Appendix B. Configuration Example Using pcs Commands This appendix provides a step-by-step procedure for configuring a two-node Red Hat Enterprise Linux High Availability Add-On cluster, using the pcs command, in Red Hat Enterprise Linux release 6.6 and later. It also describes how to configure an Apache HTTP server in this cluster. Configuring the cluster provided in this chapter requires that your system include the following components: 2 nodes, which will be used to create the cluster. In this example, the nodes used are z1.example.com and z2.example.com . Network switches for the private network, required for communication among the cluster nodes and other cluster hardware such as network power switches and Fibre Channel switches. A power fencing device for each node of the cluster. This example uses two ports of the APC power switch with a host name of zapc.example.com . B.1. Initial System Setup This section describes the initial setup of the system that you will use to create the cluster. B.1.1. Installing the Cluster Software Use the following procedure to install the cluster software. Ensure that pcs , pacemaker , cman , and fence-agents are installed. After installation, to prevent corosync from starting without cman , execute the following commands on all nodes in the cluster. B.1.2. Creating and Starting the Cluster This section provides the procedure for creating the initial cluster, on which you will configure the cluster resources. In order to use pcs to configure the cluster and communicate among the nodes, you must set a password on each node for the user ID hacluster , which is the pcs administration account. It is recommended that the password for user hacluster be the same on each node. Before the cluster can be configured, the pcsd daemon must be started. This daemon works with the pcs command to manage configuration across the nodes in the cluster. On each node in the cluster, execute the following commands to start the pcsd service and to enable pcsd at system start. Authenticate the pcs user hacluster for each node in the cluster on the node from which you will be running pcs . The following command authenticates user hacluster on z1.example.com for both of the nodes in the example two-node cluster, z1.example.com and z2.example.com . Execute the following command from z1.example.com to create the two-node cluster mycluster that consists of nodes z1.example.com and z2.example.com . This will propagate the cluster configuration files to both nodes in the cluster. This command includes the --start option, which will start the cluster services on both nodes in the cluster. Optionally, you can enable the cluster services to run on each node in the cluster when the node is booted. Note For your particular environment, you may choose to leave the cluster services disabled by skipping this step. This allows you to ensure that if a node goes down, any issues with your cluster or your resources are resolved before the node rejoins the cluster. If you leave the cluster services disabled, you will need to manually start the services when you reboot a node by executing the pcs cluster start command on that node. You can display the current status of the cluster with the pcs cluster status command. Because there may be a slight delay before the cluster is up and running when you start the cluster services with the --start option of the pcs cluster setup command, you should ensure that the cluster is up and running before performing any subsequent actions on the cluster and its configuration.

Commands:
install -y pcs pacemaker cman fence-agents
chkconfig corosync off chkconfig cman off
passwd hacluster Changing password for user hacluster. New password: Retype new password: passwd: all authentication tokens updated successfully.
service pcsd start chkconfig pcsd on
root@z1 ~]# pcs cluster auth z1.example.com z2.example.com Username: hacluster Password: z1.example.com: Authorized z2.example.com: Authorized
pcs cluster setup --start --name my_cluster z1.example.com z2.example.com z1.example.com: Succeeded z1.example.com: Starting Cluster z2.example.com: Succeeded z2.example.com: Starting Cluster
pcs cluster enable --all
pcs cluster status Cluster Status: Last updated: Thu Jul 25 13:01:26 2013 Last change: Thu Jul 25 13:04:45 2013 via crmd on z2.example.com Stack: corosync Current DC: z2.example.com (2) - partition with quorum Version: 1.1.10-5.el7-9abe687 2 Nodes configured 0 Resources configured