Managing HP Serviceguard for Linux Ninth Edition, April 2009

/etc/sysconfig/network-scripts/ifcfg-<interface> on Red Hat or
/etc/sysconfig/network/ifcfg-<mac_address> on SUSE. The stationary IP
address is not associated with packages, and it is not transferable to another node.
Stationary IP addresses are used to transmit data, heartbeat messages (described under
“How the Cluster Manager Works ” (page 42)), or both. They are configured into the
cluster via the cluster configuration file; see the entries for HEARTBEAT_IP and
STATIONARY_IP under “Cluster Configuration Parameters ” (page 100).
Serviceguard monitors the subnets represented by these IP addresses. They are referred
to as monitored subnets, and you can see their status at any time in the output of the
cmviewcl command; see “Network Status” (page 225) for an example.
You can also configure these subnets to be monitored for packages, using the
monitored_subnet parameter in the package configuration file (page 204). A package will
not start on a node unless the subnet(s) identified by monitored_subnet in its package
configuration file are up and reachable from that node.
IMPORTANT: Any subnet identified as a monitored_subnet in the package configuration
file must be configured into the cluster via NETWORK_INTERFACE and either
STATIONARY_IP or HEARTBEAT_IP in the cluster configuration file. See “Cluster
Configuration Parameters ” (page 100) and “Package Parameter Explanations” (page 196).
In addition to the stationary IP address, you normally assign one or more unique IP
addresses to each package. The package IP address is assigned to a LAN interface when
the package starts up.
The IP addresses associated with a package are called relocatable IP addresses (also
known as IP aliases, package IP addresses or floating IP addresses) because the
addresses can actually move from one cluster node to another. You can use up to 200
relocatable IP addresses in a cluster spread over as many as 300 packages. These
addresses can be IPv4, IPv6, or a combination of both address families.
Because system multi-node and multi-node packages do not fail over, they do not have
relocatable IP address.
A relocatable IP address is like a virtual host IP address that is assigned to a package.
HP recommends that you configure names for each package through DNS (Domain
Name System). A program then can use the package’s name like a host name as the
input to gethostbyname(3), which will return the package’s relocatable IP address.
Relocatable addresses (but not stationary addresses) can be taken over by an adoptive
node if control of the package is transferred. This means that applications can access
the package via its relocatable address without knowing which node the package
currently resides on.
72 Understanding Serviceguard Software Components