IP Interface Selection

When creating an IP resource, select the IP resource address, the netmask to use with the address and the network interface. Not all combinations are allowed. The address/netmask pair provided and all the address/netmask pairs currently in-service determine choices. Also, see the section on IP Local Recovery for additional configuration considerations if planning on using this feature of the recovery kit.

The selected address/netmask determines the subnet for the resource. If another address on the same subnet (either a physical or logical interface address) is currently in service on any interface, then the IP resource must be configured on that interface. The software performs tests to determine the allowed choices based upon the current network configuration. Select from any of the choices provided.

Because the IP Recovery Kit software does not distinguish between physical media types, the physical network for the resource must be determined and the address selected appropriately. For example, assume that you have a server connected to an Ethernet backbone on subnet xx.yy.12 and Ethernet LANs on subnets xx.yy.20 and xx.yy.30. If you want to create a resource on the first Ethernet subnet, select an address on that subnet, such as xx.yy.20.120.

In general, even though the IP Recovery Kit software allows you to select almost any value for the netmask, you should avoid selecting multiple netmasks for the same physical interface because multiple masks can cause packet misrouting.

One further consideration is the need to be consistent in your selection of interfaces on all LifeKeeper servers. If you configure several IP resources on a single interface on Server A, they should also be configured on a single interface on Server B.

When creating an IP resource hierarchy, you may utilize any interface which is initially UP and has a corresponding and correct network interface configuration file on both the primary and backup hosts, i.e. if using eth1, eth1 must be UP and eth1 must have a corresponding and correct ifcfg-eth1 file (test with ifup/ifdown ifcfg-eth1) even if the configuration is minimal without any address assignments or is DOWN on boot.