Debugging monit

Question

I find debugging monit to be a major pain. Monit\'s shell environment basically has nothing in it (no paths or other environment variables). Also, there are no log file that

Answer 1

Be sure to always double check your conf and monitor your processes by hand before letting monit handle everything. systat(1), top(1) and ps(1) are your friends to figure out resource usage and limits. Knowing the process you monitor is essential too.

Regarding the start and stop scripts i use a wrapper script to redirect output and inspect environment and other variables. Something like this :

$ cat monit-wrapper.sh

#!/bin/sh
{
  echo "MONIT-WRAPPER date"
  date
  echo "MONIT-WRAPPER env"
  env
  echo "MONIT-WRAPPER $@"
  $@
  R=$?
  echo "MONIT-WRAPPER exit code $R"
} >/tmp/monit.log 2>&1

Then in monit :

start program = "/home/billitch/bin/monit-wrapper.sh my-real-start-script and args"
stop program = "/home/billitch/bin/monit-wrapper.sh my-real-stop-script and args"

You still have to figure out what infos you want in the wrapper, like process infos, id, system resources limits, etc.