Checkmk on RHEL/AlmaLinux 9

How to Install Checkmk Raw on AlmaLinux 9

Checkmk is a easy to setup IT monitoring solution that provides deep insights into your infrastructure. This guide will walk you through installing the latest Checkmk Raw edition on AlmaLinux 9. Other RHEL 9 based distros should work too, as they are very similar.

Step 1: Update Your System

Before installing any new software, it is best practice to update your system packages to ensure you have the latest security patches and dependencies:

dnf update -y

Step 2: Install Wget

Wget is required to download the Checkmk package. If it is not already installed, run the following command:

dnf install wget -y

Step 3: Download the Latest Checkmk Raw Package

Visit the official Checkmk Download Page to get the latest version available. For this guide, we will be using version 2.3.0p25 for Red Hat 9:

wget https://download.checkmk.com/checkmk/2.3.0p25/check-mk-raw-2.3.0p25-el9-38.x86_64.rpm

Step 4: Install Checkmk Raw

Once the package is downloaded, install it using the dnf package manager:

dnf install check-mk-raw-2.3.0p25-el9-38.x86_64.rpm -y

Step 5: Create a Monitoring Site

The Name of the site will be part of your URL (http://your-server-ip/sitename)

As this indicates, you can configure multiple sites in a single Checkmk instance

After installation, create a monitoring site. Replace sitename with your preferred name:

omd create sitename

Step 6: Start the Monitoring Site

To start the Checkmk monitoring site, run:

omd start sitename

Configuring firewall-cmd

Now you have to open up port 22 (to not lock yourself out), 80 and 443, to do so:

firewall-cmd --permanent --add-service=http --add-service=https --add-service=ssh
firewall-cmd --reload

You can check if the ports are open with:

firewall-cmd --list-all

Accessing Checkmk

Once started, you can access the Checkmk web interface by navigating to (replace „sitename“ depending on Step 5):

http://your-server-ip/sitename

Conclusion

You have successfully installed and started Checkmk Raw on RHEL 9. You can now begin configuring hosts, services, and alerts to monitor your infrastructure.