Ubuntu – Can’t find httpd.pid to use for Monit apache2 monitoring

apache-2.2httpdmonitUbuntu

I'm new to Linux and I setup Ubuntu 12.04 on Digital Ocean.

I installed Monit and got it to monitor MySQL successfully with email alert.

I want to monitor Apache2 as well but cannot find any httpd.pid file needed to put in monitrc file.

I can start Apache2 with: /etc/init.d/apache2 start

I can stop Apache2 with: /etc/init.d/apache2 stop

I can restart Spache2 with: /etc/init.d/apache2 restart

What other way is there to monitor Apache2 in Monit without a httpd.pid file?

Best Answer

If you look in the init script it uses the value of $APACHE_PID_FILE which it reads from the file defined as $APACHE_ENVVARS which I think defaults to /etc/apache2/envvars

PIDFILE=$(. $APACHE_ENVVARS && echo $APACHE_PID_FILE)

In the envvars file PIDFILE is defined as

APACHE_PID_FILE=/var/run/apache2$SUFFIX.pid

Unless you are running multiple instances of apache2 $SUFFIX will likely be "" so the value of $APACHE_PID_FILE will be

/var/run/apache2.pid

but you should be able to run

echo $(. /etc/apache2/envvars && echo $APACHE_PID_FILE)

and get what your system thinks the value is.

Related Solutions

Linux – monit syntax error : “if 5 restarts within 5 cycles then alert”

It looks like support for this was added in monit 5.1
From the changelog at http://mmonit.com/monit/dist/CHANGES.txt :

Version 5.1

NEW FEATURES AND FUNCTIONS:

It is now possible to define any action for the restart timeout rule.
  Multiple restart timeout rules can also be defined. Example:
  if 3 restarts within 5 cycles then exec "/foo/bar"
  if 8 restarts within 10 cycles then unmonitor

I was trying to use the exact same syntax as you (for the exact same reason), and found it was working on one server but another. When I compared versions, I found one was 5.2.5 and the other was 4.10.1

So the answer it seems is to upgrade to at least 5.1

Monit is restarting apache2, should I fix the monit config, or the server config

In and of itself, using more than 200MB of RAM isn't necessarily an issue for your apache server. But I think that you just need to figure out what is acceptable for your setup.

If there's nothing else on that VPS, I think it's safe to allow apache more than 200M as an upper limit.

If you have the time and know-how, you can certainly find ways to bring that number down, but it may be more efficient for you to just bump up your monit threshold and not have it keep restarting. For all you know, it might stabilise at 201MB of usage, right (unlikely, but you see my point).

If I were in your shoes, I wouldn't consider it acceptable to have apache restarted every once in a while... stability is desirable... more so than an arbitrary amount of free RAM available on the server.

Best Answer

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Linux – monit syntax error : “if 5 restarts within 5 cycles then alert”

Monit is restarting apache2, should I fix the monit config, or the server config

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