Designing High-Availability for Xen Virtual Machines with HP Serviceguard for Linux, September 2008

1. To get the virtual machine ID of the virtual machine “s102vm1” , use the command

xm list | grep “s102vm1” | awk ‘{print $2}’

2. Now use the ‘vmid’ to get the name of the virtual interface that is mapped to the virtual

machine on the dom0 host.

vif < vmid >.<interface index>

so, the derived interface is ‘vif2.0’

3. Probe the interface using the command

‘ifconfig vif2.0 | grep “UP”’.

vif2.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF

inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link

UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

RX packets:805 errors:0 dropped:0 overruns:0 frame:0

TX packets:3744 errors:0 dropped:18 overruns:0 carrier:0

collisions:0 txqueuelen:32

RX bytes:26624 (26.0 Kb) TX bytes:247301 (241.5 Kb)

The virtual machine network can be monitored from the host by simply probing the 'vif' interface

associated with the VM.

A failure of the physical interface or the virtual machine would bring the virtual interface down, thus

notifying that the network on the virtual machine has failed.

Serviceguard for Linux can then fail the package and restart it on a different node where the network

is available. Repeat the steps listed above to identify the new virtual interface on the other node and

monitor it accordingly.

Summary

Protecting Xen virtual machines with clustering provided by Serviceguard for Linux delivers lower total

cost of ownership by enabling Xen virtual machines to be used for business critical applications. This

consolidation leads to an overall reduced data center footprint.

Requirements:

 Install ‘kernel-xen-devel’ rpm on all nodes configured as Xen dom0 nodes. The rpm

does not get installed by default on RHEL5. SLES10 installs the package by default when

configured through Yast2 tool. The package is required for successful installation of the

SG/LX rpm.

 The Xen Control and Management Script is necessary to automate the start, stop and

monitor operations for a VM when configured as a Serviceguard for Linux package.

Refer Appendix I, II and II for developing the Xen control and management script.

 Serviceguard for Linux require specific configurations at install time mentioned earlier.

These requirements are mandatory to ensure proper operation of SG/LX on a Xen dom0

platform.

 Modification to the grub bootloader sequence is required to ensure that the machines

boots into Xen by default.