Install and Use Monit on AlmaLinux 8

This tutorial intends to teach you to Install and Use Monit Linux Process and Services Monitoring on AlmaLinux 8. Monit is a free and open-source tool that you can manage and monitor a system through the web interface.

You can follow this guide to start your Monit installation on AlmaLinux 8 and start using it by adding a service in your Monit manager and detecting all information about your system hardware.

How To Install and Use Monit on AlmaLinux 8?

Before you start your Monit installation, you must have access to your server as a non-root user with sudo privileges and set up a basic firewall. For this purpose, you can follow this guide on Initial Server Setup with AlmaLinux 8.

Now follow the steps below to complete this guide.

Step 1 – Install Required Packages for Monit

First, you must run the system update by using the following command:

sudo dnf update -y

Then, run the command below to install the required packages and dependencies for Monit:

sudo dnf install zlib-devel pam-devel openssl-devel libtool bison flex autoconf gcc make git epel-release -y

Step 2 – Install and Start Monit on AlmaLinux 8

At this point, you can easily install your Monit manager on AlmaLinux 8 by using the command below:

sudo dnf install monit -y

When your installation is completed, start your Monit service by using the command below:

sudo monit

In your output, you should see:

Output
 New Monit id: c1e1960b7fe7b88cbbd8949636394945
 Stored in '/root/.monit.id'
Starting Monit 5.30.0 daemon with http interface at [localhost]:2812

Also, you can check your Monit service status by using the following command:

sudo monit status

Output
Monit 5.30.0 uptime: 1m

System 'alma.linux'
  status                       OK
  monitoring status            Monitored
  monitoring mode              active
  on reboot                    start
  load average                 [0.06] [0.09] [0.04]
  cpu                          0.2%usr 0.4%sys 0.0%nice 0.0%iowait 0.6%hardirq 0.8%softirq 2.2%steal 0.0%guest 0.0%guestnice
  memory usage                 405.7 MB [10.9%]
  swap usage                   0 B [0.0%]
  uptime                       21h 45m
  boot time                    Sat, 05 Aug 2023 05:42:34
  filedescriptors              832 [0.2% of 377358 limit]
  data collected               Sun, 06 Aug 2023 03:27:20

To enable your Monit service, you can run the command below on AlmaLinux 8:

sudo systemctl enable monit 

Step 3 – How To Configure Monit on AlmaLinux 8?

The Monit program can be configured using the /etc/monitrc file. You need to make some configuration changes to this file.

Enable Monit Listening Port

By default, port 2812 is disabled which is used for communicating with Monit. So you need to enable it. To do this, open the Monit config file by using your favorite text editor, here we use the vi editor:

sudo vi /etc/monitrc

Find the line: set httpd port 2812 

Replace the allow and use address value from localhost to 0.0.0.0 if you want to access the Monit web interface remotely as shown below.

You can also change 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'

When you are done, save and close the file.

To check the Monit configuration on AlmaLinux 8, use the command below:

sudo monit -t

Output
Control file syntax OK

Step 4 – Configure Firewall for Monit

At this point, you need to allow port 2812 through the firewall. To do this, run the command below:

sudo firewall-cmd --permanent --add-port=2812/tcp

Reload the firewall to apply the new rules:

sudo firewall-cmd --reload

Finally, restart the Monit service:

sudo systemctl restart monit

Step 5 – Access Monit Service Manager through Web Interface

At this point, you can access your Monit web interface on AlmaLinux 8 by typing your server’s IP address in your web browser followed by 2812:

http://your-server-ip-address:2812

You will see the sign-in screen. Enter the admin user and password you have defined in the Monit config file and click Sign in.

You will see the following screen:

Step 6 – Add Services In Monit on AlmaLinux 8

At this point, you can create a service file for an application to get monitored.

For example, if you want to monitor Nginx, you can create a config file in the /etc/monit.d directory:

sudo vi /etc/monit.d/nginx-monitor

check process nginx with pidfile /run/nginx.pid
start program "/usr/bin/systemctl start nginx.service"
stop program "/usr/bin/systemctl stop nginx.service"
if failed port 80 protocol http then restart

When you are done, save and close the file.

Then, check for the Monit file syntax:

sudo monit -t

Output
Control file syntax OK

Reload the Monit service on AlmaLinux 8:

sudo monit reload

Output
Reinitializing monit daemon

In your Monit service manager, you should see:

For more information, you can visit the Monit Docs page.

Conclusion

At this point, you have learned to Install and Use Monit Manager Service on AlmaLinux 8 and add services to your Monit Manager. Hope you enjoy using it.

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How to install Virtualizor on AlmaLinux

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