Chapter 3. Cluster Creation and Administration

This chapter describes how to perform basic cluster administration with Pacemaker, including creating the cluster, managing the cluster components, and displaying cluster status.

3.1. Cluster Creation

To create a running cluster, perform the following steps:
  1. Start the pcsd on each node in the cluster.
  2. Authenticate the nodes that will constitute the cluster.
  3. Configure and sync the cluster nodes.
  4. Start cluster services on the cluster nodes.
The following sections described the commands that you use to perform these steps.

3.1.1. Starting the pcsd daemon

The following commands start the pcsd service and enable pcsd at system start. These commands should be run on each node in the cluster. 
# service pcsd start
# chkconfig pcsd on

3.1.2. Authenticating the Cluster Nodes

The following command authenticates pcs to the pcs daemon on the nodes in the cluster.
  • The user name for the pcs administrator must be hacluster on every node. It is recommended that the password for user hacluster be the same on each node.
  • If you do not specify user name or password, the system will prompt you for those parameters for each node when you execute the command.
  • If you do not specify any nodes, this command will authenticate pcs on the nodes that are specified with a pcs cluster setup command, if you have previously executed that command. 
pcs cluster auth [node] [...] [-u username] [-p password]
For example, the following command authenticates user hacluster on z1.example.com for both of the nodes in the cluster that consist of z1.example.com and z2.example.com. This command prompts for the password for user hacluster on the cluster nodes. 
root@z1 ~]# pcs cluster auth z1.example.com z2.example.com
Username: hacluster
Password:
z1.example.com: Authorized
z2.example.com: Authorized
Authorization tokens are stored in the file ~/.pcs/tokens (or /var/lib/pcsd/tokens).

3.1.3. Configuring and Starting the Cluster Nodes

The following command configures the cluster configuration file and syncs the configuration to the specified nodes.
  • If you specify the --start option, the command will also start the cluster services on the specified nodes. If necessary, you can also start the cluster services with a separate pcs cluster start command.
    When you create a cluster with the pcs cluster setup --start command or when you start cluster services with the pcs cluster start command, there may be a slight delay before the cluster is up and running. Before performing any subsequent actions on the cluster and its configuration, it is recommended that you use the pcs cluster status command to be sure that the cluster is up and running.
  • If you specify the --local option, the command will perform changes on the local node only. 
pcs cluster setup [--start] [--local] --name cluster_ name node1 [node2] [...]
The following command starts cluster services on the specified node or nodes.
  • If you specify the --all option, the command starts cluster services on all nodes.
  • If you do not specify any nodes, cluster services are started on the local node only. 
pcs cluster start [--all] [node] [...]

3.1.4. Enabling and Disabling Cluster Services

Use the following command to configure the cluster services to run on startup on the specified node or nodes.
  • If you specify the --all option, the command enables cluster services on all nodes.
  • If you do not specify any nodes, cluster services are enabled on the local node only. 
pcs cluster enable [--all] [node] [...]
Use the following command to configure the cluster services not to run on startup on the specified node or nodes.
  • If you specify the --all option, the command disables cluster services on all nodes.
  • If you do not specify any nodes, cluster services are disabled on the local node only. 
pcs cluster disable [--all] [node] [...]
You can verify whether cluster services are enabled by running the pcs status command on a running cluster. At the bottom of the output of this command, you should see that pacemaker is enabled, which ensures that the cluster starts on reboot. All other services should be disabled. 
# pcs status
...
Daemon Status:
  cman: active/disabled
  corosync: active/disabled
  pacemaker: active/enabled
  pcsd: active/disabled
If the cluster is not running, you can verify whether cluster services are enabled by running the following chkconfig command. If 2, 3, 4, and 5 are on, the cluster is enabled. 
# chkconfig --list pacemaker
pacemaker      	0:off	1:off	2:on	3:on	4:on	5:on	6:off