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Phuong Nguyen
Asked: 2014-08-26 22:06:15 +0800 CST

Monit config restart program

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I have monit configuration like this:

check process unicorn
with pidfile /tmp/pids/unicorn.0.pid
start program = "/etc/init.d/unicorn start"
stop program = "/etc/init.d/unicorn stop"
restart program = "/etc/init.d/unicorn reload"
if mem is greater than 250.0 MB for 2 cycles then restart
if cpu is greater than 22% for 3 cycles then alert
if cpu is greater than 25% for 2 cycles then restart

But look like whenever monit tries to reload the app (e.g due to memory > 250MB), it issues a stop and then a start, rather than use the restart program. Is there a way to tell monit to run the restart instead? Since issue a stop and a start cause the website to goes down for some moment.

monit

2 Answers

  1. I'm seeing the same problem as you reported. I don't know why the 'restart program' is not used to do a restart. However, the workaround I'm using is this:

    check process unicorn
with pidfile /tmp/pids/unicorn.0.pid
start program = "/etc/init.d/unicorn start"
stop program = "/etc/init.d/unicorn stop"
if mem is greater than 250.0 MB for 2 cycles then restart
if cpu is greater than 22% for 3 cycles then alert
if cpu is greater than 25% for 2 cycles then exec "/etc/init.d/unicorn reload"

    Note that I left the 'if mem' check so that it will do a stop/start. This is because I presume that the reload probably won't help if you have a memory leak thus a stop/start is likely necessary. But tweak as you see fit.

    Short of digging into the monit source code and fixing it (or installing a newer version and finding out if it is already fixed) this is probably your best option.

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  2. Which version of monit are you using ?

    you syntax for restart seems legit

    did you check the web interface to ensure configuration is parsed as attended ?

    documentation states

    RESTART restarts the service and send an alert. Restart is performed by calling the service's registered restart method or by first calling the stop method followed by the start method if restart is not set.

    The method Monit use for restart is to first execute the stop-program, then wait (up to 30s) for the process to stop and then execute the start-program and wait (30s) for it to start.

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