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Discover a comprehensive guide on installing NagiosQL on CentOS 7. Follow our step-by-step instructions for prerequisites, installation, and configuration to get Nagios Server up and running. #centlinux #linux #nagios

What is NagiosSQL?

Nagios Core is an free and open source Network, Server and Application monitoring software. A drawback of Nagios Core is that it lacks a configuration tool, therefore we have to edit configurations files using a text editor. Manually editing configuration files is always a headache and highly prone to typo static errors.

NagiosQL is a web based configurator for Nagios Core. It completely integrates with Nagios Core and makes configuration management much easier. We have configured another Nagios configurator: Lilac Reloaded in our previous article.

In this article, we will install NagiosQL on CentOS 7 based Nagios Core server. We are assuming that, you already have basic understanding of Nagios and related technologies. Otherwise, it is recommended that, you should read Learning Nagios – Third Edition (PAID LINK) by Packt Publishing to enhance your knowledge in this area.

Nagios Server Specification

We are using the same CentOS 7 virtual machine, on which we have configured Nagios Core.

  • Hostname –
  • IP Address –
  • Operating System – CentOS 7.6
  • Nagios Version – Nagios Core 4.4
  • NagiosQL Version – 3.4

Install MariaDB on CentOS 7

NagiosQL requires MariaDB or MySQL database for creating its repository. Therefore, we are installing the available MariaDB server from CentOS 7 yum repository.

# yum install -y mariadb-server

Start and enable MariaDB service.

# systemctl enable mariadb.service
Created symlink from /etc/systemd/system/ to /usr/lib/systemd/system/mariadb.service.
# systemctl start mariadb.service

Configure MariaDB database instance.

# mysql_secure_installation


In order to log into MariaDB to secure it, we'll need the current
password for the root user.  If you've just installed MariaDB, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.

Enter current password for root (enter for none):
OK, successfully used password, moving on...

Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.

Set root password? [Y/n] Y
New password:
Re-enter new password:
Password updated successfully!
Reloading privilege tables..
 ... Success!

By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] Y
 ... Success!

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] Y
 ... Success!

By default, MariaDB comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] Y
 - Dropping test database...
 ... Success!
 - Removing privileges on test database...
 ... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] Y
 ... Success!

Cleaning up...

All done!  If you've completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!

Install Apache on CentOS 7

Since, we are installing on the same server, on which we are running Nagios Core, then there is no need to install Apache HTTP server, because it was already installed during Nagios Core configurations.

Install PHP on CentOS 7

Since, we are installing on the same server, on which we have configured Nagios Core. Therefore, we have already installed PHP 5.4 on it during Nagios Core configurations. But NagiosQL required PHP 5.5 or above, therefore, we have to upgrade PHP from 5.4 to 5.5.

PHP 5.5 is available through various third party yum repositories. Therefore, we are installing webtatic yum repository.

But first, install EPEL (Extra Packages for Enterprise Linux) as a prerequisite for webtatic yum repository.

# yum install -y epel-release

Download and install Webtatic yum repository RPM from Webtatic Website according to your Linux version.

# rpm -Uvh
warning: /var/tmp/rpm-tmp.OjmyAU: Header V4 RSA/SHA1 Signature, key ID 62e74ca5: NOKEY
Preparing...                          ################################# [100%]
Updating / installing...
   1:webtatic-release-7-3             ################################# [100%]

Build yum cache for newly added yum repositories.

# yum makecache fast
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
epel/x86_64/metalink                                     | 7.7 kB     00:00
 * base:
 * epel:
 * extras:
 * updates:
 * webtatic:
base                                                     | 3.6 kB     00:00
extras                                                   | 3.4 kB     00:00
updates                                                  | 3.4 kB     00:00
webtatic                                                 | 3.6 kB     00:00
(1/2): webtatic/x86_64/group_gz                            |  448 B   00:00
(2/2): webtatic/x86_64/primary_db                          | 144 kB   00:02
Metadata Cache Created

Remove current version of PHP.

# yum remove -y php-common php php-gd php-cli

Install PHP 5.5 from webtatic yum repository.

# yum install -y php55w-common php55w php55w-gd php55w-cli php55w-mysql php55w-devel php55w-pear

Install libssh2-devel package required by PHP.

# yum install -y libssh2-devel

Install ssh2 extension for PHP from PECL (PHP Extension Community Library).

# pecl channel-update
Updating channel ""
Update of Channel "" succeeded
# pecl install ssh2
Build process completed successfully
Installing '/usr/lib64/php/modules/'
install ok: channel://
configuration option "php_ini" is not set to php.ini location
You should add "" to php.ini

Add following directives in /etc/php.ini.

# echo "date.timezone='Asia/Karachi'" >> /etc/php.ini
# echo "" >> /etc/php.ini

Restart Apache service.

# systemctl restart httpd

We have installed all the NagiosQL prerequisite packages on our CentOS 7 server.

Install NagiosQL on CentOS 7

NagiosQL is available at Nagios Exchange and SourceForge. While you can also download NagiosQL Documentation from SourceForge website.

Download NagiosQL latest version and copy it in home directory of root user.

# tar xjf nagiosql-3.4.0.tar.bz2 -C /var/www/html/

# mv /var/www/html/nagiosql-3.4.0/ /var/www/html/nagiosql

Reapply SELinux security context for /var/www/html/nagiosql/ directory.

# restorecon -Rv /var/www/html/nagiosql/

Create a directory for NagiosQL to place Nagios Core configuration files.

# mkdir /usr/local/nagios/etc/nagiosql
# chown apache:apache /usr/local/nagios/etc/nagiosql/

Give write permission to all users on config directory for creating configuration files.

# chmod o+w /var/www/html/nagiosql/config

Browse URL to run NagiosQL installation wizard.

NagiosQL Installation Wizard
NagiosQL Installation Wizard

Since, we are running NagiosQL installation wizard for the first time and there isn’t any settings.php file exists in config folder, therefore the wizard is giving us the following warning

“Settings file not found or not readable (config/settings.php). Upgrade not available!”

It is save to ignore it.


NagiosSQL Installation - Checking Requirements
NagiosSQL Installation – Checking Requirements

NagiosQL installation wizard is checking for requirments and will give warnings, if a prerequisite is missing.

If you have followed the steps above correctly, then it won’t give you any warning.

Click on Next.

NagiosSQL Installation - Setup
NagiosSQL Installation – Setup

Define the settings according to the above screenshot.

Click on Next.

NagiosQL Installation - Finishing Setup
NagiosQL Installation – Finishing Setup

Click on Next.

If everything goes fine, then you will reach at the NagiosQL login page.

NagiosQL Login
NagiosQL Login

Login as admin user.

NagiosQL Dashboard
NagiosQL Dashboard

NagiosQL Post Installation Configurations

NagiosQL has been installed, we can now delete install directory to prevent anyone to run installation wizard again.

# rm -rf /var/www/html/nagiosql/nagiosql-3.4.0/install/

We have successfully generated settings.php file. Therefore, revoke write permissions from other users for security.

# chmod o-w /var/www/html/nagiosql/config

Import Nagios Core configuration

NagiosQL is installed with zero configurations, therefore, we have to import our existing Nagios Core configurations.

Go to Administration > Config Targets.

NagiosQL - Configure Domain Administration 1
NagiosQL – Configure Domain Administration 1

Click on Modify under Function column.

NagiosQL - Configure Domain Administration 2
NagiosQL – Configure Domain Administration 2

Adjust directory paths according to you environment and click on Save.

Go to Tools > Data Import.

Select all import files and click on Import.

NagiosQL - Configuration Import
NagiosQL – Configuration Import

Go to Supervision tab and you may observe that there are now some active groups has been imported.

NagiosQL - Define Services
NagiosQL – Define Services

File status is missed because we haven’t save our files yet. Therefore, Click on Write all config files.

You may observe that the file status is now up-to-date.

Repeat the process for other targets/configurations like hosts, commands, templates, etc to save them in NagiosQL configure directory.

Finally, we have to edit nagios.cfg file to remove current cfg_dir directives and add our new configuration directory actively managed by NagiosQL. This can be achieved by following two commands.

# sed -i 's/^cfg/#cfg/' /usr/local/nagios/etc/nagios.cfg
# echo "cfg_dir=/usr/local/nagios/etc/nagiosql/" >> /usr/local/nagios/etc/nagios.cfg

Restart nagios.service to check is there any configuration errors.

# systemctl restart nagios.service

If you have performed above steps correctly, then there should be no error.

Now, Nagios Core is using configurations from NagiosQL configuration directory.

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Final Thoughts

I hope this guide on installing NagiosQL on CentOS 7 has been helpful for you. By following these steps, you can successfully set up and configure NagiosQL for effective monitoring of your IT infrastructure. If you encounter any issues or need professional support, I’m here to assist you. Check out my Fiverr gig for expert help with NagiosQL installations, configurations, and more: Red hat Certified Engineer (RHCE)

Feel free to reach out for personalized solutions to ensure your NagiosQL setup is done right and efficiently!

30 thoughts on “How to install NagiosQL on CentOS 7”
  1. Hello Ahmer,

    Afeter following all the above steps, I found this problem when restarting Nagios:
    Error: Failed to locate check_period '24×7' for host 'hplj2605dn'!
    Error: Could not register host (config file '/usr/local/nagios/etc/nagiosql/hosts/hplj2605dn.cfg', starting on line 16)
    Do you have any ideas about this error?
    Thanks beforehand

  2. Hi,
    Make sure that you have imported timeperiods.cfg in nagiosql.
    Also, this host file (hplj2605dn.cfg) is related to a printer. and you can safely remove it, if do not want to configure a printer.

  3. Hello,
    I get this error at the end

    [root@nagios01 etc]# systemctl restart nagios.service
    Job for nagios.service failed because the control process exited with error code. See "systemctl status nagios.service" and "journa lctl -xe" for details.

    [root@nagios01 etc]# systemctl status nagios.service
    ● nagios.service – Nagios Core 4.4.3
    Loaded: loaded (/usr/lib/systemd/system/nagios.service; enabled; vendor preset: disabled)
    Active: failed (Result: exit-code) since Wed 2019-04-17 14:56:32 PDT; 7min ago
    Process: 24140 ExecStopPost=/usr/bin/rm -f /usr/local/nagios/var/rw/nagios.cmd (code=exited, status=0/SUCCESS)
    Process: 24137 ExecStop=/usr/bin/kill -s TERM ${MAINPID} (code=exited, status=0/SUCCESS)
    Process: 24142 ExecStartPre=/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg (code=exited, status=1/FAILURE)
    Main PID: 7011 (code=exited, status=0/SUCCESS)

    Apr 17 14:56:32 nagios01.cci.local nagios[24142]: Check your configuration file(s) to ensure that they contain valid
    Apr 17 14:56:32 nagios01.cci.local nagios[24142]: directives and data definitions. If you are upgrading from a previous
    Apr 17 14:56:32 nagios01.cci.local nagios[24142]: version of Nagios, you should be aware that some variables/definitions
    Apr 17 14:56:32 nagios01.cci.local nagios[24142]: may have been removed or modified in this version. Make sure to read
    Apr 17 14:56:32 nagios01.cci.local nagios[24142]: the HTML documentation regarding the config files, as well as the
    Apr 17 14:56:32 nagios01.cci.local nagios[24142]: 'Whats New' section to find out what has changed.
    Apr 17 14:56:32 nagios01.cci.local systemd[1]: nagios.service: control process exited, code=exited status=1
    Apr 17 14:56:32 nagios01.cci.local systemd[1]: Failed to start Nagios Core 4.4.3.
    Apr 17 14:56:32 nagios01.cci.local systemd[1]: Unit nagios.service entered failed state.
    Apr 17 14:56:32 nagios01.cci.local systemd[1]: nagios.service failed.
    [root@nagios01 etc]#

  4. Hi,
    It looks like, you may have some syntax errors in Nagios configuration files.
    Use following command to find these errors.

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

    Rectify all errors and then start nagios service.

  5. Hi, I follow your procedure, and in he last step, an error occurs:

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

    And Nagios don't start anymore.

    The web interface it is working, but this is the message "Unable to get process status"

    And the log is:

    [05-24-2019 15:09:36] Successfully shutdown… (PID=9027)
    Program End[05-24-2019 15:09:36] Caught SIGTERM, shutting down…
    Program End[05-24-2019 15:09:36] Caught SIGTERM, shutting down…

    What could be the problem?

    Thanks in advance.

    Best regards.

  6. Hi,
    Usually, this kind of problem is encountered due to typo-static error in config files.
    Therefore, you should check you config files using following command.

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

    and rectify any possible error.

  7. I am encountering an issue with not being able to use two Nagios Control Buttons:
    Check Configuration Files – error: Cannot find the Nagios binary or no execute permissions!
    Restart Nagios: Nagios daemon is not running, cannot send restart command!

    Everything else is working between Nagiosql and Nagios.

  8. Hi, I have a problem – I cant get nagiosql to populate nagios core. I have added a host in nagiosql but when i checked nagios core it is not showing up. Any assistance will be highly appreciated.

  9. Ahmer,
    Thank you for your time. I found the answer (RTFM….) and it was Max. Check attempts *.
    I misunderstood it in the beginning and set it to 999999 thinking it would continually check.
    Now i see it would check but only be in a soft state so no alerts.
    I will check out the FB page.


  10. Hi, very helpful, was able to go about on some errors, but when I do Write All config – the file will go out-of-date. actually ever since still out of date, but it is working though. I was able to add host and services

  11. I just followed the guide but hit a roadblock at the end of the database install

    Create new NagiosQL database
    You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '1', '0', '1', '1', '1', '1', '', NOW())' at line 1

    Database server connection (privileged user) passed (mysqli)
    Database server version 5.5.68-MariaDB
    Database server support supported
    Delete existing NagiosQL database done (db_nagiosql_v35)
    Creating new database done (db_nagiosql_v35)
    Installing NagiosQL database tables done
    Create NagiosQL database user done (Only added rights to existing user: nagiosql_user)
    Set initial NagiosQL Administrator failed

    anyone know what the issue here is and how to correct it?

  12. Hi, It looks like NagiosQL isn't supporting your database version.

    This article is based on CentOS 7 and default MariaDB provided with it. Therefore, you can try your configurations on CentOS 7.

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