Today I wanted to setup monit behind Apache proxy on my webserver, which runs ISPConfig (https://www.ispconfig.org/) under Debian. Monit is a OpenSource monitoring tool for Linux (see https://mmonit.com/monit/).

Requirements

I had the following requirements on the solution:

• monit should only be accessible from the server itself (localhost)
• monit should run under a special SSL-secured URL (not IP:PORT as in default)
• monit should run password protected

set httpd port 2812 and
use address 127.0.0.1 # bind to loopback only
allow localhost       # allow only localhost to connect to the server and
allow ask:sheldon     # require user 'ask' and password 'sheldon'

Software Versions

• Debian 3.16.39-1 (2016-12-30) x86_64 GNU/Linux
• ISPConfig 1.3.2
• Apache 2.4.10 (Debian)
• Monit version 5.20.0

Steps to setup monit behind Apache proxy

1. First I had to login as root. But sudo-ing with a sudoers user should work as well.
2. Install monit:

   $> apt-get install monit
   $> service monit start

3. Add a new config file under /etc/monit/conf.d/ask-sheldon.cfg with the following content:

   set httpd port 2812 and
   use address 127.0.0.1 # bind to loopback only
   allow localhost       # allow only localhost to connect to the server and
   allow ask:sheldon     # require user 'ask' and password 'sheldon'

4. Setup a subdomain monitoring.ask-sheldon.com as a new website (sites tab in ISPConfig) with Let’s Encrypt (https://letsencrypt.org/) as SSL-maintainer and such stuff.
5. Enabled http-proxy module for Apache:

   $> a2enmod proxy_http
   $> service apache2 restart

    

6. Add the proxy definition to the Apache directives in ISPConfig:

   ProxyPass /monit/ http://127.0.0.1:2812/ 
   ProxyPassReverse /monit/ http://127.0.0.1:2812/ 
   <Location /monit/>
       Order deny,allow
       Allow from all
       ProxyPassReverseCookiePath / /monit/
   </Location>

    

   The Apache directives can be found in the site administration of the respective website in the options tab as shown below.

   

That’s it! That’s how I setup monit behind Apache proxy. Now I was able to call monit via the following URL in webbrowser:

https://monitoring.ask-sheldon.com/monit/

Finally I put this URL together with the given credentials to the server configuration of ISPConfig (System Tab -> Server Config):

Afterwards the monit monitoring can be seen in ISPConfig backend (Monitor Tab -> Show Monit)