Adding and Deleting Relocatable IP Addresses

The IP addresses associated with a package are called relocatable IP addresses (also known as package IP addresses or floating IP addresses) because the addresses can actually move from one cluster node to another on the same subnet. You can use up to 200 relocatable IP addresses in a cluster. 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 Service). A program can then use the package’s name like a host name as the input to gethostbyname, which will return the package's relocatable IP address.

Both stationary IP addresses, and relocatable IP addresses on subnets that are configured into the cluster, will switch to a standby LAN interface in the event of a LAN card failure.

In addition, relocatable addresses (but not stationary addresses) can be taken over by an adoptive node on the same subnet 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.

IMPORTANT: Any subnet that is used by a package for relocatable addresses should be configured into the cluster via NETWORK_INTERFACE and either STATIONARY_IP or HEARTBEAT_IP in the cluster configuration file. For more information about those parameters, see “Cluster Configuration Parameters ” (page 109). For more information about configuring relocatable addresses, see the descriptions of the package ip_ parameters (page 242).

NOTE: It is possible to configure a cluster that spans subnets joined by a router, with some nodes using one subnet and some another. This is called a cross-subnet configuration. In this context, you can configure packages to fail over from a node on one subnet to a node on another, and you will need to configure a relocatable address for each subnet the package is configured to start on; see “About Cross-Subnet Failover” (page 154), and in particular the subsection “Implications for Application Deployment” (page 155).

Types of IP Addresses

Both IPv4 and IPv6 address types are supported in Serviceguard. IPv4 addresses are the traditional addresses of the form n.n.n.n where n is a decimal digit between 0 and 255. IPv6 addresses have the form x:x:x:x:x:x:x:x where x is the hexadecimal value of each of eight 16-bit pieces of the 128-bit address. You can define heartbeat IPs, stationary IPs, and relocatable (package) IPs as IPv4 or IPv6 addresses (or certain combinations of both).