Monit can't restart nginx

Question

I've got monit up and running on an Ubuntu 12.04 server, to monitor nginx, but I can't get it to successfully start nginx up again. My setup is thus: the monit config file is:

-rwx------ 1 root root 10329 2015-07-31 09:39 /etc/monit/monitrc

and the content (non commented) of the monitrc file is

set daemon  60
set logfile /var/www/apps/myapp/log/monit.log

set httpd port 2812
  use address mysite.com       
  allow username:password 'password'

check system mysite.com
  if loadavg (1min) > 4 then alert
  if loadavg (5min) > 2 then alert
  if memory usage > 75% then alert
  if cpu usage (user) > 70% then alert
  if cpu usage (system) > 30% then alert
  if cpu usage (wait) > 20% then alert

check process nginx with pidfile /opt/nginx/logs/nginx.pid
  start program = "/etc/init.d/nginx restart; touch /var/www/apps/myapp/tmp/restart.txt"
  stop program = "/etc/init.d/nginx stop"

I'm starting monit with sudo monit.

If I kill nginx and then wait for monit to try to start it, I see this in the log file:

[UTC Jul 31 09:39:26] info     : Reinitializing monit daemon
[UTC Jul 31 09:39:26] info     : Starting monit HTTP server at [mysite.com:2812]
[UTC Jul 31 09:39:26] info     : monit HTTP server started
[UTC Jul 31 09:39:26] info     : 'myhost.mydomain.tld' Monit reloaded
[UTC Jul 31 09:40:26] error    : 'nginx' process is not running
[UTC Jul 31 09:40:26] info     : 'nginx' trying to restart
[UTC Jul 31 09:40:26] info     : 'nginx' start: /etc/init.d/nginx
[UTC Jul 31 09:40:56] error    : 'nginx' failed to start

When I run the nginx restart command myself in the terminal then it works fine:

sudo /etc/init.d/nginx restart; touch /var/www/apps/myapp/tmp/restart.txt

this restarts it fine (the touch command is to reload a ruby app which is running under Passenger - touching the restart file triggers the restart of the app.)

Taking the touch command out of the line in the monit config doesn't make any difference. When I try to restart nginx via monit's web interface, that also fails.

I think that if I could somehow get the STDERR and STDOUT streams into the log file as well, when monit tries to start nginx, that would help at least.

Any suggestions?

monit relys on PID file `/opt/nginx/logs/nginx.pid` to know whether or not the process to be watched (`nginx`) is alive and running. By running `/etc/init.d/nginx restart` does `nginx` certainly create `nginx.pid` with its PID in the content? — yaegashi, Jul 31 '15 at 10:17
yes - after starting nginx manually, i have `-r-------- 1 root root 5 2015-07-31 10:18 /opt/nginx/logs/nginx.pid` — Max Williams, Jul 31 '15 at 10:24

score 1 · Accepted Answer · answered Jul 31 '15 at 10:34

monit doesn't accept shell scripts with start program/stop program. You need to write like this:

check process nginx with pidfile /opt/nginx/logs/nginx.pid
  start program = "/bin/sh -c '/etc/init.d/nginx restart; touch /var/www/apps/myapp/tmp/restart.txt'"
  stop program = "/etc/init.d/nginx stop"

Monit can't restart nginx

1 Answers1