Managing HP Serviceguard for Linux, Tenth Edition, September 2012

ip_subnet
Specifies an IP subnet used by the package. 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 103) 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 206) . 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:
• 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 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
(page 212) 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 213) and “About Cross-Subnet Failover” (page 151).
214 Configuring Packages and Their Services