Nagios Network Monitoring System Setup in Ubuntu

Sponsored Link
Nagios is a host and service monitor designed to inform you of network problems before your clients, end-users or managers do. It has been designed to run under the Linux operating system, but works fine under most *NIX variants as well. The monitoring daemon runs intermittent checks on hosts and services you specify using external "plugins" which return status information to Nagios. When problems are encountered, the daemon can send notifications out to administrative contacts in a variety of different ways (email, instant message, SMS, etc.). Current status information, historical logs, and reports can all be accessed via a web browser.

WARNING: "this tutorial is meant for users that have a good knowledge of development tools and manual installation process and will be hardly supported by the Ubuntu community. Standard supported procedure are to install packages from the official repositories, not to compile them by hand".

Install Nagios in Ubuntu

This Tutorial is intended to provide you with simple instructions on how to install Nagios from source (code) on Ubuntu and have it monitoring your local machine inside of 20 minutes.

If you follow these instructions, here's what you'll end up with:

Nagios and the plugins will be installed underneath /usr/local/nagios

Nagios will be configured to monitor a few aspects of your local system (CPU load, disk usage, etc.)

The Nagios web interface will be accessible at http://localhost/nagios/

Required Packages

Make sure you've installed the following packages on your Ubuntu installation before continuing.

Apache 2
GCC compiler and development libraries
GD development libraries

Preparing Your System

First you need to install the following packages

sudo apt-get install apache2

sudo apt-get install build-essential

sudo apt-get install libgd2-xpm-dev

1) Create Account Information

Become the root user.

sudo -s

Create a new nagios user account and give it a password.

#/usr/sbin/useradd nagios

#passwd nagios

On Ubuntu server edition , you will need to also add a nagios group (it's not created by default). You should be able to skip this step on desktop editions of Ubuntu.

#/usr/sbin/groupadd nagios

#/usr/sbin/usermod -G nagios nagios

Create a new nagcmd group for allowing external commands to be submitted through the web interface. Add both the nagios user and the apache user to the group.

#/usr/sbin/groupadd nagcmd

#/usr/sbin/usermod -G nagcmd nagios

#/usr/sbin/usermod -G nagcmd www-data

2) Download Nagios and the Plugins

Create a directory for storing the downloads.

#mkdir ~/downloads

#cd ~/downloads

Download the source code tarballs of both Nagios and the Nagios plugins (visit for links to the latest versions). At the time of writing, the latest versions of Nagios and the Nagios plugins were 2.10 and 1.4.10, respectively.



3) Compile and Install Nagios

Extract the Nagios source code tarball.

#cd ~/downloads

#tar xzf nagios-2.10.tar.gz

#cd nagios-2.10

Run the Nagios configure script, passing the name of the group you created earlier like so:

#./configure --with-command-group=nagcmd

Compile the Nagios source code.

#make all

Install binaries, init script, sample config files and set permissions on the external command directory.

#make install

#make install-init

#make install-config

#make install-commandmode

Don't start Nagios yet -- there's still more that needs to be done...

4) Customize Configuration

Sample configuration files have now been installed in the /usr/local/nagios/etc directory. These sample files should work fine for getting started with Nagios. You'll need to make just one change before you proceed...

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.

#vi /usr/local/nagios/etc/objects/contacts.cfg

5) Configure the Web Interface

Install the Nagios web config file in the Apache conf.d directory.

#make install-webconf

Create a nagiosadmin account for logging into the Nagios web interface. Remember the password you assign to this account -- you'll need it later.

#htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

Restart Apache to make the new settings take effect.

#/etc/init.d/apache2 reload

6) Compile and Install the Nagios Plugins

Extract the Nagios plugins source code tarball.

#cd ~/downloads

#tar xzf nagios-plugins-1.4.10.tar.gz

#cd nagios-plugins-1.4.10

Compile and install the plugins.

#./configure --with-nagios-user=nagios --with-nagios-group=nagios


#make install

7) Start Nagios

Configure Nagios to automatically start when the system boots.

#ln -s /etc/init.d/nagios /etc/rcS.d/S99nagios

Verify the sample Nagios configuration files.

#/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

If there are no errors, start Nagios.

#/etc/init.d/nagios start

8) Login to the Web Interface

You should now be able to access the Nagios web interface at the URL below. You'll be prompted for the username (nagiosadmin) and password you specified earlier.


Click on the "Service Detail" navbar link to see details of what's being monitored on your local machine. It will take a few minutes for Nagios to check all the services associated with your machine, as the checks are spread out over time.

9) Other Modifications

If you want to receive email notifications for Nagios alerts, you need to install the mailx (Postfix) package.

#apt-get install mailx

You'll have to edit the Nagios email notification commands found in /usr/local/nagios/etc/commands.cfg and change any ‘/bin/mail' references to ‘/usr/bin/mail'. Once you do that you'll need to restart Nagios to make the configuration changes live.

#/etc/init.d/nagios restart

Sponsored Link

You may also like...

92 Responses

  1. Thanks alot for this artical its helped me alot with what I needed, its straight forward, easy to use and noob friendly 😀


  2. Sum Yung Gai says:

    Perhaps instead of writing this manual you could have invested a little more time to just creating a simple Ubuntu package for apt and submit it for review instead – would have been a much more useful use of your time for the community at-large.

  3. Naz says:

    I followed these instructions. Fantastic. Many Thanks

  4. Shlafik says:

    Great HOW TO.
    Thanks a lot!

  5. Brandon Perry says:

    you should also chsh to /bin/false or something for the nagios user

  6. Steve Mustafa says:

    Nice thanks. I would have added also installing php since its required and since you’ve already mentioned installing apache, otherwise, smooth like silk 🙂

  7. lcd monitor deals says:

    great, user friendly guide, i’ve been looking for something like this. I like how detailed it is. thanks!

  8. Nuno says:

    Hi, it is indeed a good walk through but, i had no errors installing and configuring everything but when i open the web browser for the nagios administration page, i cannot view it it just gives me a file for download and i cannot view the page. it asks me for a username and password before it gives the file for downloading, the file contains html information. i think is something related with apache.

    can anyone help me please?
    this is not the first time this happens to me and i cannot solve it.

  9. fersil says:

    Nuno, tray this:
    htpasswd -c /etc/nagios/htpasswd.users nagios
    htpasswd2 -c /etc/nagios/htpasswd.users nagios

    boa sorte

  10. Odyas says:

    I did not get the objects directory after I followed all the steps, am I missing something?

    My directory only goes as far as
    Contents are
    Any help please?

  11. Denise Wyly says:

    Could you explain more about the second paragraph.

  12. I have the same thing:
    My directory only goes as far as
    Contents are
    Any help please?

  13. cerealmonster says:


    I was running into the same issue, and I discovered I had forgot to install the PHP package on the nagios server. I ran apt-get install php5-gd, rebooted apache and rebooted nagios.

  14. Chris says:

    5) Configure the Web Interface

    Install the Nagios web config file in the Apache conf.d directory.

    #make install-webconf

    WHAT file and WHERE do you execute this? I have tried 10 times and ALWAYS get the same ERROR. Nothing to execute as commands not there.

    Why not say WHERE and HOW to execute this. and WHAT file. This is why open source doesn’t work instructions are ALWAYS Half given and it is expected that we all created the software. COMPLETE instructions are requested

  15. sfcg says:

    This is an awesome article. I was able to bring up the app no problem. I’ve read nearly 100 pages in a nagios manual and learned all about the objects, and the cfg files and how they interact.

    I’m however running into a problem where the web interface is telling me I don’t have permission for anything:

    “It appears as though you do not have permission to view information for any of the hosts you requested…”

    I get this for all pages that are supposed to display objects.

    I followed the intructions here:

    But no dice. Any input?



  16. sfcg says:

    LOL. Nevermind. I just authorized my user for everything in cgi.cfg.



  17. ghostmac says:

    I just wanted to say thank for a great tutorial! Worked like a charm. For those who follow this and get handed a file when attempting to access Nagios via a browser for the first time, you need to install PHP (apt-get install php5-gd).

  18. thiyagi says:

    thanks for the tutorial..

  19. Jack says:

    This article is just perfect!

  20. nagnoob says:


    Cool article, followed it step by step but got this: –
    root@ubuntu:/usr/local/nagios/etc# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
    bash: /usr/local/nagios/bin/nagios: No such file or directory

    There is no bin directory in .usr/local/nagios.


  21. Bob Conner says:

    I am just curious what makes them different?(If there even is a difference).

    What effect does the Oxygen have on Hydrogen?

    Is HHO still explosive?

    Also is HHO made by putting negative and positive charge into water,which then causes the water to bubble is this HHO?(or something else?)

    –Thanks ahead of time.

  22. Nooby says:

    Hi Gays,

    I followed these instructions. It seems like everything is OK
    But, when I try to start nagios: “/etc/init.d/nagios start”
    I got following massage:

    “su:Permission denined

    I try to start nagios as a root.
    Do you have any idea what is the problem ?
    I’ve checked permissions for almost all files and folders and it seems everything is OK.

    Could you please help
    Thank you in advance.

  23. RBD1987 says:

    HI, Pleaaaase help me i follow this tuto step by steeep but i have this!

    /usr/local/nagios/bin/nagios – /usr/local/nagios/etc/nagios.cfg
    -bash: /usr/local/nagios/bin/nagios: No such file or directory

    Thank you in advance.

  24. Gavin says:

    Hi, great tutorial! although I have encountered a small problem. Everything installed fine and I followed all of the steps up to number 7.

    Then I get this message:
    #/etc/init.d/nagios start

    starting nagios;No directory, logging in with Home=/

    any ideas?

  25. nagios_beingcrazy_user says:

    Cris have u solve your problem? I have the same problem.. ive no ideas about what to do. There are no details!

  26. Julian says:

    I am also stuck on this 🙁

  27. Fernando says:

    Thank you for your help .

  28. powershot says:

    Nagios will be configured to monitor a few aspects of your local . Thanks a lot! [Reply]. Brandon Perry says: June 20, 2010 at 7:13 pm .

  29. adarsh says:


    It really worked for me:)

    but am not able to install plugins, Showing 404 error please help !!!!

Leave a Reply

Your email address will not be published. Required fields are marked *