HP XC System Software Installation Guide Version 3.1

1.8 Task 8: Purchase Additional Software from HP and Third-Party Vendors
An HP XC system supports the use of several additional HP and third-party software products. Use of
these products is optional; the purchase and installation of these components is your decision and depends
on your site's requirements. Product licensing requirements differ by product.
“Task 4: Install Additional Software from Local Distribution Media” (page 40) describes the HP and
third-party products you may need to install.
Compilers and Debuggers
The HP XC software does not bundle, nor does HP resell, the TotalView debugger or the Intel and The
Portland Group compilers. You are responsible for purchasing and licensing these compilers from the
third-party vendors.
1.9 Task 9: Plan a Service Availability Strategy
This task describes how to configure some services with improved availability. HP recommends that you
read this entire section to learn what improved availability means, how it is achieved, and which services
are eligible for improved availability.
Some advance planning is required if you want to configure improved availability of services. HP
recommends that you take the time to perform planning exercises now, before proceeding any further to
prepare the system and gather the information required by the cluster_config utility.
This section addresses the following topics:
• “What Is Improved Availability?” (page 26)
• “How to Configure Improved Availability” (page 27)
• “Choose an Availability Tool” (page 27)
• “Write Translator and Other Supporting Scripts” (page 28)
• “Choose Nodes as Members of Availability Sets” (page 28)
• “Role Assignments for Improved Availability” (page 28)
• “Use the Improved Availability Planning Worksheet” (page 30)
1.9.1 What Is Improved Availability?
A service availability infrastructure is built into the HP XC System Software, which enables an availability
tool to fail over a subset of services to nodes that have been designated as a second server of the service.
Improved availability protects against service failure if a node that is serving vital services becomes
unresponsive or goes down.
You have the flexibility to decide which availability tool you want to use to manage and migrate specified
services to a second server if the first server is not available. You can install one or more availability tools
to manage the services that have been configured for improved availability. The availability tool is
responsible for starting, stopping, and monitoring those services; you do not use HP XC commands for
those tasks.
The HP Serviceguard product is the recommended availability tool, but you can install and configure
other third party tools of your choice. If you install an availability tool other than Serviceguard, the
third-party vendor or the product documentation is responsible for providing customer support for the
tool.
How Does Availability Work?
Using the procedures described in this document, you use the cluster_config utility to assign a service
or services to be served from two nodes through a mechanism called an availability set. An availability
set associates two individual nodes so that one node acts as the first server and the other node acts as the
second server of the service.
The cluster_config utility associates the service with an IP address alias (for example, 172.20.64.200).
Client nodes are configured to connect to the service by communicating with the IP alias.
The availability tool is responsible for configuring the IP alias and for starting the service on the primary
server. The tool is also responsible for detecting if a node becomes unresponsive or unavailable. If that
26 Preparing for a New Installation