Multi Site Open Monitoring Distribution Configuration

Configuring distributed monitoring using the Open Monitoring Distribution's Nagios - Check_MK - Livestatus - Multisite features.

Introduction

The Open Monitoring Distribution (OMD) provides an easy to install and configure Nagios system with Check_MK.  Check_MK uses the Livestatus broker module to efficiently process host and service checks.  Installation is described in this article.

Installing and configuring distributed Nagios Core monitoring -- using the Nagios Service Check Acceptor (NSCA) or mod_gearman is complicated and time-consuming.  OMD, however, includes menu-driven and web-interface configuration of Check_MK's Multisite feature -- distributed monitoring and centralized configuration.  This article explains how to configure Multisite distributed monitoring.

Configuring the Master Server

The Master Server is the one upon which all configurations are performed.  The Slave servers allow configuration, but the changes will be overwritten when the Master Server updates.

The Master Server must be configured as a local connection.  It requires a URL prefix of the host name, localhost or a valid IP address.  In this example, IP addresses are used and 127.0.0.1 selected as the URL prefix http://127.0.0.1/COU -- the site name is the directory.

Configuring Slave Servers

Enabling Livestatus

Slave servers require some additional work.  First, you must enable Livestatus from the server's menu configuration utility.  Stop the site with the command: "omd stop <site_name>."  The, start the configuration utility with the command "omd config <site_name."  Select "Distributed Monitoring."  Then, enable Livestatus as depicted below.

This creates and configures the file /opt/omd/sites/<site_name>/etc/xinetd.d/check_mk.  This xinetd service listens on TCP port 6557 and the file defines all parameters necessary for Master Server connections.

Creating Master to Slave Replication

Several items must be defined to enable replication:

1. The Livestatus IP address and TCP port 6557
2. The URL prefix http://<host_name or IP_address>/<site_name>
3. Slave replication
4. The Multisite URL http://<host_name or IP_address>/<site_name>/check_mk

Once configured and live, login to each Slave Server from the Master to enable replication.

Creating Hosts

Creating hosts is almost identical to creating them on single-server installations.  There is an additional -- and important -- field: the "Monitored on site" definition.  This provides a drop-down list of all configured Master and Slave Servers.

Organization is also important.  The author uses folders for each Master and Slave Server, each predefining the corresponding "Monitored on site" value.

The video below depicts the process of configuring OMD Distributed Monitoring.