Managing Serviceguard Nineteenth Edition, Reprinted June 2011

• You cannot add interfaces or modify their characteristics unless those interfaces, and all other
interfaces in the cluster configuration, are healthy.
There must be no bad NICs or non-functional or locally switched subnets in the configuration,
unless you are deleting those components in the same operation.
• You cannot change the designation of an existing interface from HEARTBEAT_IP to
STATIONARY_IP, or vice versa, without also making the same change to all peer network
interfaces on the same subnet on all other nodes in the cluster.
Similarly, you cannot change an interface from IPv4 to IPv6 without also making the same
change to all peer network interfaces on the same subnet on all other nodes in the cluster
• You cannot change the designation of an interface from STATIONARY_IP to HEARTBEAT_IP
unless the subnet is common to all nodes.
Remember that the HEARTBEAT_IP must on the same subnet on all nodes, except in
cross-subnet configurations; see “Cross-Subnet Configurations” (page 29).
• You cannot delete a primary interface without also deleting any standby interfaces, unless the
standby is being used by another primary interface that is not being deleted.
• You cannot delete a subnet or IP address from a node while a package that uses it (as a
monitored_subnet, ip_subnet, or ip_address) is configured to run on that node.
See the package networking parameter descriptions (page 229) for more information.
• You cannot change the IP configuration of an interface (NIC) used by the cluster in a single
transaction (cmapplyconf).
You must first delete the NIC from the cluster configuration, then reconfigure the NIC (using
ifconfig (1m), for example), then add the NIC back into the cluster.
Examples of when you must do this include:
◦ moving a NIC from one subnet to another
◦ adding an IP address to a NIC
◦ removing an IP address from a NIC
CAUTION: Do not add IP addresses to network interfaces that are configured into the
Serviceguard cluster, unless those IP addresses themselves will be immediately configured into
the cluster as stationary IP addresses. If you configure any address other than a stationary IP
address on a Serviceguard network interface, it could collide with a relocatable package
address assigned by Serviceguard.
Some sample procedures follow.
Example: Adding a Heartbeat LAN
Suppose that a subnet 15.13.170.0 is shared by nodes ftsys9 and ftsys10 in a two-node
cluster cluster1, and you want to add it to the cluster configuration as a heartbeat subnet.
Proceed as follows.
Reconfiguring a Cluster 285