Managing HP Serviceguard for Linux, Tenth Edition, September 2012

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.
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 158).
1. Use the following command to store a current copy of the existing cluster
configuration in a temporary file in case you need to revert to it:
cmgetconf -C temp.conf
2. Specify a new set of nodes to be configured and generate a template of the new
configuration (all on one line):
cmquerycl -C clconfig.conf -c cluster1 -n ftsys8 -n ftsys9
-n ftsys10
3. Edit clconfig.conf to check the information about the new node.
4. Verify the new configuration:
cmcheckconf -C clconfig.conf
5. Apply the changes to the configuration and send the new binary configuration file
to all cluster nodes:
cmapplyconf -C clconfig.conf
Use cmrunnode to start the new node, and, if you so decide, set the AUTOSTART_CMCLD
parameter to 1 in the $SGAUTOSTART file (see “Understanding the Location of
Serviceguard Files” (page 156)) to enable the new node to join the cluster automatically
each time it reboots.
Reconfiguring a Cluster 265