Re: processes/threads monitor

[Willy Tarreau <w@1wt.eu>]

On Sat, Jan 31, 2009 at 10:57:36PM +0100, Angelo Borsotti wrote:
(...)
> A much more efficient solution would be for the process monitor to be
> allowed to wait
> for the termination of any processes/threads belonging to a specified list.
> Note that this would mean waiting for one among several events to occur.
> 
> Are there any solution to this?

This is called a launcher or wrapper. Your process just has to fork/exec
the process to monitor, and it receives a sigchild when that one dies.
One well-known process does that all the time, it's called init :-)

But this does not save you from checking that your processes are properly
working. A process which just dies is the trivial case. Most unhandled
errors are from stuck processes, which need to be killed and respawned.
So if you have to check that a process is working correctly and you can
kill it, it's often easy to restart it, and you don't need your wrapper.

You're back to the script you found inefficient ;-)

Cheers,
Willy