How To Install Nagios on Ubuntu 15.04

Install Nagios on Ubuntu 15.04

This how-to will help you with your install and configuration of Nagios on your Ubuntu 15.04 server. For those of you who didn’t know, Nagios is open-source software that can be used for network and infrastructure monitoring. Nagios will monitor servers, switches, applications, and services. It alerts the System Administrator when something went wrong and also alerts back when the issues have been rectified. Resources that can be monitored include CPU, memory, and disk space loads, log files, temperature, or hardware errors. It can monitor various parameters and problems for services like HTTP, SMTP, DNS, and with the help of plugins, it can be highly extended. Nagios Core was originally designed to run under Linux, although it should work under most other units as well.

This article assumes you have at least basic knowledge of Linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple. I will show you through the step by step installation Nagios in the ubuntu 15.04 server.

Install Nagios on Ubuntu 15.04

Step 1. First, make sure that all your system packages are up-to-date by running these following apt-get commands in the terminal.

Step 2. Install LAMP server.

A Ubuntu 15.04 LAMP server is required. If you do not have LAMP installed, you can follow our guide here. Also, install the dependencies for Nagios:

Step 3. Create users and groups for Nagios.

Step 4. Install Nagios service and Nagios plugins.

Download the latest stable version of Nagios, At the moment of writing this article it is version 4.1.0rc2:

Download the latest nagios-plugins source and install using the following commands:

Configuration Nagios

Step 5. Configure Nagios.

Edit the /usr/local/nagios/etc/objects/contacts.cfg config file with your favorite editor and change the email address associated with the nagiosadmin contact definition to the address you’d like to use for receiving alerts.

Change the email address field to receive the notification:

Step 6. Configure Apache webserver.

Edit the following lines if you want to access Nagios administrative console from a particular IP series, Here, I want to allow Nagios administrative access from series only:

Enable Apache’s rewrite and cgi modules:

Configure Apache authentication:

We need to set up the password for the user nagiosadmin. This username will be used to access the web interface so it is important to remember the password that you will input here. Set the password running the following command and enter the password twice:

Restart Apache for the changes to take effect:

Step 7. Verify and Start Nagios service.

Next, we have to make Nagios start at boot time, so first verify that the configuration file has no errors running the following command:

And you should get the output:

If there are no errors, start Nagios service and make it to start automatically on every boot:

When you try to start the Nagios and got the following error with Nagios init script. To fix this error, copy /etc/init.d/skeleton to /etc/init.d/nagios using the following command:

Edit file /etc/init.d/nagios:

Add the following lines:

Finally, you need to change the permissions:

You can start the Nagios using the following command:

Step 8. Access Nagios from the web browser.

Nagios creates its own apache configuration file /etc/httpd/conf.d/nagios.conf. There is no need to make any changes to it. Simply open URL in browser http://nagios-server-ip/nagios.

When prompted for a username and password you will introduce the username “nagiosadmin” and the password that you entered in step 6. In case you forget this password you can modify it by rerunning the htpasswd command in step 5.

Install Nagios on Ubuntu 15.04

Congratulations! You have successfully installed Nagios. Thanks for using this tutorial for installing Nagios in ubuntu 15.04 systems. For additional help or useful information, we recommend you to check the official Nagios web site.

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