Installation guide

Fig u re 2.1. Web Server Clu st er Service Example

Clients access the HA service through the IP address 10.10.10.201, enabling interaction with the web

server application, httpd-content. The httpd-content application uses the gfs2-content-webserver file

system. If node B were to fail, the content-webserver HA service would fail over to node D. If node D

were not available or also failed, the service would fail over to node A. Failover would occur with

minimal service interruption to the cluster clients. For example, in an HTTP service, certain state

information may be lost (like session data). The HA service would be accessible from another cluster

node via the same IP address as it was before failover.

Note

For more information about HA services and failover domains, refer to the High Availability Add-

On Overview. For information about configuring failover domains, refer to Chapter 3,

Configuring Red Hat High Availability Add-On With Conga(using C o n g a) or Chapter 7, Configuring

Red Hat High Availability Manually (using command line utilities).

An HA service is a group of cluster resources configured into a coherent entity that provides

Red Hat Ent erprise Linux 6 Clust er Administ rat ion