Computer Hardware User Manual

44 IBM Certification Study Guide AIX HACMP
2.6 Customization Planning
The Cluster Manager’s ability to recognize a specific series of events and
subevents permits a very flexible customization scheme. The HACMP for AIX
software provides an event customization facility that allows you to tailor
cluster event processing to your site.
2.6.1 Event Customization
As part of the planning process, you need to decide whether to customize
event processing. If the actions taken by the default scripts are sufficient for
your purposes, you do not need to do anything further to configure events
during the installation process.
If you decide to tailor event processing to your environment, it is strongly
recommended that you use the HACMP for AIX event customization facility
described in this chapter. If you tailor event processing, you must register
user-defined scripts with HACMP during the installation process. The
HACMP
for AIX, Version 4.3: Installation Guide
, SC23-4278 describes how to
configure event processing for a cluster.
You cannot define additional cluster events.
You can, however, define
multiple pre- and post-events for each of the events
defined in the HACMPevent ODM class.
The event customization facility includes the following features:
• Event notification
• Pre- and post-event processing
• Event recovery and retry
2.6.1.1 Special Application Requirements
Some applications may have some special requirements that have to be
checked and ensured before or after a cluster event happens. In case of a
failover you can customize events through the definition of pre- and post-
events, to act according to your application’s needs. For example, an
application might want to reset a counter or unlock a user before it can be
started correctly on the failover node.
2.6.1.2 Event Notification
You can specify a
notify command that sends mail to indicate that an event is
about to happen (or has just occurred), and that an event script succeeded or
failed. For example, a site may want to use a network_down notification