Install Monit System Monitor on Ubuntu 18.04 | 16.04 LTS

This brief tutorial shows students and new users how to install and configure Monit monitoring package on Ubuntu 16.04 | 17.10 | 18.04 LTS servers.

For those who don’t know about Monit, is an open source utility for managing and monitoring Linux systems, including Ubuntu. It can automate, maintain and repair Linux services, including restoring and restarting them. . A complete enterprise grade server and log monitoring system.

This post will show you how to perform a basic configuration after installing. You’ll also be able to logon to Monit server once installed.

For more about Monit, please visit its homepage.

When you’re ready, continue below with the steps:

Step 1: Install Monit Package

To install Monit, simply run the commands below on Ubuntu server. Most Linux distributions include Monit. Please consult with your package manager. You may also want to check that they have a recent Monit version.

sudo apt update
sudo apt install monit

After installing Monit, the commands below can be used to stop, start and enable Monit service.

sudo systemctl stop monit.service
sudo systemctl start monit.service
sudo systemctl enable monit.service

Step 2: Configure Monit Service

Monit configuration files are located under /etc/monit/ directory. The main configuration file is /etc/monit/monitrc and has a basic setup configured in it. You’ll need to make some changes to suit your environment.

By default all files located on /etc/monit/conf.d/ and /etc/monit/conf-enabled/ are read by monit when the service is started.  Use the /etc/monit/conf.d/ directory to put all your monitoring configuration files in it.

You can have as many files as you want. or grop each service into single file.

Open Monit main config file and make the highlighted changes below, then save the file.

sudo nano /etc/monit/monitrc

The highlighted changes will allow HTTP access to Monit web interface.

## Monit has an embedded HTTP interface which can be used to view status of
## services monitored and manage services from a web interface. The HTTP
## interface is also required if you want to issue Monit commands from the
## command line, such as 'monit status' or 'monit restart service' The reason
## for this is that the Monit client uses the HTTP interface to send these
## commands to a running Monit daemon. See the Monit Wiki if you want to
## enable SSL for the HTTP interface.
#
 set httpd port 2812 and
     use address localhost  # only accept connection from localhost
     allow localhost        # allow localhost to connect to the server and
     allow admin:monit      # require user 'admin' with password 'monit'
#     #with ssl {            # enable SSL/TLS and set path to server certificate
#     #    pemfile: /etc/ssl/certs/monit.pem
#     #}

With the settings above, you should be able to logon to Monit server via the localhost name or IP and username: admin, password: monit

Save your changes and exit.

Restart Monit service by running the commands below:

sudo systemctl restart monit.service

Step 3: Access Monit Web Portal

Now that Monit server is installed and access is allowed from the local machine, use the address below to access Monit portal.

with username: admin and password monit as defined in the configuration file above.

By default not much are being monitored by Monit. you can add custom services to be monitored by creating them in the /etc/monit/conf.d/ directory. For example, to monitor Apache2 service, create a custom config file called apache2.conf in the /etc/monit/conf.d/ directory.

sudo nano /etc/monit/conf.d/apache2.conf

Then add the lines below:

# Apache configuration
check process apache2 with pidfile /run/apache2/apache2.pid
    start program = "/bin/systemctl start apache2" with timeout 60 seconds
    stop program  = "/bin/systemctl stop apache2"
    restart program = "/bin/systemctl restart apache2" with timeout 120 seconds

Save the file and run the commands below to Monit to monitor Apache2.

sudo monit check -t
sudo monit reload
sudo monit start all

Check this page for Monit examples of how to configure custom configurations.  

Now you should see Apache2 service initializing / running in the portal online.

That’s it!

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