Part I Installation, Setup and Upgrade #

SUSE® Linux Enterprise High Availability Extension is an integrated suite of open source clustering technologies that enables you to implement highly available physical and virtual Linux clusters, and to eliminate single points of failure. It ensures the high availability and manageability of critical resources including data, applications, and services. Thus, it helps you maintain business continuity, protect data integrity, and reduce unplanned downtime for your mission-critical Linux workloads.

It ships with essential monitoring, messaging, and cluster resource management functionality (supporting failover, failback, and migration (load balancing) of individually managed cluster resources).

This chapter introduces the main product features and benefits of the High Availability Extension. Inside you will find several example clusters and learn about the components making up a cluster. The last section provides an overview of the architecture, describing the individual architecture layers and processes within the cluster.

For explanations of some common terms used in the context of High Availability clusters, refer to Glossary.

The following section informs you about system requirements, and some prerequisites for SUSE® Linux Enterprise High Availability Extension. It also includes recommendations for cluster setup.

If you are setting up a High Availability cluster with SUSE® Linux Enterprise High Availability Extension for the first time, the easiest way is to start with a basic two-node cluster. You can also use the two-node cluster to run some tests. Afterward, you can add more nodes by cloning existing cluster nodes with AutoYaST. The cloned nodes will have the same packages installed and the same system configuration as the original ones.

If you want to upgrade an existing cluster that runs an older version of SUSE Linux Enterprise High Availability Extension, refer to chapter Chapter 5, Upgrading Your Cluster and Updating Software Packages.

The YaST cluster module allows you to set up a cluster manually (from scratch) or to modify options for an existing cluster.

However, if you prefer an automated approach for setting up a cluster, see the Démarrage rapide de l'installation et de la configuration. It describes how to install the needed packages and leads you to a basic two-node cluster, which is set up with the ha-cluster-bootstrap scripts.

You can also use a combination of both setup methods, for example: set up one node with YaST cluster and then use one of the bootstrap scripts to integrate more nodes (or vice versa).

This chapter covers two different scenarios: upgrading a cluster to another version of SUSE Linux Enterprise High Availability Extension (either a major release or a service pack) as opposed to updating individual packages on cluster nodes. See Section 5.2, “Upgrading your Cluster to the Latest Product Version” versus Section 5.3, “Updating Software Packages on Cluster Nodes”.

If you want to upgrade your cluster, check Section 5.2.1, “Supported Upgrade Paths for SLE HA and SLE HA Geo” and Section 5.2.2, “Required Preparations Before Upgrading” before starting to upgrade.