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Appendix A: Command Reference and the clinfo Utility
This appendix includes:
Command Reference
This section lists HACMP commands that are supported on HACMP for Linux. For further information on the commands, use their man pages. The command directory is /usr/es/sbin/cluster/man/cat1.
The majority of the utilities packaged with HACMP for AIX 5L are packaged with HACMP for Linux as well. However, some of the utilities may not fully work in release 5.4.
Note: The list of commands provided in this section is not guaranteed to be up-to-date or exhaustive, and is provided here as a reference only. In general, the HACMP user interface lets you perform all necessary actions in it, without having to use HACMP commands directly. The general rule of thumb is that everything you need to do is available to you via options in WebSMIT. If, however, a particular user interface option is not available in HACMP for Linux (it may be available in HACMP on AIX 5L), the corresponding CLI is also not supported on the Linux platform.
The clinfo Utility: Providing APIs to Interact with Other Applications
The HACMP software extends the benefits of highly available servers, data, and applications to client software applications by providing the clients with notification of cluster state changes through the Cluster Manager and the Cluster Information Program (clinfo).
The clinfo utility and its associated APIs enable developers to write applications that recognize and respond to changes in a cluster.
The clinfo utility includes:
Its own API. The clinfo utility provides the client API library. Use this library in client applications that you create. Your client applications can use socket connections to clinfo to retrieve cluster information. The clinfo API functions provide application developers with both a C and a C++ language interface for accessing cluster status information. The HACMP software includes two versions of the clinfo APIs: one for single-threaded applications and one for multi-threaded applications.
Scripts to communicate with the Cluster Manager. The clinfo utility gets cluster information from the Cluster Manager and allows clients communicating with it to be aware of a cluster’s state changes. Note: HACMP for Linux does not support SNMP as its communications protocol and therefore clinfo implementation in HACMP for Linux is different from clinfo implementation in HACMP for AIX 5L. On the Linux platform, the Cluster Manager services the clinfo client library directly.
At a high level, the clinfo utility works as follows:
The Cluster Manager, clstrmgr, listens on the clinfo client socket for clinfo API requests. The clinfo utility takes the cluster configuration information from the clstrmgr internal data structures. The clinfo utility stores information (retrieved from the Cluster Manager) in series of list structures, with a list for cluster nodes, networks and other cluster components. The client library API reads from the list structures. For complete information on clinfo and clients library API, see the HACMP for AIX 5L Programming Clients Applications Guide.
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