16.11 CAA vs. CLUA


16.11 CAA vs. CLUA

So far, this chapter has explained what happens when services are started as necessary by the inetd daemon. There are other network services that are started at boot time such as NFS, DNS/BIND, and NIS. These services are usually controlled though the CAA subsystem (See Chapter 24 for CAA examples). CAA is designed to manage applications that run on a single cluster member at a time. Contrast that with the CLUA subsystem, which is tasked with the routing of client connection requests addressed to cluster aliases. Sometimes the concepts of CAA and CLUA seem to blur, but if you remember that CLUA involves cluster alias routing decisions, and CAA involves starting, managing, and failing over applications, the distinctions should become clear.

CAA will be most useful on applications with the in_single CLUA attribute. CAA will be responsible for starting applications under its control, failing over applications when necessary, and monitoring the availability of any resources necessary for the CAA controlled application to run. See Chapters 23 and 24 for more information on CAA.




TruCluster Server Handbook
TruCluster Server Handbook (HP Technologies)
ISBN: 1555582591
EAN: 2147483647
Year: 2005
Pages: 273

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