16.3 The CLUA Subsystem - Beauty and Beast

16.3 The CLUA Subsystem – Beauty and Beast

We have established that we should create a cluster alias. We will associate it with an IP address that is not in use by any cluster members (nor can it be in use by any other nodes in the network or subnet within which the cluster resides). We now need to associate the newly selected cluster alias IP address with a MAC address. Unfortunately, we cannot just fabricate a MAC address (more on this later), but we can associate multiple IP addresses with an individual network device. This sets up an IP alias for the interface. Sounds like all we have to do is set up an IP alias using the selected IP address through the ifconfig(8) command, and we will be ready to have clients use the cluster alias.

Once again, it sounds like we are back to causing the selected cluster member to be potentially overloaded with network services, since all of the requests from clients will be using the cluster alias IP address, which will be translated into the MAC address for an interface on the selected cluster member.

Note

Do not confuse the cluster alias with an IP interface alias. The concepts are similar. See the ifconfig(8) reference page for information on the creation of an IP alias for the interface.