Managing Serviceguard Nineteenth Edition, Reprinted June 2011

ip_subnet
Specifies an IP subnet used by the package for relocatable addresses; see also ip_address
(page 232) and “Stationary and Relocatable IP Addresses ” (page 64). Replaces SUBNET, which
is still supported in the package control script for legacy packages.
CAUTION: HP recommends that this subnet be configured into the cluster. You do this in the
cluster configuration file by specifying a HEARTBEAT_IP or STATIONARY_IP under a
NETWORK_INTERFACE on the same subnet, for each node in this package's NODE_NAME list. For
example, an entry such as the following in the cluster configuration file configures subnet
192.10.25.0 (lan1) on node ftsys9:
NODE_NAME ftsys9
NETWORK_INTERFACE lan1
HEARTBEAT_IP 192.10.25.18
See “Cluster Configuration Parameters ” (page 105) for more information.
If the subnet is not configured into the cluster, Serviceguard cannot manage or monitor it, and in
fact cannot guarantee that it is available on all nodes in the package's node-name list (page 223)
. Such a subnet is referred to as an external subnet, and relocatable addresses on that subnet are
known as external addresses. If you use an external subnet, you risk the following consequences:
• A failed interface on this subnet will not fail over to a local standby. See “Local Switching ”
(page 66) for more information about this type of failover.
• If the subnet fails, the package will not fail over to an alternate node.
• Even if the subnet remains intact, if the package needs to fail over because of some other type
of failure, it could fail to start on an adoptive node because the subnet is not available on that
node.
For these reasons, configure all ip_subnets into the cluster, unless you are using a networking
technology, such as HyperFabric, that does not support DLPI. In such cases, follow instructions in
the networking product's documentation to integrate the product with Serviceguard.
For each subnet used, specify the subnet address on one line and, on the following lines, the
relocatable IP addresses that the package uses on that subnet. These will be configured when the
package starts and unconfigured when it halts.
For example, if this package uses subnet 192.10.25.0 and the relocatable IP addresses
192.10.25.12 and 192.10.25.13, enter:
ip_subnet 192.10.25.0
ip_address 192.10.25.12
ip_address 192.10.25.13
If you want the subnet to be monitored, specify it in the monitored_subnet parameter as well.
In a cross-subnet configuration, you also need to specify which nodes the subnet is configured on;
see ip_subnet_node below. See also monitored_subnet_access (page 230) and “About
Cross-Subnet Failover” (page 145).
This parameter can be set for failover packages only.
Can be added or deleted while the package is running.
ip_subnet_node
In a cross-subnet configuration, specifies which nodes an ip_subnet is configured on. If no
ip_subnet_node are listed under an ip_subnet, it is assumed to be configured on all nodes
in this package’s node_name list (page 223).
Choosing Package Modules 231