Using HP Serviceguard for Linux with VMware

Executive Summary

Virtual machine technology is a powerful capability that can reduce costs and power usage while

improving utilization of resources. HP is also applying virtualization to other aspects of the data center

and uniting virtual and physical resources to create an environment suitable for deploying mission-

critical applications.

HP Serviceguard for Linux A.11.18.02 (A.11.18 with the October 2007 patches) is certified for

deployment on Linux Virtual machines created on VMware ESX server 3.0.2

running 32-bit and 64-

bit versions of RedHat 4 U5, RedHat 5, and SLES10 on HP industry-standard ProLiant (x86-based)

servers

. You can configure Serviceguard clusters consisting of physical and virtual machines

running these certified Linux distributions.

This white paper provides information on configuring a Serviceguard for Linux cluster that includes

virtual machines; it also makes recommendations for eliminating single points of failure and provides

ointers to other useful documents. p

Introduction

Virtual machines on VMware are being deployed increasingly for server consolidation and

flexibility. Virtual machine technology allows one physical server to simulate multiple servers, each

concurrently running its own operating system (OS). In virtual machine technology, the virtualization

layer also known as hypervisor

abstracts the physical resources so that each instance of an OS

appears to have its own Network Interface card (NIC), processor, disk, and memory, when in fact

they are virtual instances. This allows you to replace a number of existing physical servers with just

one, but at the cost of greater exposure to failures. Where previously, one server failure only

affected the applications running on it, now a physical server failure results in a number of virtual

servers failing along with ALL of their applications.

VMware has a high availability (HA) clustering product called VMware HA. It can provide some

degree of protection from failures, but it has its limitations. VMware HA uses a simple model that

detects only physical server failures. When it detects those failures it restarts the Virtual Machines from

the failed server on other servers running VMware. Running Serviceguard for Linux in the virtual

machines provides a significant level of extra protection. Specifically, Serviceguard for Linux fails

over an application when any of a large number of failures occurs, including:

• A failure of the application

• A failure of networking required by the application

• Failure of storage

• An operating system “hang” or failure of the virtual machine itself

• Failure of the physical machine

here are other advantages beyond the increased failure protection.

• Serviceguard for Linux failover is faster than VMware HA. Serviceguard for Linux restarts just

the application, while VMware HA requires the Virtual Machine’s operating system to boot

on the failover target before restarting the application.

The term ESX server used in this whitepaper refers to the release ESX Server 3.0.2. 2

3 As on July 2007, HP offers a total of 39 platforms across more than one generation for several of the ProLiant servers. For latest information,

see http://www.vmware.com/pdf/vi3_systems_guide.pdfwww.hp.com/go/vmware.

In future, Serviceguard for Linux will be certified on VMware ESX Server certified servers from Sun, IBM and Dell.

Hypervisor often refers to a layer that resides directly on server hardware, but terms are not used consistently across the industry.