How to Add Linux Host in Zabbix Server for Monitoring

In the previous article, we have covered how to Install Zabbix Server on CentOS 8. In this guide, we go a step further and show you how you can add a Linux host to the Zabbix Server so that we can monitor various metrics such as CPU load, memory utilization, swap usage, and disk utilization to mention a few.

But first, we need to install the Zabbix Agent on the remote host which is going to ship the metrics of the remote system to the Zabbix server for monitoring. In this guide, we will install the Zabbix agent on Ubuntu 20.04 LTS and CentOS 8.

How to Install Zabbix agent on Ubuntu Linux?

To get started with the installation of Zabbix agent, follow the steps below:

Step 1) Adding the Zabbix repository and Installing Zabbix agent

By default, the Zabbix repository is not included in the Ubuntu repository.  We, therefore, need to manually add it before installing the Zabbix agent. At the time of penning down this guide, the latest version of Zabbix is Zabbix 5.0. Therefore, we are going to add the Zabbix agent that corresponds to that version.

To so do, first download the repository’s Debian package:

For Ubuntu 20.04 (Focal Fossa)

$ wget https://repo.zabbix.com/zabbix/5.0/ubuntu/pool/main/z/zabbix-release/zabbix-release_5.0-1%2Bfocal_all.deb

After the package is downloaded, update the package list and install  the zabbix-agent using the dpkg package manager as shown:

$ sudo apt update
$ sudo dpkg -i zabbix-release_5.0-1+focal_all.deb

For Ubuntu 18.04 (Bionic Beaver)

For Ubuntu 18.04, execute the commands below to add the repository

$ wget https://repo.zabbix.com/zabbix/5.0/ubuntu/pool/main/z/zabbix-release/zabbix-release_5.0-1%2Bbionic_all.deb
$ sudo apt update
$ sudo dpkg -i zabbix-release_5.0-1+bionic_all.deb

For Ubuntu 16.04 (Xenial Xerus)

$ wget https://repo.zabbix.com/zabbix/5.0/ubuntu/pool/main/z/zabbix-release/zabbix-release_5.0-1%2Bxenial_all.deb
$ sudo apt update
$ sudo dpkg -i zabbix-release_5.0-1+xenial_all.deb

Step 2) Configure Zabbix agent

With the successful installation of the Zabbix agent, we need to make a couple of tweaks for the remote system to communicate with the Zabbix server. We are going to make a few adjustments in the configuration file which is /etc/zabbix/zabbix_agentd.conf

In the file locate the Server and hostname attributes and set them to correspond to the server’s parameters. In our case, we have:

Server=10.128.0.10
hostname=ubuntu20-04

Once done, save & exit the configuration file.

Also, ensure that you can reach the Zabbix server by pinging its IP address and hostname.

For the changes to come into effect, restart the Zabbix-agent as shown:

$ sudo systemctl restart zabbix-agent

To ensure it is running, check its status using the command:

$ sudo systemctl status zabbix-agent

Zabbix-agent-status-ubuntu-linux

From the output, it’s clear that the Zabbix agent is up and running.

Step 3) Configure the firewall rules for zabbix-agent

Finally, we need to configure the firewall to open port 10050 which the zabbix-agent listens on. Therefore, run the commands below:

$ sudo ufw allow 10050/tcp
$ sudo ufw reload

To confirm that the port is open, run:

$ sudo ufw status

Ufw-zabbix-agent-rules-ubuntu-linux

Up to this mark, you have successfully installed the Zabbix agent on Ubuntu and your system is ready to be added to the Zabbix server for monitoring.

How to install zabbix agent on CentOS 8 / RHEL 8?

For CentOS 8 / RHEL 8 systems, the steps for installing the Zabbix agent are pretty much similar.

Step 1) Adding the Zabbix repository

Begin by manually adding the repository since the Zabbix repository is not included by default on AppStream repo.

$ sudo dnf install https://repo.zabbix.com/zabbix/5.0/rhel/8/x86_64/zabbix-agent-5.0.0-1.el8.x86_64.rpm

Install-Zabbix-agent-CentOS8

Press Y to finish the installation.

Step 2) Configure zabbix agent

As demonstrated earlier, a few changes need to be made in the agent’s configuration which is /etc/zabbix/zabbix_agentd.conf

As before, set the  Server and hostname directives to match the Zabbix server’s parameters as shown:

Server=10.128.0.10
hostname=centos-8

Once done, save & exit the configuration file. Next, restart the Zabbix-agent daemon and confirm whether it’s running:

$ sudo systemctl restart zabbix-agent
$ sudo systemctl status zabbix-agent

Zabbix-Agent-Status-CentOS8

Step 3) Configure the firewall rule for zabbix-agent

Finally, to allow Zabbix-agent to establish communication with the Zabbix Server and vice versa ,  configure the firewall by running  the commands as shown:

$ sudo firewalld --add-port=10050/tcp --permanent
$ sudo firewalld --reload

Adding or Registering Remote Linux Host in Zabbix Server

Login to your Zabbix Server portal using admin user’s credentials .To add a host on the Zabbix server, click on Configuration –> Hosts.

On the far top- right end, click on the ‘Create host’ button

Create-Host-Entries-Zabbix-Portal

On the page that appears, fill out the remote Linux’s details as listed:

  • Hostname
  • Visible name
  • IP address
  • Description

Specify-Linux-Server-Details-Zabbix-Portal

Next, click on the ‘select’ button next to the ‘Groups’ text field. On the ‘Host groups’ list, click on ‘Linux servers’ and then click ‘Select’.

Choose-Linux-Servers-Host-Groups-Zabbix

As you can see, the group has been added.

Linux-Servers-Group-Zabbix

We also need to add a template for our server. So, click on the ‘Templates’ menu option.

Hosts-Templates-Zabbix

On the ‘Templates’ list that appears, click on ‘Template OS Linux by Zabbix agent’ and hit the ‘Select’ button.

Choose-Template-OS-Linux-Zabbix-Agent

This takes you back to the home screen and there you can see that your new host system has been added.

Ubuntu-20-04-added-Zabbix-Portal

To add the CentOS-8 system, repeat the same steps described.

Graphing statistics of the remote hosts

To represent system metrics in a graphical form, click on ‘Monitoring’  –> ‘Hosts

Next, click on the host you want to graph and select the ‘graph’ option from the pull-up menu.

Host-Monitoring-Graph-Option-Zabbix-Portal

Zabbix server will begin generating various graphs representing various system metrics such as Processes, CPU load, and network traffic statistics to mention a few.

Host-Process-Graph-Zabbix-Server

Scroll down to view other graphs displaying various metrics as shown below.

Host-Network-Graph-Zabbix-Server

We have successfully added 2 Linux host systems to the Zabbix server and managed to graph various system metrics. We appreciate your feedback. Give it a try and let us know your experience.

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