6.1. Clustered OLAT System Overview

Clustered System Overview

The clustered OLAT system is based on three layers :

Front-layer with apache and mod_jk as loadbanlacer see Section 6.3, “Configuration mod_jk as Loadbalancer”
Tomcat-layer with OLAT Web-application. Based on your number of concurrent clients, you will have a number of OLAT nodes. There is one special Node with single-services enabled. Single-services are course-logging, notifications etc. (see Section 6.4, “OLAT Cluster Properties”) This services could run only once in a OLAT cluster.
Backbone-service layer with database, shared filesystem, messaging-system (JMS) for cluster-node communication and Openfire chat server.

Each of the layer could be on different hosts. The services on a layer could be clustered vertical too e.g. each OLAT Node could be on an other machine.