You should read this paper:
http://www.techmasala.com/2009/04/06/dynamically-scale-web-applications-in-amazon-ec2/

2009/9/8 Nuno Magalhães <nunomagalhaes@eu.ipp.pt>:
>> Yeah for sure wget call would do it, but communicate the result from wget to Nginx in order to drop the misbehaving worker out?
>
> I don't know about one single worker, but you can HUP nginx, it'll
> create new workers. See [1]. Of course if the bad worker is just
> frozen or dead, i guess you'd have to kill it first, then HUP nginx
> main process.
>
> I think nginx will wait until workers are free before replacing them,
> hence the need to maybe kill the lazy worker.
>
> HTH
>
> [1] http://wiki.nginx.org/NginxCommandLine#Controlling_Nginx_Via_the_Signals
>
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