Aws auto scaling group terminated one ec2 instance with Instance status check fails

Question

Auto scaling group in Aws terminated one ec2 instance with Instance status check fails and re launched another instance which is running fine.. Is there any way to check which causes my ASG to terminate machine with instance status check failure

Answer 1

You can grab the instance-id from the Activity History tab under your Auto Scaling Group, then use CloudWatch Log Insights to query any logs you may be pushing up into CloudWatch e.g.

fields @timestamp, @message
| filter @logStream = 'i-your-instance-id'
| sort @timestamp desc
| limit 200

If it happens regularly you may want to try detaching the instance from your ASG or alternatively suspending the HealthCheck process so you can log in to the instance and troubleshoot in more detail.

For additional troubleshooting steps refer to the AWS Docs for troubleshooting instances in Linux and Windows.