Linux – Simple way of restarting crashed processes

linuxmonitmonitoringvarnishweb-server

I need to monitor several processes running on my webserver. For some reason, varnish currently crashes once every day or two. I'm using monit to supposedly restart varnish automatically, but it doesn't work. Here's my monit.conf entry for Varnish.

check process varnish with pidfile /var/run/varnish.pid
    start program = "/etc/init.d/varnish start" with timeout 60 seconds
    stop program = "/etc/init.d/varnish stop"
    if failed host <my server ip> port 80 protocol http
        and request "/blank.html" then restart
    if 3 restarts within 5 cycles then timeout
    group server

The log file shows that after varnish stops running, the attempted restarts afterwards all fail. Then eventually monit stops monitoring varnish.

Anyone have suggestions for how I can fix this? Or better yet, can you suggest other simple ways of automatically monitoring and restarting crashed processes? Thanks!

Best Answer

I'd look in to daemontools (http://cr.yp.to/daemontools.html).

Supervise was built for exactly this purpose -- to start processes and watch them, restarting them immediately if they ever terminate.

You could still use monit if you need to do anything more complicated than a simple "is it still running" check, and if the process needs to be restarted, then do that through supervise.

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