Procedure 2.1. Modifying /etc/hosts with YaST¶

1. On one SLES 10 server, open YaST, and in left column, select Network Services+Hostnames.

2. In the Host Configuration window, click Add and fill in the necessary information in the pop-up window for one other server in the cluster.

   This information includes the IP address, hostname (for example node2.novell.com), and host alias (for example node2) of the other server.

   Use node names for host aliases. You can find node names by executing uname -n at a command prompt on each server.

3. Click OK, and then repeat Step 2 to add the other nodes in the cluster to the /etc/hosts file on this server.

4. Repeat Step 1 through Step 3 on each server in your Heartbeat cluster.

5. To check if hostname resolution is functioning properly, ping the node name (host alias) you specified in Step 2 .

Procedure 2.2. Configuring the Heartbeat Servers for Time Synchronization¶

Time synchronization will not start unless the date and time on the cluster servers is already close. To manually set the date and time on cluster servers, use the date command at the command line of each cluster server to view, and if necessary change, the date and time for that server.

To configure the nodes in the cluster to use the time server as their time source proceed as follows:

1. On a cluster server, start YaST, click Network Services, then click NTP Client.

2. Choose to have the NTP daemon start during boot and then enter the IP address of the time server you configured.

3. Click Finish and reboot this server to ensure the service starts correctly.

4. Repeat Step 1 through Step 3 on the other non-time server nodes in the cluster.

5. Reboot all cluster nodes. After rebooting the nodes, time should be synchronized properly.

6. To check if time synchronization is functioning properly, run the ntpq -p command on each cluster node. Running the ntpq -p command on a non-time server node will display the server that is being used as the time source.

1. Start YaST and select Miscellaneous+High Availability or enter yast2 heartbeat to start the YaST Heartbeat module. It lets you create a new cluster or add new nodes to an existing cluster.

2. On the Node Configuration screen, add a node to the cluster by specifying the node name of the node you want to add, then click Add. Repeat this process for each node you want to add to the cluster, then click Next.

   Figure 2.1. Node Configuration¶
   
   

   You can find node names for servers by entering uname -n on each node.

   The installation program will not let you add this node, because the node name of this server is already automatically added to the cluster.

   If after adding a node to the cluster, you need to specify a different node name for that node, double-click the node you want to edit, change the node name, then click Edit.

3. On the Authentication Keys screen, specify the authentication method the cluster will use for communication between cluster nodes, and if necessary an Authentication Key (password). Then click Next.

   Figure 2.2. Authentication Keys¶
   
   

   Both the MD5 and SHA1 methods require a shared secret, which is used to protect and authenticate messages. The CRC method does not perform message authentication, and only protects against corruption, not against attacks.

   The SHA1 method is recommended, because it provides the strongest authentication scheme available. The authentication key (password) you specify will be used on all nodes in the cluster.

   When running this installation program on the other cluster nodes, you should choose the same authentication method for all nodes.

4. On the Media Configuration screen, specify the method Heartbeat will use for internal communication between cluster nodes. This configuration is written to /etc/ha.d/ha.cf.

   Figure 2.3. Media Configuration¶
   
   

   This provides a way for cluster nodes to signal that they are alive to other nodes in the cluster. For proper redundancy, you should specify at least two Heartbeat media if possible. Choose at least one Heartbeat medium, and if possible, more than one:

   • If you choose Broadcast, select one of the available network devices in the Device list.

   • For Multicast, choose a network Device, Multicast Group to join (class D multicast address 224.0.0.0 - 239.255.255.255) and the TTL value (1-255).

   UDP Port sets the UDP port that is used for the broadcast media. Leave this set to the default value (694) unless you are running multiple Heartbeat clusters on the same network segment, in which case you need to run each cluster on a different port number.

   	UDP Port Settings
   Note that the UDP port setting only apply to broadcast media, not to the other media you may use. When editing UDP ports manually in /etc/ha.d/ha.cf, the udpport entry must precede the bcast entry it belongs to, otherwise Heartbeat will ignore the port setting.

   After specifying a Heartbeat medium, click Add to add that medium type to Heartbeat and proceed with Next.

5. On the Start-up Configuration screen, choose whether you want to start the Heartbeat software on this cluster server each time it is booted.

   Figure 2.4. Startup Configuration¶
   
   

   If you select Off, you must start Heartbeat manually each time this cluster server is booted. You can start the Heartbeat server manually using the rcheartbeat start command.

   To start the Heartbeat server immediately, select On - Start Heartbeat Server Now and when Booting.

   To start Heartbeat on the other servers in the cluster when they are booted, enter chkconfig heartbeat on at the server console of each of those servers. You can also enter chkconfig heartbeat off at the server console to have Heartbeat not start automatically when the server is rebooted.

6. To configure Heartbeat on the other nodes in the cluster run /usr/lib/heartbeat/ha_propagate on the heartbeat node you just configured. On 64-bit systems, the command ha_propagate is located below /usr/lib64/heartbeat/.

   This will copy the Heartbeat configuration to the other nodes in the cluster. You will be prompted to enter the root user password for each cluster node.

7. Run rcheartbeat start to start heartbeat on each of the nodes where the configuration has been copied.

Procedure 2.3. Configuring STONITH as a Cluster Resource¶

1. Start the HA Management Client and log in to the cluster as described in Section 4.1, “Graphical HA Management Client”.

2. To generally enable the use of STONITH, select the linux-ha entry in the left pane and click the Configurations tab on the right.

3. Activate the STONITH Enabled check box.

4. From the menu, select Resources+Add New Item or click the + button.

5. Choose Native as the item type.

6. Specify the Resource ID (name) for the STONITH resource.

7. In the Type section of the window, scroll down and select the type of STONITH device that corresponds to your network power switch.

8. (Conditional) After selecting a STONITH resource type, a line for that resource type might be added to the Parameters section of the screen. If a line is added, click the line once and then click the line again under the Value heading to open a field where you can add the needed value.

   Some STONITH options require you to add parameter values in the parameters section of the page. For example, you may be required to add host names (server names) for each cluster node in your cluster. You can find the hostname for each server using the uname -n command on the server. You can add multiple hostnames in the provided field using a comma or a space to separate the names.

9. Select the Clone check box. This allows the resource to simultaneously run on multiple cluster nodes.

10. In the clone_node_max field, enter the number of instances of STONITH that will run on a given node. This value should normally be set to 1.

11. In the clone_max field, enter the number of nodes in the cluster that will run the STONITH service. Be mindful of the number of concurrent connections your STONITH device supports.

12. Enter the Clone or Master/Slave ID.

13. Click Add to add the STONITH resource to the cluster. It now appears below the Resources entry in the left pane.

14. Select the resource in the left pane and click Resource+Start to start the STONITH resource.