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Currently we have on c1.medium webnode and an Amazon RDS sql server. The problem we face is that every now and then the webnode fails and the site goes down. I am considering mitigating this risk by running two or three webnodes behind an ELB. However, the cost of doing this is discouraging, as we have already purchased reserved instances for our current set up.

My questions are:

  • How does ELB distribute traffic amongst the nodes behind it? By response time? By location?
  • Can I get AWS to restart dead nodes automatically? Where does the code that does this run? On existing healthy web nodes?
  • Will I need to set up something like GlusterFS for this configuration?
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Did setup health checks for your balancer? Once you setup it up you can always check for the instances health by:

elb-describe-instance-health mybalancer --headers --show-long

Can I get AWS to restart dead nodes automatically?

Hmm.. My idea is, you can have a cron job that checks your ELB for not responding instance and possible do restart.

Why you need glusterfs? :)

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GlusterFS would be to share the app's files across several EC2 instances – chrism2671 Dec 11 '10 at 11:54
hmm.. I see. Currently, I'm still using NFS to share files across several instances. And backup EBS regularly. Though currently testing moosefs. – rquillo Dec 12 '10 at 1:53

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