How to Install and Use Monit on Ubuntu 20.04

Introduction

Before we begin talking about how to install Monit on Ubuntu 20.04, let's briefly understand – What is Monit?

Monit is an open-source monitoring tool for system stability and performance. With Monit, you can proactively track vital system metrics, detect issues, and automatically take corrective actions.

This versatile solution offers real-time alerts, resource usage monitoring, process management, and more. Monit ensures optimal uptime and reduces downtime risks, making it an indispensable tool for system administrators and businesses. Boost your server's reliability and streamline operations with Monit's robust monitoring capabilities.

In this tutorial, you will install the Monit Monitoring system on Ubuntu 20.04 LTS Jammy JellyFish to monitor a server or desktop using its GUI web interface. We will also address a few FAQs on how to install Monit on Ubuntu 20.04.

Advantages of Monit

1. Proactive Monitoring: Monit helps you detect and address issues before they impact your systems, ensuring optimal performance and uptime.
2. Automated Actions: With Monit, you can automate corrective actions to resolve problems swiftly and minimize downtime.
3. Real-time Alerts: Receive instant notifications about critical events and system failures, allowing you to respond promptly.
4. Resource Monitoring: Keep track of CPU usage, memory utilization, disk space, and more to optimize resource allocation.
5. Process Management: Monit allows you to control and manage processes, restart services, and ensure smooth operation of your applications.

Installing M/Monit monitoring on Ubuntu 20.04 Linux

Step 1 – Update Ubuntu 20.04

Let's install the most recent updates on our Ubuntu 20.04 system using the system update command. Along with it, the APT package manager cache will be rebuilt.

sudo apt update && sudo apt upgrade

Step 2 – Install Monit on Ubuntu 20.04

Let's install Monit Monitoring on Ubuntu 20.04 after executing the system update command, since it is accessible for installation through the default system repository. Therefore, there is no need to search for a third-party repository for updates.

sudo apt-get install monit

Step 3 – Check service Status & Version of Monit

After the installation is finished, let's see if the service is functioning properly in the background.

sudo systemctl status monit --no-pager -l

Start it using the following command if it isn't already running.

sudo systemctl start monit

Check the Monit version using:

sudo monit --version

Step 4 – Configuration File

The /etc/monit/monitrc file is used to configure the Monit program. There are several sample settings, some of which are commented out, self-explanatory, or have help messages in their comments. We advise against changing these settings directly in the file. For preferred settings, it is advisable to create a new one using sudo nano /etc/monit/conf.d/.

Step 5 – Enable m/Monit httpd port on Ubuntu

In order to communicate with Monit, port 2812 must be enabled; this can be done by modifying the configuration file.

sudo nano /etc/monit/monitrc

Locate the line: set httpd port 2812

For the lines that follow, remove the # tag at that point. If you want to use the Monit web interface remotely, as indicated in the screenshot, you must change the allow and use address value from localhost to 0.0.0.0.

Additionally, you have the option of changing the default password for the admin that is monit.

set httpd port 2812 and
use address 0.0.0.0 # only accept connection from localhost (drop if you use M/M>
allow 0.0.0.0/0 # allow localhost to connect to the server and
allow admin:monit # require user 'admin' with password 'monit'

Press Ctrl+X, type – Y, then hit Enter to save the file.

Step 6 – Check and load

Use the following command to verify that configuration files are error-free:

sudo monit -t

# If there are no errors, you will receive the following feedback:

# Control file syntax OK

Step 7 – Enable Monit service on Linux

Run the command to enable the Monit service to start automatically when the system boots to enable it because it is not enabled by default.

sudo /lib/systemd/systemd-sysv-install enable monit

Restart it once

sudo systemctl restart monit

Step 8 – Check Status

Run the following command to ensure everything is in working order.

sudo monit status

Step 9 – Permit Monit port in Ubuntu 20.04 firewall

Allow its port or service in the firewall to access the public network to access the Monit web interface from a host other than your local one.

sudo ufw allow 2812

Step 10 – Access Web Interface

Launch a web browser on a local or remote computer that has access to the server's or computer's IP address, where the Monit Monitor system is installed. Additionally, direct it to http://your-server-ip-address:2812.

Username and password are required.

Step 11 – Add services to Monitor in Monit

For an application to be monitored, you may either build a service file or utilize one of the pre-configured ones found in the M/Monit folder.

There are multiple pre-made files for different popular server services, including the following in the directory /etc/monit/conf-available/:

acpid, at, mdadm, mysql, openntpd, pdns-recursor, rsyslog, snmpd,
apache2, cron, memcached, nginx, openssh-server, postfix and smartmontools.

It is necessary to build and activate a soft link to the service file in the /etc/monit/conf-enabled/ directory for Monit to take over the settings for the desired service.

For example:

With the help of its pre-configured file, we want to monitor Nginx. Thus, for that-

Syntax:

sudo ln -s /etc/monit/conf-available/service-file  /etc/monit/conf-enabled/

example for Nginx:

sudo ln -s /etc/monit/conf-available/nginx /etc/monit/conf-enabled/

The Monit daemon must be reloaded for the changes to take effect.

sudo monit reload

We may enable other services in the same way.

Manually Add Service

Now, if you wish to manually add a service, you must first create a file for it. For instance, you might want to use sensors to gather all hardware-related data about your system.

sudo apt install lm-sensors 

sudo nano /etc/monit/conf-available/sensors

Add:

check program sensors with path /usr/bin/sensors
if status != 0 then alert

Save the file: Ctrl+X, Y, and press the Enter Key.

Enable it:

sudo ln -s /etc/monit/conf-available/sensors /etc/monit/conf-enabled/

Reload Monit:

sudo monit reload

FAQs to Install and Use Monit on Ubuntu 20.04

Conclusion

We hope this detailed tutorial helped you understand how to install Monit on Ubuntu 20.04. Check the official documentation to learn more about it.

If you have any queries or doubts, please leave them in the comment below. We'll be happy to address them.