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I intend to reboot a running AWS instance which has been marked as unhealthy behind an ELB.

I have a setup where 2 instances are behind a Load Balancer and one of them contains lot of (>200 Gb) data in ephemeral store. The data is not important so I don't want to put it in S3 or EBS and pay for it but I don't want to lose it either.

Is there a way to tell load balancer to detect unhealthy instances and hard reboot them instead of terminating?

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If you don't want to lose your data, then it is important. – Eric Hammond Dec 28 '11 at 9:24
It is kind of data for which I don't need 99.99...% availability and yet I don't want to delete often. Ephemeral storage fits this kind of need. – Mridul Kashatria Dec 28 '11 at 9:48
Ephemeral storage may disappear at any moment outside of your control, such as when an instance fails. If you don't want to lose your data, put it somewhere persistent and not ephemeral. If you put important data on ephemeral storage, it should be easy to recreate from other sources. – Eric Hammond Dec 28 '11 at 11:09
  • Configure alarm depends on ELB metrics to inform you of UnhealthyChecks
  • You can ban terminating of the machine by enabling Termination Protection Enable/ Disable Termination Protection

  • You can save your AMI template and make sure that Autoscalling would open you a similar instance

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Using cloud watch, you can set custom action by creating a http endpoint to reboot your instance.You can write a http endpoint(simple servlet) to receive and initiate action as per your need.Clouw watch will send a notification to your endpoint once it detects that your instance is unhealthy.

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