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HP Serviceguard Tasks
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This section provides examples of common tasks you perform for HP XC systems that use HP Serviceguard as the availability tool. For more in-depth information on Serviceguard, see the HP Serviceguard documentation at the following Web site:

http://docs.hp.com/en/ha.html#Serviceguard

Each availability set relates to a corresponding Serviceguard cluster.

NOTE: In the examples in this section, assume the PATH environment variable has been updated for Serviceguard commands.

Viewing the Serviceguard Cluster Status

View the status of the Serviceguard cluster (that is, the availability set). The Serviceguard cmviewcl command is a key component of this procedure.

NOTE: The /usr/local/cmcluster/bin directory is the default location of the cmviewcl command. If you installed Serviceguard in a location other than the default, look in the /etc/cmcluster.conf file for the location of the Serviceguard bin directory.

  1. Log in as superuser (root) on the head node.

  2. Use the shownode config hostgroups command to determine which nodes are in each availability set:

    # shownode config hostgroups
hostgroups:
headnode:               n16
serviceguard:avail1:    n14
                        n16
serviceguard:avail2:    n13
                        n12

  3. Use the Serviceguard cmviewcl command on one node of each availability set to view the status of the Serviceguard cluster. For example:

    # pdsh -w n13,n14 /usr/local/cmcluster/bin/cmviewcl
n13:
n13: CLUSTER      STATUS
n13: avail2       up
n13:
n13:   NODE         STATUS       STATE
n13:   n12          up           running
n13:
n13:     PACKAGE      STATUS       STATE        AUTO_RUN     NODE
n13:     n12          up           running      enabled      n12
n13:
n13:   NODE         STATUS       STATE
n13:   n13          up           running
n13:
n13:     PACKAGE      STATUS       STATE        AUTO_RUN     NODE
n13:     nat.n13      up           running      enabled      n13
n14:
n14: CLUSTER      STATUS
n14: avail1       up
n14:
n14:   NODE         STATUS       STATE
n14:   n14          up           running
n14:
n14:     PACKAGE      STATUS       STATE        AUTO_RUN     NODE
n14:     nat.n14      up           running      enabled      n14
n14:
n14:   NODE         STATUS       STATE
n14:   n16          up           running
n14:
n14:     PACKAGE         STATUS       STATE        AUTO_RUN     NODE
n14:     nat.n16         up           running      enabled      n16
n14:     lvs.n16         up           running      enabled      n16
n14:     nagios.n16      up           running      enabled      n16
n14:     dbserver.n16    up           running      enabled      n16

    The cmviewcl command views the status of all Serviceguard clusters that correspond to the avail1 and avail2 availability sets.

Moving Packages

The following example describes how to relocate packages manually within a Serviceguard cluster (availability set). You can use the steps shown in this example to failback HP Serviceguard packages manually after an automatic failover.

  1. Nodes n12 and n13 are assigned to an HP Serviceguard cluster. A package named pack1 runs on node n12.

  2. Use the cmhaltpkg command to halt the pack1 package on node n12:

    # pdsh -w n12 cmhaltpkg pack1

  3. After the pack1 package stops, run the package on node n13:

    # pdsh -w n13 cmrunpkg -n n11 pack1

    Note that the command is issued on node n12 to run the package on n13.

  4. Enable automatic failover of the HP Serviceguard package:

    # pdsh -w n13 cmmodpkg -e pack1

Reimaging Nodes in the Availability Set

Reimaging a node is the means by which you update software on a node from a central repository, called a golden master. Chapter 10 discusses this topic in detail.

Nodes must be stopped and restarted during the reimaging process.

When a node is reimaged, but its partner in an availability set is still running, the reimaged node comes under the control of the availability tool automatically.

When both or all the nodes in an availability set are down, you must use the transfer_to_avail command on the head node to transfer control of services to the availability tool.

Consider the example of two HP Serviceguard clusters: one comprising nodes n12 and n13, and the other comprising nodes n14 and n16. Node n16 is the head node. The sequence of events is as follows:

  1. The golden image on node n16 is updated so that the software can be propagated to the other nodes.

  2. Nodes n12, n13, and n14 are stopped so that they can be reimaged.

    Node n16 is still running.

  3. When node n14 starts up again, it automatically joins its Serviceguard cluster. It does so because node n16, its partner, is up and running a Serviceguard cluster.

  4. When nodes n12 and n13 start up, they do not form their Serviceguard cluster. You must issue the transfer_to_avail command on the head node to transfer control of services to their Serviceguard cluster. In this example, the transfer_to_avail command is run on the head node. This command ignores Serviceguard clusters that are already running and start the other clusters that are not.

    # transfer_to_avail

  5. Both nodes, n12 and n13, are up because they are reimaged. The control of their services is transferred to Serviceguard.



Availability Sets
  		 


Transferring Control of Services  
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