Active-active Alfresco cluster with MySQL Galera and GlusterFS
Alfresco is a popular collaboration tool available on the open-source market. It is Java based, and has a content repository, web application framework and web content management system. For critical large-scale implementations that require 24*7 uptime, a multi-node cluster would be appropriate. Since Alfresco depends on external components such as the database and the filesystem, clustering the Alfresco instances only would not be enough.
In this post, we are going to show you how to deploy an active-active Alfresco cluster with MySQL Galera Cluster (database), GlusterFS (filesystem) and HAproxy with Keepalived (load balancer) to achieve redundancy of all the required system components.
Please note that clustering of Alfresco instances is only available in the Alfresco Enterprise. Hazelcast is used to provide multicast messaging between the web-tier nodes. This blog will be using the community edition, and note that e.g. site/user dashboard layout changes on one Alfresco node are not replicated to the other nodes since Hazelcast is only enabled in the enterprise edition. However, the content repository works fine in the community edition as the content files are on the same GlusterFS partition and the content metadata is replicated via Galera.
Architecture
We will have a three-node Galera cluster co-located with Alfresco. Another two nodes, fs1 and fs2 will be used as a replicated file storage system for Alfresco content using GlusterFS. These two nodes will also have HAproxy and Keepalived for high availability load-balancing. ClusterControl will be hosted on fs2 to monitor Galera nodes. We will be using Alfresco version 4.2 (Community edition) and all hosts are running on Debian 7.2 Wheezy 64bit. All commands shown below are executed in root environment.
