What Monit?

Let me explain about the utility. It has the ability to start a process if it is not running, restart a process if not responding and stop a process if uses high resources. In simple words it’s a helpful program that automatically monitors and manages server programs/resources to ensure that they stay online 24/7 while maintaining the correct file size, checksum and permissions. It’s important system monitoring tool anyone would like to have in their mission critical systems. With the web interface given you could see what’s going on with your system. In this article I’ll be covering end-to-end and providing you value links to be bookmarked in your browser(tongue-out-face).

What's monit

from http://mmonit.com/monit/

Why?

It can do a lot more than you think, it can do maintenance as well as fix the errors in an error situation in below sections.

  • Proactive
  • Processes
  • Files, Dirs and Filesystems
  • Cloud and Hosts
  • Programs and scripts
  • System

For more info on above sections please refer this link. Also check out it’s design philosophy here.

Installing

Let’s apt-get to install. Beauty of linux right(happy-face).

installing monit

installing monit

Okay now time to check whether it’s running. Type the below command.

Most probably just like me you should get the error below.

monit error

installation error

Let’s fix it by editing monitrc file.

now uncomment below lines starting from line 118.

now you will able to access the monit web interface by navigating to the http://localhost:2812. Also try monit status which will give the below output.

monit status

status command output

Configuring

Configurations can be specified in the /etc/monit/monitrc file or using individual files in /etc/monit/conf.d/ directory. In this article, I’ll be using monitrc.

edit /etc/monit/monitrc. In the file as you can see By default, it is set up to check that services are running every 2 minutes which should good enough for you. You can change that according to the criticality of the system. We’ll be using basic configurations. As always you can dive in more. Let’s add below lines to monitor Apache and MySQL.

Below is to configure Apache web server.

Below is to configure MySQL server.

Now log into the web interface by navigating to the http://localhost:2812. All must be good as shown below.

Monit Web Interface : http://localhost:2812

Monit Web Interface : http://localhost:2812

Also check out logs as well.

if you are worrying about other configuration such as NginX, SSHD, PostgreSQL etc you can refer Real-world configuration examples. Documentation contains all the configuration in the world you need. If you have any questions let me know in the comments below. Your feedback is highly appreciated(happy-face).

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