize error, take the following actions:

• Specify the minimum percentage of the instances that must be in service in the Auto Scaling group when CloudFormation updates instances. If you expect the Auto scaling group not to meet capacity, then update the MinActiveInstancesPercent property of the AutoScalingRollingUpdate policy.
• Use the SuspendProcesses property to suspend Auto Scaling processes during a rolling update.

For general launch failures that occur when you use an Auto Scaling group, check the Auto Scaling group's Activity history.

Launch failures might occur for the following reasons:

• The auto scaling fails to launch instances because of lifecycle hooks with the ABANDON action.
• There's InsufficientInstanceCapacity in the Availability Zone.
• The launch fails because of encrypted Amazon Elastic Block Store (Amazon EBS) volumes.
• Some processes are suspended in the Auto Scaling group.
• You have insufficient AWS Identity and Access Management (IAM) permissions.