Using HP Serviceguard for Linux to Provide High Availability for LAMP, December 2005

Executive Summary

LAMP is an open source web server solution which is both powerful and stable that can

be used to create business applications. The acronym LAMP stands for Linux, Apache,

MySQL, and PHP/Perl/Python where Apache is the web server, MySQL the database,

and PHP/Perl/Python are server side scripting languages for creating dynamic web

pages. All these applications running on the open source OS, Linux, constitute the LAMP

stack.

Since the applications based on LAMP may be critical to a business, many customers

require that the LAMP components be “highly available”. HP Serviceguard for Linux can

be used to run these components in a cluster that has no single point of failure so that

application services are available despite hardware and software failure. This makes the

overall business application “Highly Available”.

This whitepaper describes how to use the existing HP Serviceguard for Linux contributed

toolkits to create a highly available and stable LAMP stack. This covers two configuration

options:

• A Consolidated LAMP Configuration where both the web server and the

database always run on the same server

• A Separate LAMP Configuration where the web server and the database run on

separate servers.

Introduction

With the maturity of the Linux Operating System, organizations today are looking to

deploy Linux for tasks that are more complex and more critical to their functioning. These

include system and network management, databases, project management tools, and

enterprise web applications. One such enterprise web application is the LAMP stack.

The individual components of the LAMP stack have been around for many years. But, the

collection of components is being increasingly viewed by vendors and customers as a

unified platform for building and running business applications. Such deployments

require that the applications be highly available and not be affected by a single point of

failure. The solution to this is to cluster multiple Linux servers together to build a highly

available environment.

HP Serviceguard for Linux is used to form a cluster of Linux servers and makes

application services available despite hardware or software failures or the planned

downtime required for maintenance or system upgrades. HP Serviceguard for Linux

monitors the LAMP stack and can respond to single or, sometimes, multiple failures within

the cluster. For example, when Serviceguard detects the failure of a node, it fails over

applications running on that node to other nodes in the cluster.

The existing Apache and MySQL toolkits for HP Serviceguard on Linux have been

leveraged to provide high availability to the LAMP components. This whitepaper

describes the procedure for setting up a highly available LAMP environment by using the

toolkits. The configuration instructions listed below are in addition to those in the Apache

and MySQL toolkit README’s. The instructions in the toolkit README’s must be followed