Creating the Cluster

Before any resources can be added to it, you need to create the cluster with YaST. This includes setting up the network over which the Heartbeats are sent and adding nodes to the cluster. Follow these steps:

1. Make sure that the Heartbeat software is installed on all nodes in the cluster.

2. From YaST on any node in the cluster, select System > High Availability. This opens the screen shown in Figure 29-7. On this screen, you need to make sure all nodes that you want to be in the cluster are added to the cluster. Don't add the node you are running this utility on; it is already there, but do add all the other nodes. Then click Next to proceed.

Figure 29-7. To start the cluster, run the Node Configuration utility on one node in the cluster, and from there add the names of all the nodes you want to be in the cluster.

3. On the Authentication Keys screen (see Figure 29-8), you specify how nodes authenticate to each other. If all nodes are in a secured data center, accept the default selection CRC (No Security). If you configure the cluster over an unsecure network, select either SHA1 or MD5, and enter a key that can be used for authentication. Then click Next to proceed.

Figure 29-8. For optimal performance on a secure network, choose CRC, which just adds a redundancy check on packets.

4. On the screen shown in Figure 29-9, you can specify how to communicate over the Heartbeat network. This is the network that nodes use to communicate to each other and see whether the other nodes are still there. For optimal fault tolerance, you should use a dedicated network for this. By default, broadcasts will be sent. If you don't want to bother nodes that are not in the cluster with your broadcasts, select Multicast instead. Next, enter an IP address used for the multicast packets. You can use any address between 224.0.0.0 and 239.255.255.255, as long as it isn't used by something else already. After specifying how you want to communicate, click Next to proceed.

Figure 29-9. In an ideal environment, you will have a separate network for the Heartbeat traffic.

5. You'll now see the final screen of the YaST module that helps you in configuring Heartbeat. In here, specify that you want to start the Heartbeat software every time your server boots. Then click Finish.

6. Now from the command line on the node where you configured Heartbeat, use the /usr/ lib/heartbeat/ha_propagate command. This will copy the configuration to all other nodes in the cluster if your node is able to resolve the host names of the other nodes. Notice that SSH must be available on all servers, because the configuration files are copied over an SSH connection.

7. On all other servers, use the command rcheartbeat start to start the Heartbeat service.

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