Is there a way to automatically terminate unhealthy EC2 instances from ELB?

Question

Is there any way to have either ELB or an EC2 auto-scaling group terminate (or reboot) unhealthy instances from ELB?

There are some specific database failure conditions in our front end which makes it turn unhealthy, so the ELB will stop routing traffic to it. That instance is also part of an auto-scaling group, which scales on the group's CPU Load. So, what ends up happening is that the instance no longer gets traffic from ELB, so it has no CPU load, and skews the group's CPU load, thus screwing up the scaling conditions.

Is there an "easy" way to somehow configure ELB or an autoscaling group to automatically terminate unhealthy instances from the group without actually having to write code to do the polling and terminating via the EC2 API?

http://stackoverflow.com/questions/10541363/self-terminating-aws-ec2-instance — bobby reddy, Jan 29 '13 at 19:59

score 12 · Accepted Answer · answered Jan 29 '13 at 20:01

12

If you set the autoscaling group's health check type to ELB then it will automatically retire any instances that fail the ELB health checks (ie doesn't respond in a timely manner to the URL configured)

As long as the configured health check properly reports than an instance is bad (which sounds like it is the case since you say ELB is marking the instance as unhealthy) this should work

answered Jan 29 '13 at 20:01

Frederick Cheung

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Will changing the health check to ELB mean EC2 metrics like CPU Utilization will be ignored? – Varda Elentári Jan 06 '17 at 19:17
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@VardaElentári shouldn't make any difference. – Frederick Cheung Jan 06 '17 at 19:18

Is there a way to automatically terminate unhealthy EC2 instances from ELB?

1 Answers1