NOTE: CentOS Enterprise Linux is built from the Red Hat Enterprise Linux source code. Other than logo and name changes CentOS Enterprise Linux is compatible with the equivalent Red Hat version. This document applies equally to both Red Hat and CentOS Enterprise Linux.
Before describing the steps to configure the cluster, the
hierarchical structure of cluster members and resources needs to be
considered. Cluster members and resources can be thought of in
terms of a hierarchical structure, as shown in Figure 3-5.
Figure 3-5. Cluster Configuration Structure
The cluster is comprised of cluster nodes. The cluster nodes are
connected to a fencing device. Nodes can be separated by failover
domains to a cluster service. The services are comprised of managed
resources, such as NFS exports, IP addresses, and shared GFS
partitions. The structure is ultimately reflected in the /etc/cluster/cluster.conf XML structure.
The steps to configure the cluster software consist of the
Run the Cluster Configuration Tool on
one cluster member.
Click on the Cluster property and click
the Edit Cluster Properties button. Enter
a name for the cluster in the Name field.
The name should be descriptive enough to distinguish it from other
clusters and systems on your network (for example, nfs_cluster or httpd_cluster). The Config
Version field should be set to 1
by default and is automatically incremented each time you save your
To add a cluster node, click the property, then click the Add a
Cluster Node button. Enter a cluster name that you can remember
(such as the hostname assigned to the node, if any). Then click the
amount of Quorum Votes you want to assign
to the system.
Click on the Fence Device property and
click the Add a Fence Device button to
configure a fence device. Choose the device from the supported list
in the drop-down menu. Each device has different configurations
that you must enter (such as Name,
IP Address, Login
name and Password, if applicable.
Click the triangle next to Managed
Resources, and click the Failover
Domains property to set up one or more failover domains, if
needed. Failover domains restrict the members on which a cluster
service can run or restrict the order of members followed when a
cluster service fails over from one failover domain member to
another. Refer to Section
3.6 Configuring a Failover Domain for details.
Configure the Resources to be managed by
the cluster, specifying any IP addresses, file systems, NFS
exports, or user scripts to be managed by the cluster. Refer to
Section 3.7 Adding Cluster
Resources for more information.
Configure a failover domain for the cluster service.
Additionally, configure the cluster service using the available
cluster resources, or create private resources used exclusively for
the that service. Refer to Section
3.8 Adding a Cluster Service to the Cluster for more
Save cluster configuration changes by selecting => . When you
save the cluster configuration, the command service rgmanager reload command is executed to
cause the cluster software to load the changed configuration
Quit the application by selecting
Running the Cluster Configuration
Tool for the first time causes the cluster configuration file
/etc/cluster/cluster.conf to be created
Copy the /etc/cluster/cluster.conf
file to the other nodes using the scp