Beginner’s guide to Installing & Configuring NAGIOS server

Hello Linux-fanatics, in this tutorial we will learn to installing and configuring Nagios server. Nagios server (AKA nagios core) is a very useful, open-source monitoring tool. With the help of Nagios server, we can monitor stats like ram usage, cpu usage, hdd usage along with other parameters of a number of machines/servers on single screen. If something goes wrong , its sends us warning by using sound or sending a mailto configured users or we can even configure Nagios to send a sms to a phone number.

(Recommended Read: Real Time Linux server monitoring with GLANCES monitoring tool )

(Also Read: Easy guide to setup Nagios monitoring using SSH (check_by_ssh))

Pre-requisites

Before we can install Nagios , we need some packages like httpd, php, gcc, glibc, glibc-comman & GD on our system.

To install all these packages, run following

After all the packages are installed, we will now download the Nagios & its plugins source file. As of writing of this tutorial, Nagios 4.2.4  & Plugins 2.1.4 are the latest. You can directly download the files using link below or you can use wget also to get these files

Now we will start with installation of Nagios....

Installation

Step 1 – Create  a user & group for Nagios

We will add a user nagios & a group nagcmd

Now, we will add nagios & apache to nagcmd group

Step2- Extracting Nagios files

We will now extract the nagios & plugins files on our system

Step 3- Configuring Nagios server

Now that we have extracted the Nagios file, we will now go to the extracted folder & compile those files to install Nagios server

after it’s completed, we will now run make & make install to complete our installation

once these steps are done, we need to install init –scripts, commandmode & also need to install some sample  Nagios files

Step4 – Configuring Web-Interface

Once all the above installations are complete, we can now configure web-interface where we will do all the monitoring. To install web-interface, run the following command

Our web-interface is now installed and a default user “nagiosadmin” has been created. We will now assign password to user “nagiosadmin”

Step 5- Setting an email for sending alerts

To set an email to receive alerts , open

and enter an email address.

(Also Read: Complete monitoring solution : Install OMD (Open Monitoring Distribution))

Step 6- Installing the Nagios Plugins

Now, it’s time to install Nagios plugins

Step 7 – Verify Nagios files

In the last step of Nagios server installation, we will verify Nagios configuration file against a sample configuration file to make sure all the settings are Okay

If all the settings made are correct you should not receive any error.

Now restart nagios server & httpd server

Step 8- Logging into Web-interface

Open your browser & enter http://localhost/Nagios or http://IP-address/Nagios  in your address bar & you will be asked to enter the username & password. Upon entering the credentials, you can now see your Nagios Web-interface.

When you see service overview page, we can only see services of our localhost . That is because we have not added other host services on Nagios.

We now end this tutorial on installing and configuring nagios server. In our next tutorial, we will discuss how can we add Windows hosts & Linux hosts to Nagios server. Please share your queries/comments down below in the comment box.