Installation guide

Note

The cluster types summarized in the preceding text reflect basic configurations; your needs

might require a combination of the clusters described.

Additionally, the Red Hat Enterprise Linux High Availability Add-On contains support for

configuring and managing high availability servers only. It does not support high-performance

clusters.

1.2. High Availabilit y Add-On Int roduct ion

The High Availability Add-On is an integrated set of software components that can be deployed in a

variety of configurations to suit your needs for performance, high availability, load balancing,

scalability, file sharing, and economy.

The High Availability Add-On consists of the following major components:

Cluster infrastructure — Provides fundamental functions for nodes to work together as a cluster:

configuration-file management, membership management, lock management, and fencing.

High availability Service Management — Provides failover of services from one cluster node to

another in case a node becomes inoperative.

Cluster administration tools — Configuration and management tools for setting up, configuring,

and managing a the High Availability Add-On. The tools are for use with the Cluster Infrastructure

components, the high availability and Service Management components, and storage.

Note

Only single site clusters are fully supported at this time. Clusters spread across multiple

physical locations are not formally supported. For more details and to discuss multi-site

clusters, please speak to your Red Hat sales or support representative.

You can supplement the High Availability Add-On with the following components:

Red Hat GFS2 (Global File System 2) — Part of the Resilient Storage Add-On, this provides a

cluster file system for use with the High Availability Add-On. GFS2 allows multiple nodes to share

storage at a block level as if the storage were connected locally to each cluster node. GFS2

cluster file system requires a cluster infrastructure.

Cluster Logical Volume Manager (CLVM) — Part of the Resilient Storage Add-On, this provides

volume management of cluster storage. CLVM support also requires cluster infrastructure.

Load Balancer Add-On — Routing software that provides IP-Load-balancing. the Load Balancer

Add-On runs in a pair of redundant virtual servers that distributes client requests evenly to real

servers that are behind the virtual servers.

1.3. Clust er Infrast ruct ure

The High Availability Add-On cluster infrastructure provides the basic functions for a group of

computers (called nodes or members) to work together as a cluster. Once a cluster is formed using the

Red Hat Ent erprise Linux 6 High Availabilit y Ad d- O n O verview