install nagios raspberry pi

How to Use Raspberry Pi to Monitor Network Devices? (Nagios)

If you have a Raspberry Pi running on your network 24/7, you can use it as a server for many things. I often have a monitoring solution on my network to keep an eye on all the important devices. I usually use Nagios for this, but could it run on Raspberry Pi?

It’s possible to install Nagios on a Raspberry Pi to monitor network devices. There are some basic requirements (Linux, Apache and PHP) and then it’s possible to use the same Nagios core and plugins as on any Linux server.

I’ve tried a few other solutions that I’ll mention quickly, but in my opinion, using Nagios from the source is the best way to monitor your network on Raspberry Pi. And of course, I’ll give you the step-by-step installation process.

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What is the best way to get Nagios on Pi?

When I first tried to install Nagios on my Raspberry Pi, I did a quick tour of the options.

I noticed different projects and ways to install it, so I took the time to see if there were better options than using the traditional method I’m used to on Linux servers (using a LAMP server + the Nagios sources).

Here are some of the options I’ve found:

Also: I've tested hundreds of Linux apps, here are the ones I recommend.

  • NagiosPi: It’s often easier to follow the instructions for a side project built and documented with the Raspberry Pi in mind. But this project seems to be dead, with no update since 2013, so I quickly moved on.
  • Using APT: Yes, Nagios is available through the Raspberry Pi OS package manager. But you often won’t get the latest version. Also, installing it with APT means you’ll install new versions without control (every time you do a system update). It’s a good option if you want to test it quickly, but not necessarily the best for production environments.
  • Installing NEMSLinux: It’s a preloaded image that you can flash to your SD card with Linux and Nagios, so it’s ready to go. The main problem was performance. I think too many things are enabled by default that are not suitable for the Raspberry Pi (especially old models).
  • Sources: Installing Nagios from source is not that complicated or time consuming. It’s a safe way to get the exact version you want and enable only what you need, so you don’t overload your Raspberry Pi with useless features.

Let me know in the community if you’ve found better solutions or had more success with some of the ones listed here, but for this tutorial, I’ll give you all the steps to install Nagios from source.

How to install Nagios on your Raspberry Pi

Here are the main steps to install Nagios on Raspberry Pi:

  1. Get a working Raspberry Pi OS on it.
  2. Install the prerequisites (Apache and PHP).
  3. Download the Nagios files from the official site.
  4. Extract and compile the sources for your system.

Let’s see how to do each step in more detail.

Install Raspberry Pi OS

The first thing you need is an operating system. I think Raspberry Pi OS Lite is perfect for this project, but use the desktop version if you are more comfortable with it.

Here are the first steps you need to complete before going further:

That’s it, system ready, we can move on.

Are you a bit lost in the Linux command line? Check this article first for the most important commands to remember and a free downloadable cheat sheet so you can have the commands at your fingertips.

Also: 15 Easy Projects for Raspberry Pi Beginners

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Downloads and prerequisites

Nagios is a web interface, so the first thing we need to do is install Apache and PHP:
sudo apt install apache2 libapache2-mod-php

Then we can download Nagios from the official website. There are two files we need to download:

  • Nagios Core: It’s the main part of the Nagios system.
  • Nagios Plugins: It’s like add-ons, including common checks for Nagios, so we don’t have to write scripts ourselves.

We need to download sources for them. Check their websites for the latest version:
Nagios Core downloads
Nagios Plugins downloads

If you have a desktop version, you can visit the download pages from the Raspberry Pi directly.
On a Lite system or via SSH, you can use the “wget” command to download the corresponding files:
cd ~
mkdir Downloads
cd Downloads
wget https://go.nagios.org/get-core/4-5-2/ -O Nagios-4.5.2.tar.gz
wget http://nagios-plugins.org/download/nagios-plugins-2.4.9.tar.gz

Now we are ready to move to the installation process.

Install Nagios on Raspberry Pi

Create Nagios user and group

We need to create a specific user for Nagios, and a group for Nagios and Apache users (nagcmd):
sudo useradd -m -s /bin/bash nagios
sudo groupadd nagcmd
sudo usermod -a -G nagcmd nagios
sudo usermod -a -G nagcmd www-data

Compile and install Nagios

Now we have to extract files from the archive, compile the sources and install Nagios on the Raspberry Pi:

Also: The 5 fastest web browsers for Raspberry Pi — tested and ranked!

  • Go to the “Downloads” directory:
    cd /home/$USER/Downloads
  • Extract files from the archive downloaded before:
    tar zxvf Nagios-4.5.2.tar.gz
    Don’t forget to change the version number if you downloaded a different one.
  • Start the configure step:
    cd nagios-4.5.2/
    ./configure --with-command-group=nagcmd
    If you get errors, it’s generally because some dependencies are missing. Try to find the corresponding package with APT.
    For example, during my test, I got the error “Cannot find ssl headers” which I fixed with:
    sudo apt install libssl-dev
    But it depends on what you already have on your system and the version you install, so you might get something different.
  • Once the configure step is complete, you can run this command:
    make all
    This could take a few minutes depending on your Raspberry Pi model and storage (way faster with an SSD or a Raspberry Pi 5).
  • You can now use sudo to run the installation:
    sudo make install
    sudo make install-init
    sudo make install-config
    sudo make install-commandmode

This is the end of the Nagios core installation.
We now need to configure the Apache part to allow access to the Nagios page.

Configure Apache for Nagios

  • Enable the CGI module for Apache:
    sudo a2enmod cgi
  • Copy the Apache configuration to the Apache folder:
    sudo cp sample-config/httpd.conf /etc/apache2/sites-enabled/nagios.conf
  • Create the first user for the web interface:
    sudo htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
    You will be prompted for a password.
  • Restart Apache:
    sudo service apache2 restart
  • Check if you have access to the web page:
    Go to http://<RASPBERRY IP>/nagios
    (check this tutorial if you don’t know how to find the current IP address).
    You should get something like this:

    The “Not running” message is normal, we’ll fix that now.

The Nagios installation is almost done, we just need to start the Nagios service.

Start the Nagios service

Nagios has a service running in the background to launch a check at a predefined frequency (every 5min for example). We need to start it to finish the installation.

Here is the command to start the service:
sudo service nagios start

Run this command to start Nagios automatically on boot:
sudo ln -s /etc/init.d/nagios /etc/rcS.d/S99nagios

If you refresh the web interface, you should now see “Daemon running with PID XXX”.
Everything is fine with Nagios, we want to add plugins now.

Install Nagios Plugins

We can now extract and install the Nagios plugins we downloaded earlier:

Also: Looking for a fun challenge? Start building your first Raspberry Pi robot!

  • Return to the Downloads folder:
    cd /home/$USER/Downloads
  • Extract files from the archive:
    tar zxvf nagios-plugins-2.4.9.tar.gz
  • Compile and install:
    cd nagios-plugins-2.4.9/
    ./configure --with-nagios-user=nagios --with-nagios-group=nagios
    make
    sudo make install

All plugins are now available in the /usr/local/nagios/libexec/ folder and ready to use in Nagios.

You may need to restart Nagios to apply changes:
sudo service nagios restart

How to configure Nagios to fit your needs?

Nagios vocabulary

Nagios uses jargon for all things related to configuration. So before you try to change anything, be sure you understand what I’m talking about.

Here are the main keywords:

  • Command: a command is a script from the Nagios plugins folder. We define it in Nagios to use later with parameters (ex: check_load is a command).
  • Service: a service is a check that applies to one or more computers, and uses a command to run a particular verification (ex: check if the load is above 10 on Raspberry Pi is a service).
  • Host: a host is a computer, a server, or anything with an IP address.
  • Hostgroup: you can define a host group, like “Raspberry Pi”, and apply the same services to all the hosts inside this group (e.g. all your Raspberry Pis).

We’ll now see how to configure these in the Nagios configuration file.
For the example below, I’ll monitor my Raspberry Pi Zero from the Raspberry Pi where Nagios is installed.

Prepare the host

Nagios uses mainly SNMP to connect to other hosts and get all the information. So we need to install SNMP on every new host before adding it to the configuration file.

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This is not mandatory, it depends on which services you’ll create for this host.
Anyway, I’ll show you how to do it, so you have a complete tutorial.

Also: I've tested hundreds of Linux apps, here are the ones I recommend.

In my case, I followed these steps on the Raspberry Pi Zero (not the same device as the Nagios server):

  • Connect to the host via SSH.
  • Install snmpd:
    sudo apt install snmpd
  • Go to the configuration folder:
    cd /etc/snmp
  • Remove (or backup) the default snmpd.conf file:
    sudo rm snmpd.conf
  • Create a new snmpd.conf file:
    sudo nano snmpd.conf
  • Paste these lines:
    com2sec readonly default RASPBERRYTIPS
    group MyROGroup v1 readonly
    group MyROGroup v2c readonly
    view all included .1 80
    access MyROGroup "" any noauth exact all none none
    sysName Pi Zero
    Replace RASPBERRYTIPS with the community you want to use.
    Replace sysName with your host name or description.
    There are many options available in snmpd.conf, but for this test we don’t need more than that.
  • Save and exit the configuration file.
  • Restart the service:
    sudo service snmpd restart

We can now add this host in Nagios.

Add a host

  • Get back to the Raspberry Pi hosting Nagios.
  • Go to this folder:
    cd /usr/local/nagios/etc/objects
  • Create a new file for your host, like pizero.cfg:
    sudo nano pizero.cfg
  • Paste these lines into it:
    define host {
    use linux-server  ; Host group to use
    host_name Pi Zero  ; Name of this host
    alias pizero  ; Alias
    address 192.168.1.18  ; IP Address
    }
    This is a basic host definition, with the host name, alias and IP address.
    We also add it to the Linux servers host group to inherit group-defined services if you add some later
  • Save and exit (CTRL+O, CTRL+X).
  • Now we need to tell Nagios that we added a new file.
    Add this line in /usr/local/nagios/etc/nagios.cfg (just under localhost.cfg will be perfect):
    cfg_file=/usr/local/nagios/etc/objects/pizero.cfg
  • Restart Nagios to apply changes:
    sudo service nagios restart
  • Go back to the Nagios web interface, in the Hosts menu.
    You should have a new line like this:
    nagios add host

Nagios already monitors the ping response for our new host, but we want more.
So we need to add a service inside, but we have to define the command to use first.

Add a command

Previously in this tutorial, you downloaded and installed Nagios plugins. Nagios plugins provide many commands to check the local host, but not so much for remote hosts.

You can also download many other commands on this website (specifically look for SNMP plugins).

For this example, I’ll monitor the time synchronization between my two Raspberry Pi.

To add a command in Nagios, follow these steps:

Also: No screen? No problem! Here's how to setup a Pi without one.

  • Go to the Nagios plugins folders:
    cd /usr/local/nagios/libexec
  • Run the command without parameters:
    ./check_ntp
  • Note the help message and parameters you need to pass.
    In my case, I got this error message:
    Usage: check_ntp -H <host> [-w <warn>] [-c <crit>] [-j <warn>] [-k <crit>] [-4|-6] [-v verbose]
    So, I know I have to specify the host IP in the -H argument.
    And maybe a warning and critical threshold with -w and -c
    Other options don’t seem relevant to me
  • Open the commands configuration file:
    sudo nano /usr/local/nagios/etc/objects/commands.cfg
  • Check if your command is already inside and if not, you have to add it like this:
    define command {
    command_name check_ntp
    command_line $USER1$/check_ntp -H $HOSTADDRESS$ -w $ARG1$ -c $ARG2$
    }
  • Save, exit and restart Nagios:
    sudo service nagios restart
  • Check that your command is now available in Nagios.
    • Go to the web interface.
    • Click on “Configuration” in the left menu.
    • Choose “Commands” in the list and click “Continue”.
    • You should now see “check-ntp” in the list (or any command you add).

The command is now ready to be used for your host, but we need to create a new service to apply it.

Add a service

To create a new service, follow these steps:

  • Open your host configuration file:
    sudo nano /usr/local/nagios/etc/objects/pizero.cfg
    Adapt the filename to what you have created before.
  • Paste these lines:
    define service {
    use local-service  ; Name of service template to use
    host_name Pi Zero
    service_description Time synchronization
    check_command check-ntp!1!5
    }
    Don’t forget to adapt these lines to your previous configuration.
    On the check_command line, we define all arguments, separated by exclamation points.
  • Save and exit.
  • Check your configuration:
    sudo /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
    This can be useful to know if you have configuration errors before restarting Nagios.
    In my case, I wrote check_ntp instead of check-ntp.
  • Restart Nagios:
    sudo service nagios restart

Now in the status detail from your host you should see the new service.

nagios service detail

If you understood how to create a host, a command and a service, you are now ready to do anything in Nagios.

Feel free to download new plugins on Internet, or even code your plugins (it’s nothing more than a basic script to check something).

Video

https://www.youtube.com/watch?v=lehq-UE-400
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Related questions

Can I manage Nagios configuration directly from the web interface?

Unfortunately, no. Nagios doesn’t provide a configuration tool in the core version. But there are several configuration tools you can install. I often use Thruk, I haven’t tried it on Raspberry Pi yet, but you can download it here if you want.

Can I monitor Windows hosts with Nagios?

Yes, you can monitor anything on your network. SNMP is also available for Windows and most network devices (routers, switches, home automation devices, …). Since you can create your check commands, anything is possible.

Also: Probably one of the best Raspberry Pi workstations (review)

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Want to chat with other Raspberry Pi enthusiasts? Join the community, share your current projects and ask for help directly in the forums.

Conclusion

That’s it, you know how to install and configure a Nagios server on your Raspberry Pi to monitor your network or anything you want. With this tutorial, you get the latest Nagios version, with no excessive load average (currently 0.00 on my Pi ^^).

Once Nagios is installed, it’s not really different from any Nagios server on Linux.
So feel free to check Linux tutorials for advanced configuration.

And if you want to create easy-to-read graphs with the data generated in Nagios, take a look at how to install Grafana on your Raspberry Pi.

Update: I recently tested Zabbix on Raspberry Pi, which looks a bit more intuitive to get started. For a small network, it’s probably a suitable alternative (I have less experience with it, but it seems great).

Whenever you’re ready, here are other ways I can help you:

The RaspberryTips Community: If you want to hang out with me and other Raspberry Pi fans, you can join the community. I share exclusive tutorials and behind-the-scenes content there. Premium members can also visit the website without ads.

Master your Raspberry Pi in 30 days: If you are looking for the best tips to become an expert on Raspberry Pi, this book is for you. Learn useful Linux skills and practice multiple projects with step-by-step guides.

The Raspberry Pi Bootcamp: Understand everything about the Raspberry Pi, stop searching for help all the time, and finally enjoy completing your projects.

Master Python on Raspberry Pi: Create, understand, and improve any Python script for your Raspberry Pi. Learn the essentials step-by-step without losing time understanding useless concepts.

You can also find all my recommendations for tools and hardware on this page.

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43 Comments

  1. Getting the following error while opening http:///nagios

    Nagios Core

    <frame src="” name=”main” frameborder=”0″ style=””>


    Nagios Core

    http://www.nagios.org
    Copyright © 2010- Nagios Core Development Team and Community Contributors.
    Copyright © 1999-2010 Ethan Galstad

    Note: These pages require a browser which supports frames

  2. Hi dabance,

    This message doesn’t help
    Can you paste the exact error message? Or a screenshot maybe?

    Thanks

  3. Thank you for the excellent guide.
    Sadly, I’m having trouble installing the nagios plugins because a whole bunch of pre-requisites are missing.
    From the nagios install webpage, there are a bunch of yum packages (which the raspberry pi doesn’t have):

    https://support.nagios.com/kb/article/nagios-core-installing-nagios-core-from-source-96.html#Debian

    eg.
    yum install -y gcc glibc glibc-common make gettext automake autoconf wget openssl-devel net-snmp net-snmp-utils
    yum install -y perl-Net-SNMP

    Looks like I need to find some equivalents for apt-get…

  4. I just needed to install gettext:
    apt-get install gettext
    … splendid! Thanks again 🙂

  5. Hi,

    When attempting to do the following step:

    sudo cp sample-config/httpd.conf /etc/apache2/sites-enabled/nagios.conf

    I get the following error:

    cp: cannot stat ‘sample-config/httpd.conf’: No such file or directory

    Which step creates this file? Or should it have been on my system already? I am on a Raspberry Pi 3 B+

  6. Hello Thank you for the guide,
    I am having trouble runnning Nagios.

    I don’t have installed plug-in because before that, when I am accessing to my Nagios web page.
    It says : Nagios Core Not running,
    I check the status of nagios service and nothing special appears :

    ● nagios4.service – LSB: nagios host/service/network monitoring and management system
    Loaded: loaded (/etc/init.d/nagios4; generated)
    Active: active (running) since Mon 2019-07-29 19:15:26 CEST; 13min ago
    Docs: man:systemd-sysv-generator(8)
    Process: 2388 ExecStart=/etc/init.d/nagios4 start (code=exited, status=0/SUCCESS)
    Tasks: 8 (limit: 2200)
    Memory: 3.1M
    CGroup: /system.slice/nagios4.service
    ├─2418 /usr/sbin/nagios4 -d /etc/nagios4/nagios.cfg
    ├─2419 /usr/sbin/nagios4 –worker /var/lib/nagios4/rw/nagios.qh
    ├─2420 /usr/sbin/nagios4 –worker /var/lib/nagios4/rw/nagios.qh
    ├─2421 /usr/sbin/nagios4 –worker /var/lib/nagios4/rw/nagios.qh
    ├─2422 /usr/sbin/nagios4 –worker /var/lib/nagios4/rw/nagios.qh
    ├─2423 /usr/sbin/nagios4 –worker /var/lib/nagios4/rw/nagios.qh
    ├─2424 /usr/sbin/nagios4 –worker /var/lib/nagios4/rw/nagios.qh
    └─2428 /usr/sbin/nagios4 -d /etc/nagios4/nagios.cfg

    Thanks for the help

    1. Hello,

      Do you have an error when you start the service?

      Or can you check the log file?
      I think it’s in /var/log/syslog

  7. Hello,

    Thanks for the fast reply,
    I have find this in the log file regarding Nagios :
    Jul 29 21:19:09 raspberrypi nagios4[4410]: Starting nagios4 monitoring daemon: nagios4.
    Jul 29 21:19:09 raspberrypi nagios4: Nagios 4.3.4 starting… (PID=4440)
    Jul 29 21:19:09 raspberrypi nagios4: Local time is Mon Jul 29 21:19:09 CEST 2019
    Jul 29 21:19:09 raspberrypi nagios4: LOG VERSION: 2.0
    Jul 29 21:19:09 raspberrypi nagios4: qh: Socket ‘/var/lib/nagios4/rw/nagios.qh’ successfully initialized
    Jul 29 21:19:09 raspberrypi nagios4: qh: core query handler registered
    Jul 29 21:19:09 raspberrypi nagios4: nerd: Channel hostchecks registered successfully
    Jul 29 21:19:09 raspberrypi nagios4: nerd: Channel servicechecks registered successfully
    Jul 29 21:19:09 raspberrypi nagios4: nerd: Channel opathchecks registered successfully
    Jul 29 21:19:09 raspberrypi nagios4: nerd: Fully initialized and ready to rock!
    Jul 29 21:19:09 raspberrypi nagios4: wproc: Successfully registered manager as @wproc with query handler
    Jul 29 21:19:09 raspberrypi nagios4: wproc: Registry request: name=Core Worker 4442;pid=4442
    Jul 29 21:19:09 raspberrypi nagios4: wproc: Registry request: name=Core Worker 4443;pid=4443
    Jul 29 21:19:09 raspberrypi systemd[1]: Started LSB: nagios host/service/network monitoring and management system.
    Jul 29 21:19:09 raspberrypi nagios4: wproc: Registry request: name=Core Worker 4446;pid=4446
    Jul 29 21:19:09 raspberrypi nagios4: wproc: Registry request: name=Core Worker 4441;pid=4441
    Jul 29 21:19:09 raspberrypi nagios4: wproc: Registry request: name=Core Worker 4444;pid=4444
    Jul 29 21:19:09 raspberrypi nagios4: wproc: Registry request: name=Core Worker 4445;pid=4445
    Jul 29 21:19:09 raspberrypi nagios4: Successfully launched command file worker with pid 4450

    I also tried this :
    sudo nagios4 restart
    output :
    Nagios Core 4.3.4
    Copyright (c) 2009-present Nagios Core Development Team and Community Contributors
    Copyright (c) 1999-2009 Ethan Galstad
    Last Modified: 2017-08-24
    License: GPL

    Website: https://www.nagios.org
    Error: Cannot open main configuration file ‘/usr/local/nagios/etc/objects/restart

    But I think that’s normal, there is no “restart” file in this folder

    1. Hi,

      There is no error in your log file, so I don’t know what the problem could be

      Good commands to manage the nagios service are:

      • sudo service nagios start
      • sudo service nagios stop
      • sudo service nagios restart

      You can also try sudo journalctl -xe to see the last errors

  9. Hello, I followed you tutorial and it is really good. Had some problems but figured it out. Can you help me with installing Nagios network analyzer on raspbian? Nagios server is already up and working. Can I manually put NAA or not?

      1. Hello again, NNA is not working on Raspbian.. Tried few different releases and none work. It is not officially supported. Really don’t know how to get this done. Maybe any other way to get nagios analyze some network data? Wrote alot of stuff about Nagios and this project and don’t want to abandon it but thinking about shifting to wireshark

  11. This was an incredible walkthrough! I did have one issue which I figured out. I was attempting to install Nagios Core 4.4.5 and “sudo ln -s /etc/init.d/nagios /etc/rcS.d/S99nagios” didn’t work for me because there was nothing in init.d at all! I googled it a bit and figured out that I needed to instead run “sudo systemctl enable nagios.service” and now my device successfully loads the nagios service at startup. Thanks so much.

  12. Hi, I got to the section to add a host to monitor and both the localhost and my host that I was adding are showing as down.

    I get this error status when I dig a little further:
    (No output on stdout) stderr: execvp(/usr/local/nagios/libexec/check_ping, …) failed. errno is 2: No such file or directory

    Any ideas?

    1. Hello,

      Make sure that the script you try to use exist in this folder (check_ping in libexec)
      But I think it’s one of the default scripts

  13. Used an old Pi2 that I had set up as a LAMP server using Ubuntu 18.04. I had to add sudo make install-daemoninit during install to get the service to start at bootup. Other than that, instructions worked great. Thank you Patrick!

  14. Hi, I am having an issue with adding the host. Everything is fine until I type “sudo service nagios restart” as it throws up the following error:

    “Job for nagios.service failed because the control process exited with error code.
    See “systemctl status nagios.service” and “journalctl -xe” for details.”

    Once I’ve typed “systemctl status nagios.service”

    It shows the following:

    ● nagios.service – Nagios Core 4.4.5
    Loaded: loaded (/lib/systemd/system/nagios.service; enabled; vendor preset: enabled)
    Active: failed (Result: exit-code) since Tue 2020-03-31 16:40:19 BST; 55s ago
    Docs: https://www.nagios.org/documentation
    Process: 26901 ExecStartPre=/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg (code=exited, status=1/FAILURE)
    Process: 26902 ExecStopPost=/bin/rm -f /usr/local/nagios/var/rw/nagios.cmd (code=exited, status=0/SUCCESS)

    Mar 31 16:40:19 raspberrypi nagios[26901]: ***> One or more problems was encountered while processing the config files…
    Mar 31 16:40:19 raspberrypi nagios[26901]: Check your configuration file(s) to ensure that they contain valid
    Mar 31 16:40:19 raspberrypi nagios[26901]: directives and data definitions. If you are upgrading from a previous
    Mar 31 16:40:19 raspberrypi nagios[26901]: version of Nagios, you should be aware that some variables/definitions
    Mar 31 16:40:19 raspberrypi nagios[26901]: may have been removed or modified in this version. Make sure to read
    Mar 31 16:40:19 raspberrypi nagios[26901]: the HTML documentation regarding the config files, as well as the
    Mar 31 16:40:19 raspberrypi nagios[26901]: ‘Whats New’ section to find out what has changed.
    Mar 31 16:40:19 raspberrypi systemd[1]: nagios.service: Control process exited, code=exited, status=1/FAILURE
    Mar 31 16:40:19 raspberrypi systemd[1]: nagios.service: Failed with result ‘exit-code’.
    Mar 31 16:40:19 raspberrypi systemd[1]: Failed to start Nagios Core 4.4.5.

    1. Hi Philip,

      Yes, it’s common as soon as there is a little issue with your configuration

      You can get more details with:
      sudo /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

  16. Hi, this all worked great until i tried to add a host. No errors at all came up, but still only the local host showing
    Could it be because the Pi Zero is connected wireless through mesh access point and the Pi 3 running Nagios is wired?
    I’ve tries restarting both services but still not being registered
    Thanks

    1. I’m having the same issue. I followed the walkthrough and added hosts but I only get localhost. Not sure what I’m doing wrong.

      1. I’ve actually resolved this issue. The problem was that I had renamed the template/group named from linux_server to something else and Nagios was getting confused. Not sure how to add new group named…

        I am having a different issue however – when I reboot by Pi, Nagios will not startup automatically.

  19. New to Linux. During the Apache Configuration I get “htpasswd: cannot create file /usr/local/nagios/etc/htpasswd.users” at the command:

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

    I don’t think I’ve missed anything?

  20. Hi I have a problem in the configuration of the apache in this step
    sudo cp sample-config/httpd.conf /etc/apache2/sites-enabled/nagios.conf
    after that it appears:
    cp: cannot start ‘sample-config/httpd.conf’ :no such file or directory

    1. HI,

      Do you have this error on starting Apache? or when you try to copy the file?
      Are your sure to be in the correct folder? (does the file exists?)

      1. Using this tutorial (with a few modifications) I’ve successfully installed Nagios 4.4.6 on PiZero with DietPi (since I don’t have the “w” version I’ve used a USB network card for LAN) connection.
        Install and configure DietPi – DietPi instruction on official website
        Connect to Pi using SSH (root user will be used during install so there is no need for “sudo” if connecting with other user you must add sudo or use “sudo su”) :
        [code]
        apt update && apt upgrade
        apt install apache2 libapache2-mod-php gettext build-essential
        mkdir DW_Nagios && cd DW_Nagios
        wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.6.tar.gz && wget https://nagios-plugins.org/download/nagios-plugins-2.3.3.tar.gz
        useradd -m -s /bin/bash nagios && groupadd nagcmd && sudo usermod -a -G nagcmd nagios && sudo usermod -a -G nagcmd www-data
        tar zxvf nagios-4.4.6.tar.gz
        cd nagios-4.4.6/
        ./configure –with-command-group=nagcmd
        make all
        make install
        make install-init
        make install-config
        make install-commandmode
        a2enmod cgi
        cp sample-config/httpd.conf /etc/apache2/sites-enabled/nagios.conf
        htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin
        service apache2 restart
        service nagios start
        ln -s /etc/init.d/nagios /etc/rcS.d/S99nagios
        cd ..
        tar zxvf nagios-plugins-2.3.3.tar.gz
        cd nagios-plugins-2.3.3
        ./configure –with-nagios-user=nagios –with-nagios-group=nagios
        make
        make install
        [/code]

        After that had some issue with nagios service, the following resolve it:
        [code]
        Create this nagios.service file

        # vi /etc/systemd/system/nagios.service
        [Unit]
        Description=Nagios
        BindTo=network.target

        [Install]
        WantedBy=multi-user.target

        [Service]
        User=nagios
        Group=nagios
        Type=simple
        ExecStart=/usr/local/nagios/bin/nagios /usr/local/nagios/etc/nagios.cfg
        # systemctl enable /etc/systemd/system/nagios.service
        # systemctl start nagios
        # systemctl status nagios
        After that you need to restart the Nagios Service.

        # /etc/init.d/nagios restart
        That’s it you should now be able to access Nagios WEBUI.
        [/code]

        Everything worked without issues (usually i had to search for some dependency that was missing from DietPi due to it being such a slimmed down OS).
        Thanks for the article and all the useful comments.
        P.S. Although I had issues posting this comment, getting message : ERROR: Sorry, human verification failed. but no chaptcha was displayed

      2. Wow, dunno what happened to the formatting of my previous message.
        Anyway, if someone is using DietPy and wonder why mail notifications are not working is because you need to install some packages :
        – apt install mailutils sendmail

        After installing them you can run a simple test from terminal using :
        mail -s “This is the subject” email@domain.com <<< 'This is the message'

        Now i still had a small issue since the binary were installed in /usr/bin and nagios was looking for them in /bin, there are two solutions :
        – modify the commands in commands.cfg file
        – make a sim-link using : ln -s /usr/bin/mail /bin/

  22. Hi, when attempting to Check if I have access to Nagios using http:///nagios), it says “No such file or directory”. Do I need to run this on a web browser using the rapsberry pi or in the command line terminal?

  23. Hello Patrick,

    This is a great tutorial did you do a youtube video for this yet? If not you should, this is a great tutorial for nagios on a Raspberry Pi. I believe you covered everythign except how to configure notifications. I have been trying to find an excellent tutorial for that and I cannot. Do you have any experience with notifications? If so please share with us. I actually have nagios working in a Docker Container and it works great just trying to figure out 2 things before I release the tutorial on my website. Thank you so much for your hard work I do appreciate it so much.

    1. Hi Michael,

      Yes, there is a YouTube video (one of my first so not the best one, but it should work).
      I’ve added it in this article.

      For the notifications, I’m just using the default email notifications, and I also have some of them configured with Pushbullet (to get them on my phone).
      It should work easily once the system email configured.

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