Ensure that your AWS Auto Scaling Groups (ASGs) launch configuration is referencing an active Amazon Machine Image (AMI) in order to maintain the auto-scaling process healthy
When your ASGs fail to launch new EC2 instances due to invalid (removed) AMIs, the scaling mechanism is unable to add compute resources to handle the load and this will cause a significant negative impact on your application performance.
To identify any unhealthy Auto Scaling Groups (i.e. ASGs that reference invalid AMIs), perform the following actions:
To fix any unhealthy AWS Auto Scaling Groups by replacing their invalid launch configuration with a valid one, perform the following: