How to Install Checkmk Monitoring Agents on Linux

Last Updated:

In this tutorial, you will learn how to install Checkmk monitoring agents on Linux. Monitoring agents enables remote monitoring of system metrics such as system load, memory and disk usage e.t.c.

In our previous tutorial, we learnt how to install Checkmk monitoring tool on Ubuntu 20.04 system.

How to Monitor IT Infrastructure using Checkmk

If you noticed, when first installed, no host/services are monitored by default installation of Checkmk.

Installing Checkmk Monitoring Agents on Linux

In this tutorial, we will learn how to install Checkmk monitoring agents on Ubuntu, Debian and CentOS systems.

You need to install the agent on the monitoring server as well.

Install Checkmk Monitoring Agents on Ubuntu/Debian

Download Checkmk Agent for Ubuntu/Debian

Checkmk provides an easy way to download the montoring agents for various Operating systems.

On the Checkmk monitoring server web interface, navigate to Setup > Agents > Windows, Linux, Solaris,AIX.

How to Install Checkmk Monitoring Agents on Linux

Install Checkmk Monitoring Agents on Ubuntu/Debian

From the list of available agents, click the third option to download an installer for Ubuntu/Debian systems.

Once you have downloaded the installer, then install it by running the command below;

apt install ./check-mk-agent_2.0.0p12-31293648899edb8d_all.deb

Download and Install Checkmk Agent on CentOS/RHEL

Similarly, download the agent for CentOS/RHEL (RPM) from the list of available agents on the Checkmk UI.

Once you have the Checkmk RPM package, run the command below to install it.

yum localinstall check-mk-agent-2.0.0p12-31293648899edb8d.noarch.rpm

Add Hosts to Checkmk Monitoring Platform

Once you have the agents installed, the next step would to be add these hosts to Checkmk monitoring server.

On the Navigation menu, click Setup > Hosts > Hosts. Such an interface opens up.

add hosts

Click Add host to monitoring.

Adding Localhost/Checkmk Monitoring Server

I will start by adding the Checkmk server, and hence, enter the hostname as localhost.

add localhost

Next, click Save & go to connection tests to test the connectivity to the localhost and verify if the agent is installed.

Sample connection checks;

test connection to host

SNMP check will fail, if no SNMP agents are installed/configured on the remote hosts yet. We are not using SNMP in this setup.

Host Service Discovery

If the connection to the host is okay, proceed to do a service discovery in order to auto-configure all services to be checked on this host.

This will run a full service scan on the host and such output is shown after a short while.

localhost services

To start monitoring services that are currently not monitored, click Fix all.

The monitored services interface now changes like as shown below;

monitored services

Activate pending changes

Next, you need to write the changes.

On the interface, click the notification icon, with the number of changes, on the right. See the highlighted section in the screenshot above.

activate changes 1

Next, click Activate on selected sites to save the changes. Once the changes are activated, you should see progress as success.

Add Remote Hosts to Checkmk Monitoring

For the remote hosts, ensure that TCP port 6556 is open on firewall.

For Ubuntu/Debian systems that have UFW running, you can open the port as follows. Replace CHECKMK-SERVER-IP with Checkmk server IP.

ufw allow from CHECKMK-SERVER-IP to any port 6556 proto tcp comment "Allow Checkmk monitoring"

Once CentOS/RHEL/Rocky Linux, open the port on firewalld. You can create a new zone for monitoring;

firewall-cmd --new-zone=checkmk-monit --permanent
firewall-cmd --zone=checkmk-monit --add-source=CHECKMK-SERVER-IP/MASK --permanent
firewall-cmd --zone=checkmk-monit --add-port=6556/tcp --permanent
firewall-cmd --reload

Next, you can follow the same procedure to enroll the remote hosts that already have the Checkmk agents installed.

In our setup, we have added three hosts in total; localhost, a debian 11 system and a Rocky Linux 8 system.

You can see all hosts under Setup > Hosts > Hosts;

hosts directory

You can also check an overview of all hosts from Monitor > Overview > All Hosts.

all hosts overview 2

You can click on one of the hosts to have an overview of the associated services and view the graphical representation.

Once the service overview page opens up, you can click like memory, to view graphical representation.

memory usage 1

Awesome tool, isn’t it?

Main Dashboard status;

main dashboard hosts status 1

Stay tuned for more tutorials on this awesome tool.


Monitoring Agents

Other Tutorials

Install ELK Stack on Debian 11

Install Osquery on Rocky Linux 8

Install and Configure SNMP on Rocky Linux 8


We're passionate about sharing our knowledge and experiences with you through our blog. If you appreciate our efforts, consider buying us a virtual coffee. Your support keeps us motivated and enables us to continually improve, ensuring that we can provide you with the best content possible. Thank you for being a coffee-fueled champion of our work!

Photo of author
I am the Co-founder of, Linux and the whole FOSS enthusiast, Linux System Admin and a Blue Teamer who loves to share technological tips and hacks with others as a way of sharing knowledge as: "In vain have you acquired knowledge if you have not imparted it to others".

Leave a Comment