Restarting services when they stop

[wiggst3r]

Hi

 

I'm running a Ubuntu webserver, which has several services running.

 

As the server is quite well used and has several sites hosted on it, I was wondering If anyone could help me with some code/script that will restart any service that goes down or stops.

 

I'm looking to restart the following, If they ever stop:

 

Apache

Mongrel

MySQL

Cron

Postfix

 

I'm sure there could be an init script that could be run and will restart any of these services If they ever stop.

 

Thanks

[Daniel0]

You could write a script that checks if it's running, and if not then start it. Then add a cron entry to run it at a certain interval.

 

So, on my Gentoo VPS, if I might do something like this:

degeberg ~ # /etc/init.d/apache2 status
* status:  started

 

So that tells me that Apache is running. If it hadn't returned that then I could execute /etc/init.d/apache2 start to start Apache. Do that for all of your services, make a script out of it and use cron to routinely run it. This can of course not be used to check if your cron daemon is down, but I don't think you can guard against that without having an external server check that.

[steviewdr]

See monit.

http://www.debianadmin.com/monitoring-debian-servers-using-monit.html

 

Its probably on apt for ubuntu also.

 

The problem I foresee is, that if your server OOM's (runs out of memory) then the monit service itself will have its memory squeezed and could stop as wekk.

 

-steve

[Daniel0]

Yeah that was essentially the problem in my post as well. If the monitor fails, who monitors the monitor?

[steviewdr]

Well I use Xen, a lot. So much so, I have all my services broken out amongst 3 vm's. Dom0 (running solid and very capable on 128mb of ram) can then monitor to see if a domU has OOM'd etc. destroy the vm and create a new vm instance.

 

Of course there is a lot of setting up in that.

 

-steve