Monit will not stop script with kill command
I am using monit to monitor several process. These process include passenger instances and a daemon I wrote to generate pidfiles for the passenger instance. Monit will start these process no problem. It will not stop them. The following is the Monit config for the daemon:
check process passenger_monitor with pidfile <%= passenger_monitor_pid %>
group <%= application %>
start program = "/bin/su - rails_apps -c 'source /home/rails_apps/.rvm/scripts/rvm; /home/rails_apps/passenger_monitor.rb'"
stop program = "/bin/kill `/bin/cat <%= passenger_monitor_pid %>`"
It is a erb template that is generated via capistrano. If I run the stop command via a terminal as root with a minimal environment then it works, but when I request that Monit stops the process i get the following error:
[ADT Sep 17 10:38:31] error : 'passenger_monitor' failed to stop
I have tried everything I can think of. I cannot find or generate any logs of the output of the stop command.
Answer
I have the same issue when trying to stop a service using
stop program = "/bin/kill `/bin/cat /var/run/pusher.pid`"
You can turn on the -Iv flag to see the debug output:
monit -Iv
Or you can manually validate while monit is running in the background:
monit validate
They both show
'api-pusher-service' stop: /bin/kill
kill: can't find process "`/bin/cat"
kill: can't find process "/var/run/pusher.pid`"
This fixes the problem for me
stop program = "/bin/bash -c '/bin/kill `/bin/cat /var/run/pusher.pid`'"