Managing HP Serviceguard A.11.20.20 for Linux, May 2013

This shows that pkg1, when enabled, will “drag” pkg2 and pkg3 to its primary node, node1. It
can do this because of its higher priority; see “Dragging Rules for Simple Dependencies” (page 114).
Running cmeval confirms that all three packages will successfully start on node2 (assuming
conditions do not change between now and when you actually enable pkg1, and there are no
failures in the run scripts.)
NOTE: cmeval cannot predict run and halt script failures.
This is a simple example; you can use cmeval for much more complex scenarios; see “What You
Can Preview” (page 226).
IMPORTANT: For detailed information and examples, see the cmeval (1m) manpage.
7.6.2 Reconfiguring a Halted Cluster
You can make a permanent change in cluster configuration when the cluster is halted. This procedure
must be used for changes marked “Cluster must not be running” in Table 13, but it can be used
for any other cluster configuration changes as well.
Use the following steps:
1. Halt the cluster on all nodes.
2. On one node, reconfigure the cluster as described in “Building an HA Cluster Configuration”
(page 135). You can use cmgetconf to generate a template file, which you then edit.
3. Make sure that all nodes listed in the cluster configuration file are powered up and accessible.
Use cmapplyconf to copy the binary cluster configuration file to all nodes. This file overwrites
any previous version of the binary cluster configuration file.
4. Use cmruncl to start the cluster on all nodes, or on a subset of nodes.
7.6.3 Reconfiguring a Running Cluster
You can add new nodes to the cluster configuration or delete nodes from the cluster configuration
while the cluster is up and running. Note the following, however:
• You cannot remove an active node from the cluster. You must halt the node first.
• The only configuration change allowed while a node is unreachable (for example, completely
disconnected from the network) is to delete the unreachable node from the cluster configuration.
If there are also packages that depend upon that node, the package configuration must also
be modified to delete the node. This all must be done in one configuration request
(cmapplyconf command).
• The access control list for the cluster can be changed while the cluster is running.
Changes to the package configuration are described in a later section.
The following sections describe how to perform dynamic reconfiguration tasks.
7.6.3.1 Adding Nodes to the Configuration While the Cluster is Running
Use the following procedure to add a node. For this example, nodes ftsys8 and ftsys9 are
already configured in a running cluster named cluster1, and you are adding node ftsys10.
NOTE: Before you start, make sure you have configured access to ftsys10 as described under
“Configuring Root-Level Access” (page 136).
228 Cluster and Package Maintenance