⁠Chapter 13. Nagios Installation

13.1. Install the Nagios Service
13.1.1. Install the NRPE Addon
13.2. Configure Nagios
13.2.1. Configure HTTPD for Nagios
13.2.2. Configure Nagios to Monitor OpenStack Services
13.2.3. Configure NRPE
13.2.4. Create Host Definitions
13.2.5. Create Service Definitions for Remote Services
13.2.6. Verify the Nagios Configuration

⁠13.1. Install the Nagios Service

The Nagios monitoring system can be used to provide monitoring and alerts for the OpenStack network and infrastructure. The following installation procedure installs:
nagios
Nagios program that monitors hosts and services on the network, and which can send email or page alerts when a problem arises and when a problem is resolved.
nagios-devel
Includes files which can be used by Nagios-related applications.
nagios-plugins*
Nagios plugins for Nagios-related applications (including ping and nrpe).
gd
Graphics Library, for dynamically creating images
gd-devel
Development libraries for Graphics Library (gd)
php
HTML-embedded scripting language, used by Nagios for the web interface.
gcc, glibc and glibc-common
GNU compiler collection, together with standard programming libraries and binaries (including locale support).
openssl
OpenSSL toolkit, which provides support for secure communication between machines.
Install the required packages as the root user, using the yum command: 
# yum install nagios nagios-devel nagios-plugins* gd gd-devel php gcc glibc glibc-common openssl

Note

If any of the packages are not immediately available (for example, gd-devel or gcc), you might have to enable the optional Red Hat channel using subscription-manager: 
# subscription-manager repos --enable rhel-6-server-optional-rpms

⁠13.1.1. Install the NRPE Addon

NRPE (Nagios Remote Plugin Executor) plugins are compiled executables or scripts that are used to check the status of a host's service, and report back to the Nagios service. If the OpenStack cloud is distributed across machines, the NPRE addon can be used to run access plugin information on those remote machines.
NRPE and the Nagios plugins must be installed on each remote machine to be monitored. On the remote machine, and as the root user, execute the following: 
# yum install -y nrpe nagios-plugins* openssl
After the installation, you can view all available plugins in the /usr/lib64/nagios/plugins directory (depending on the machine, they may be in /usr/lib/nagios/plugins).

Note

SSH can also be used to access remote Nagios plugins. However, this can result in too high a CPU load on both the Nagios host and remote machine, and is not recommended.