In this tutorial we will show you how to install Nagios on Ubuntu 20.04 LTS. For those of you who didn’t know, Nagios is an open source monitoring tool used to monitor different Linux Machines or different client hosts. It monitors the HTTP, FTP, SSH, SMTP etc along-with the CPU usage, RAM, Disk Usage and different process that are being running.
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 and assumes you are running in the root account, if not you may need to add ‘sudo’ to the commands to get root privileges. I will show you through the step by step installation Nagios on a Ubuntu 20.04 (Focal Fossa) server.
Install Nagios on Ubuntu 20.04 LTS Focal Fossa
Step 1. First make sure that all your system packages are up-to-date by running these following apt commands in the terminal.
1 2 3 | sudoaptupdate sudoaptupgrade sudoaptinstallbuild-essentialapache2phpopensslperlmakephp-gdlibgd-devlibapache2-mod-phplibperl-devlibssl-devdaemonwgetapache2-utilsunzip |
Add the user to the Apache web server group:
1 2 3 4 | sudouseraddnagios sudogroupaddnagcmd sudousermod-a-Gnagcmdnagios sudousermod-a-Gnagcmdwww-data |
Now, download the Nagios from official page or you can get it by the below command through terminal:
1 2 3 4 | cd/tmp wgethttps://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.5.tar.gz tar-zxvf/tmp/nagios-4.4.5.tar.gz cd/tmp/nagios-4.4.5/ |
Then, Compile the Nagios from the source code:
1 2 3 4 5 6 | sudo./configure--with-nagios-group=nagios--with-command-group=nagcmd--with-httpd_conf=/etc/apache2/sites-enabled/ sudomakeall sudomakeinstall sudomakeinstall-init sudomakeinstall-config sudomakeinstall-commandmode |
Nagios places configuration files in the /usr/local/nagios/etc directory. Now, with the help of your favorite editor edit the file:
1 | sudonano/usr/local/nagios/etc/objects/contacts.cfg |
Change the email address field to receive the notification:
1 2 3 4 5 6 7 8 | definecontact{ contact_name nagiosadmin ;Shortnameofuser use generic-contact ;Inheritdefaultvaluesfromgeneric-contacttemplate(definedabove) alias NagiosAdmin ;Fullnameofuser email admin@idroot.us ;<<*****CHANGETHISTOYOUREMAILADDRESS ****** } |
Install the Nagios web interface using the below command:
1 | sudomakeinstall-webconf |
Then create a user account as “nagiosadmin” for accessing the Nagios web interface. Make sure to save the password you provided on safe place or keep in mind as it will be needed later:
1 | sudohtpasswd-c/usr/local/nagios/etc/htpasswd.usersnagiosadmin |
After it run the below command:
1 | sudoa2enmodcgi |
Next, Restart Apache for the changes to take effect:
1 | sudosystemctlrestartapache2 |
Next steps, Download latest nagios-plugins source and install using following commands:
1 2 3 4 | cd/tmp wgethttps://nagios-plugins.org/download/nagios-plugins-2.3.3.tar.gz tar-zxvf/tmp/nagios-plugins-2.3.3.tar.gz cd/tmp/nagios-plugins-2.3.3/ |
Compile and install the plugins:
1 2 3 | sudo./configure--with-nagios-user=nagios--with-nagios-group=nagios sudomake sudomakeinstall |
Double check the configuration done above by hitting the given command and make sure all configuration pre-checks are okay:
1 | sudo/usr/local/nagios/bin/nagios-v/usr/local/nagios/etc/nagios.cfg |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | Output: NagiosCore4.4.5 Copyright(c)2009-presentNagiosCoreDevelopmentTeamandCommunityContributors Copyright(c)1999-2009EthanGalstad LastModified:2019-08-20 License:GPL Website:https://www.nagios.org Readingconfigurationdata... Readmainconfigfileokay... Readobjectconfigfilesokay... Runningpre-flightcheckonconfigurationdata... Checkingobjects... Checked8services. Checked1hosts. Checked1hostgroups. Checked0servicegroups. Checked1contacts. Checked1contactgroups. Checked24commands. Checked5timeperiods. Checked0hostescalations. Checked0serviceescalations. Checkingforcircularpaths... Checked1hosts Checked0servicedependencies Checked0hostdependencies Checked5timeperiods Checkingglobaleventhandlers... Checkingobsessivecompulsiveprocessorcommands... Checkingmiscsettings... TotalWarnings:0 TotalErrors: 0 |
Then, enable Nagios service to start automatically at system startup:
1 2 | sudosystemctlenablenagios sudosystemctlstartnagios |
Nagios will be available on HTTP port 80 by default. Open your favorite browser and navigate to http://your-domain.com/nagios or http://your-server-ip/nagios and complete the required the steps to finish the installation. When prompted for username and password you will introduce the username “nagiosadmin” and the password that you entered in step 5.
Congratulation’s! You have successfully installed Nagios. Thanks for using this tutorial for installting Nagios monitoring tool in Ubuntu 20.04 LTS (Focal Fossa) systems. For additional help or useful information, we recommend you to check the official Nagios website.
