Procedure 3.2. Defining the Communication Channels

1. In the YaST cluster module, switch to the Communication Channels category.

2. Define the Bind Network Address, the Multicast Address and the Multicast Port to use for all cluster nodes.

3. If you want to define a second channel:

   1. Activate Redundant Channel.

   2. Define the Bind Network Address, the Multicast Address and the Multicast Port for the redundant channel.

   3. Select the rrp_mode you want to use. To disable the RRP, select None. For more information about the modes, click Help.

      When using RRP, the primary ring (the first channel you have configured) gets the ringnumber 0, the second ring (redundant channel) the ringnumber 1 in /etc/corosync/corosync.conf.

4. Activate Auto Generate Node ID to automatically generate a unique ID for every cluster node.

5. If you only wanted to modify the communication channels for an existing cluster, click Finish to write the configuration to /etc/corosync/corosync.conf and to close the YaST cluster module. YaST then automatically also adjusts the firewall settings and opens the UDP port used for multicast.

6. For further cluster configuration, click proceed with Procedure 3.3, “Enabling Secure Authentication”.

Procedure 3.3. Enabling Secure Authentication

1. In the YaST cluster module, switch to the Security category.

2. Activate Enabling Security Auth.

3. For a newly created cluster, click Generate Auth Key File. This creates an authentication key that is written to /etc/corosync/authkey.

4. If you only want to modify the authentication settings, click Finish to write the configuration to /etc/corosync/corosync.conf and to close the YaST cluster module.

5. For further cluster configuration, proceed with Section 3.2.3, “Transferring the Configuration to All Nodes”.

Procedure 3.4. Configuring Csync2 with YaST

1. In the YaST cluster module, switch to the Csync2 category.

2. To specify the synchronization group, click Add in the Sync Host group and enter the local hostnames of all nodes in your cluster. For each node, you must use exactly the strings that are returned by the hostname command.

3. Click Generate Pre-Shared-Keys to create a key file for the synchronization group. The key file is written to /etc/csync2/key_hagroup. After it has been created, it must be copied manually to all members of the cluster.

4. To populate the Sync File list with the files that usually need to be synchronized among all nodes, click Add Suggested Files.

5. If you want to Edit, Add or Remove files from the list of files to be synchronized use the respective buttons. You must enter the absolute pathname for each file.

6. Activate Csync2 by clicking Turn Csync2 On. This will start Csync2 automatically at boot time.

7. If all options are set according to your wishes, click Finish to close the YaST cluster module. YaST then writes the Csync2 configuration to /etc/csync2/csync2.cfg.

Procedure 3.5. Synchronizing the Configuration Files with Csync2

To successfully synchronize the files with Csync2, make sure that the following prerequisites are met:

1. Start the file synchronization by executing the following command on one of the nodes:

   csync2 -xv

   This will synchronize all the files once. If all files can be synchronized successfully, Csync2 will finish with no errors.

   If one or several files that are to be synchronized have been modified also on other nodes (not only on the current one), Csync2 will report a conflict. You will get an output similar to the one below:

   While syncing file /etc/corosync/corosync.conf:
   ERROR from peer hex-14: File is also marked dirty here!
   Finished with 1 errors.

2. If you are sure that the file version on the current node is the “best” one, you can resolve the conflict by forcing this file and resynchronizing:

   csync2 -f /etc/corosync/corosync.conf
   csync2 -x

Procedure 3.6. Starting or Stopping Services

1. In the YaST cluster module, switch to the Service category.

2. To start OpenAIS each time this cluster node is booted, select the respective option in the Booting group.

3. If you want to use the Pacemaker GUI for configuring, managing and monitoring cluster resources, activate Start mgmtd as Well. This daemon is needed for the GUI.

4. To start or stop OpenAIS immediately, click the respective button.

5. Click Finish to close the YaST cluster module.