1 About High Availability Clustering

This chapter describes how to set up and configure the Pacemaker and Corosync technologies to create a high availability (HA) cluster that delivers continuous access to services that are running across multiple nodes.

High availability services in Oracle Linux consist of several open source packages and components, including the following:

Pacemaker

Pacemaker is an open source high availability cluster resource manager that's responsible for managing the life cycle of software that's deployed on a cluster. Pacemaker provides high availability services by detecting and recovering from node and resource-level failures by using the API that's provided by the cluster engine Corosync.

Corosync

Corosync, which is included in the Pacemaker package, is an open source cluster engine that includes an API to implement several high availability features. Corosync provides an availability manager that can restart a process when it fails, a configuration and statistics database, and a quorum system that can notify applications when quorum is achieved or lost.

Pacemaker and Corosync Configuration System (pcs)

The Pacemaker and Corosync Configuration System (pcs) includes the pcs command line interface to manage a cluster and its resources. The pcsd daemon runs as a service on each node in the cluster, making it possible to synchronize configuration changes across all the nodes in the cluster.

The pcs package also includes a web user interface for managing clusters.

You can download Corosync, Pacemaker, their dependencies, and related packages, from the Unbreakable Linux Network (ULN) at https://linux.oracle.com or the Oracle Linux yum server at https://yum.oracle.com.

Oracle provides support for Corosync and Pacemaker that's used for an active-passive 2-node (1:1) cluster configuration on Oracle Linux 10. Note that support for clustering services doesn't imply support for Oracle products that are clustered by using these services.

Oracle also provides Oracle Clusterware for high availability clustering with Oracle Database. You can find more information at https://www.oracle.com/database/technologies/rac/clusterware.html.