Fair Proxy Balancer
rtibmx at yahoo.com
Tue May 6 22:30:47 MSD 2008
>Isn't the point of using Amazon EC2 exactly that you get guarantee
>that your virtual machine will not be affected by normal problems
>related to hosting it on a single machine. I mean they say that they
>have a copy of your virtual machine on more than on server on maybe
>more than one location. I may be wrong here but from what I have read,
>you should not worry about your instance shutting down or slowing down
>drastically because what happens if I only have one instance and I
>reply on that?
Instances on EC2 can and sometimes do go down. I have not had it happen to me yet. However if you look at the forums there you will see occasional posts like "i'm having network problems" or "i'm having slow response" etc and sometimes the reply from Amazon is that something was not right on the physical box the instance was running on and they have rebooted that box and they should now be fine.
To make our solution as resilient as possible we will run nginx on multiple instances in multiple availability zones, and these will connect to other multiple upstream instances in multiple availability zones We are expecting that from time to time one or more instances will go down or suffer from performance problems not related to our app/coding but rather the ec2 infrastructure. After all technically ec2 is still considered beta.
So with this in mind we have very big needs for monitoring upstream servers closely (and hopefully Francois is on track for this with his great ideas about enhancing nginx moniroting) and things like 'fair' which take into account the response times of the upstreams would be VERY helpful. This way if an upstream is suffering (but not meeting the failure requirements of nginx to take the upstream out of rotation) than 'fair' can at least keep those requests to a minimum. With the right enhancements to 'fair' that is.
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