Reconfiguring a Cluster

(Serviceguard 11.16 only, requires root login to the cluster.) First halt the cluster. Select it on the tree or map. From the Actions menu, select Administering Serviceguard, then Halt Cluster.

When halted, select the cluster in the map or tree. From the Actions menu, select Configuring Serviceguard. When the Configuring Cluster window opens, click the Parameters tab. Enter the new number. Click Apply. Close the configuration window. (After refresh, check the cluster’s Properties to see the change.)

The cluster must be halted.

Use the cmgetconf command to obtain a current copy of the cluster's existing configuration. Example:

# cmgetconf -C clconfig.ascii 

Edit the clconfig.ascii file to include the desired value for MAX_CONFIGURED_PACKAGES. Then use the cmcheckconf command to verify the new configuration. Time can be significantly reduced if you use the -k or -K options with cmcheckconf. Using -k or -K option with the cmcheckconf command, can significantly reduce the response time.

Use the cmapplyconf command to apply the changes to the configuration and send the new configuration file to all cluster nodes. Time can be significantly reduced if you use the -k or -K options with cmapplyconf.

Select the cluster on the tree or map. Choose Configuring from the Actions menu. You need root permission on the cluster. On the Nodes tab, under Available nodes, highlight the node you want to add, and click Add. Then click Apply. After Refresh, check the cluster’s Properties to confirm the change.

Use the following procedure to add a node with HP-UX commands. For this example, nodes ftsys8 and ftsys9 are already configured in a running cluster named cluster1, and you are adding node ftsys10.

Use cmrunnode to start the new node, and, if desired, set the AUTOSTART_CMCLD parameter to 1 in the /etc/rc.config.d/cmcluster file to enable the new node to join the cluster automatically each time it reboots.

	NOTE: If you add a node to a running cluster that uses CVM disk groups, the disk groups will be available for import when the node joins the cluster.

The node must be halted. If it is not, select it and choose Administering Serviceguard from the Actions menu. Choose Delete Node.

Select the cluster on the tree or map. Choose Configuring Serviceguard from the Actions menu. (You need root permission on the cluster.) On the Nodes tab, under Available nodes, highlight the node to remove, and click Delete. Then click Apply. After Refresh, check the cluster’s Properties to confirm the change.

If the node you wish to delete is unreachable (disconnected from the LAN, for example), you can delete the node only if there are no packages which specify the unreachable node. If there are packages that depend on the unreachable node, halt the cluster or use Serviceguard commands as described in the next section.

Use the following procedure to delete a node with HP-UX commands. For this example, nodes ftsys8, ftsys9 and ftsys10 are already configured in a running cluster named cluster1, and you are deleting node ftsys10.

	NOTE: If you are attempting to remove an unreachable node that has many packages dependent on it, especially if the dependent packages use a large number of EMS resources, you may see the following message: The configuration change is too large to process while the cluster is running. Split the configuration change into multiple requests or halt the cluster. In this situation, you must halt the cluster to remove the node.

Select the cluster on the tree or map. Choose Configuring Serviceguard from the Actions menu. (You need root permission on the cluster.) On the Logical Volumes tab highlight the node to add or remove, and click Add or Delete. Then click Apply. After Refresh, check the cluster’s Properties to confirm the change.

You cannot change the cluster lock volume group or physical volume configuration while the cluster is running.

	NOTE: If you are removing a volume group from the cluster configuration, make sure that you also modify or delete any package control script that activates and deactivates this volume group. In addition, you should use the LVM vgexport command on the removed volume group from each node that will no longer be using the volume group.

Use the cmgetconf command to obtain a current copy of the cluster's existing configuration. Example:

# cmgetconf -c clconfig.ascii 

Edit the file clconfig.ascii to add or delete volume groups. Then use the cmcheckconf command to verify the new configuration. Use the cmapplyconf command to apply the changes to the configuration and send the new configuration file to all cluster nodes.

Following is an example for adding two volume groups:

# cmcheckconf -C clconfig.ascii vgname1 vgname2

If there are a large number of volume groups, you can use a reference file that lists all the volume groups. Example, using a reference file:

# cmcheckconf -C clconfig.ascii vgreferencefile

Following are examples of removing the volume groups that were added in the preceding examples:

# cmcheckconf -C clconfig.ascii vgname1 -R vgname2

# cmcheckconf -C clconfig.ascii vgreferencefile

Use the cmapplyconf command to apply the changes to the configuration and send the new configuration file to all cluster nodes. Syntax for the options with cmapplyconf is the same as given for the cmcheckconf command above.

	NOTE: If you are deleting from the cluster a volume group that is currently activated by a package, the configuration will be changed but the deletion will not take effect until the package is halted; thereafter, the package will no longer be able to run without further modification, such as removing the volume group from the package control script.

You can add VxVM disk groups to the cluster configuration while the cluster is running. To add new CVM disk groups, the cluster must be running.

Create CVM disk groups from this node. Open the configuration ASCII file of the package that uses the CVM storage; add the CVM storage group in a STORAGE_GROUP statement. Then issue the cmapplyconf command.

Similarly, you can delete VxVM or CVM disk groups provided they are not being used by a cluster node at the time.

	NOTE: If you are removing a disk group from the cluster configuration, make sure that you also modify or delete any package control script that imports and deports this disk group. If you are removing a CVM disk group, be sure to remove the STORAGE_GROUP entries for the disk group from the package ASCII file.