IP labels
In a environment that is not using PowerHA® SystemMirror®, a host name typically identifies a system, with the host name also being the IP label of one of the network interfaces in the system. Thus, a system can be reached by using its host name as the IP label for a connection.
Host name resolution
In PowerHA SystemMirror, all node host names must be resolved locally with the /etc/hosts file. When defining nodes to the cluster, you must specify an IP address or label that resolves locally to the host name, and after you have synchronized the initial cluster configuration, the host name of the node might not be changed.
IP labels in TCP/IP networks
For TCP/IP networks, an IP label and its associated IP address must appear in the /etc/hosts file.
The name of the service IP label or address must be unique within the cluster and distinct from the volume group and resource group names. It should relate to the application it serves, as well as to any corresponding device, such as websphere_service_address.
When you assign a service IP label to an interface, use a naming convention that helps identify the interface's role in the cluster. The related entries in the /etc/hosts file would be similar to the following:
100.100.50.1 net1_en0
100.100.60.1 net2_en1You configure the network interface controller (NIC) by following the instructions in the relevant AIX® documentation. AIX assigns an interface name to the NIC when it is configured. The interface name is made up of 2 or 3 characters that indicate the type of NIC, followed by a number that AIX assigns in sequence for each adapter of a certain type. For example, AIX assigns an interface name such as en0 for the first Ethernet NIC it configures, en1 for the second, and so on.