Nagios and Centreon
Configuring Nagios with Centreon
What is Centreon?
Centreon is essentially a monitoring platform that uses Nagios at its core. Centreon allows an administrator to easily configure Alerts based on thresholds, generate email Alerts, Add systems to be monitored quickly without the need of configuring complicated configuration files. Centreon acts as a dashboard (front-end) to Nagios. In the example below we will use Centreon as part of the Fully Automated Nagios (FAN) installation). If you have not already downloaded and installed "Fully Automated Nagios", then click on the installation guide link Fully Automated Nagios
Accessing Centreon from your web browser
Assuming you have installed Fully Automated Nagios, and your installation server is up and running, then all that is needed is to type the hostname or the IP address of your server into a modern browser such as Mozilla Firefox or Chrome. Once the address has been entered, you will initially be asked to enter a userid and password. By default these have been set to:
UserID: nagiosadmin with a Password: nagiosadmin
Once the correct credentials have been entered, you are initially taken to the FAN home screen as below:
Centreon can now be accessed by clicking on the link in the left hand frame under the heading "Direct Links". Once clicked, you will again be asked to enter a valid userid and password combination. The default userid and password for Centreon is the same as the above userid/password combination:
UserID: nagiosadmin with a Password: nagiosadmin
Once entered you will be taken to the "Centreon" home screen as per screen-shot below:
From this screen you can now click on various Administration/Configuration options. As a first task, you will probably want to disable the default password of "nagiosadmin". This can be done easily clicking on the option Configuration >> Users
From this screen you can now simply click on the account you want to disable and then add a new account.
Centreon - Modifying Users Accounts
From this screen you can now see any accounts that are available to you. Here you can add/delete accounts, enable/disable accounts very easily. All you need to do is place a tick in the column to the left of the userid and click on the "More Actions" pull down menu. Here you can "Duplicate", "Delete", "Enable" or "Disable" an account.
If you want to change the passwords, simply select the account you wish to work with by clicking on the "userid" under the "Name" column. Next click on the "Centreon Authentication" tab. Here you will see various parameters that can be changed.
Adding Hosts to be Monitored
Adding a Host to be monitored by Nagios is a simple task using "Centreon". To access the host configuration menu, simply click on the "Configuration" tab followed then by the "Hosts" tab. (Configuration >> Hosts).
Initially you will see a view similar to the one below. The only server currently being monitored is the "Centreon-Server".
To add a new host, simply click on the "add" link under the "Name" column. You will now be presented with a screen where you can enter details such as "hostname", "ip address", "check period", commands to be run (what to monitor). In the example below, I have added two hosts to be monitored by a simple "Ping" (host_alive check). Many other options exist to monitor CPU, Load, Memory, Disk, process presence, Users and services. These are available from a simple pull down menu.
Export new configurations to Nagios
Once we have added our hosts and selected what to monitor, we now need to export these configurations to Nagios. This is done by clicking on the tab "Monitoring Engines". Once selected, you will see a list of actions that can be selected. In this example, all four actions have been selected. Once this is done click "Export" to apply the new configuration files and restart Nagios. Progress will be displayed of the export along with any accompanying messages.
Nagios Host Detail Overview Screen
Now go back to the Main home screen and click the Nagios Link. Next click on the "Host Detail" tab. You should now see an overview of your servers that are being monitored:
Official Sites - Documentation
Fully Automated Nagios is an excellent tool for the configuration/monitoring of small to large infrastructures. This is either done from a standalone server as per our example above or can be carried out with a distributed installation.
Details of a distributed installation can be found at the main Nagios site: FAN Distributed installation
A good way to try out FAN is to install FAN into Oracle's VirtualBox or VMWare virtualization software. This will allow you to play around with the settings/configurations.
Further documentation can be found at the official Fully Automated Nagios site:FAN Documentation
It is always worth reading the Nagios documentation as it will give you a better understanding of how FAN works under the covers.
Documentation for Centreon can be found at Centreon
Documentation for Nagvis can be found at Nagvis