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

for every guest VM application that needs to be monitored.

A template for the `service_cmd` for application monitoring is as follows:

service_name cmappmon_srv1

service_cmd $SGLBIN/cmappmgr -node <VM_GUEST_HOSTNAME> -

cmappserver_timeout 30 -service <APP_PATH>

service_restart none

service_fail_fast_enabled no

service_halt_timeout 300

The parameters in the service template are similar to any SG/LX packaged service except for the

`service_cmd`.The ‘service_cmd’ is described below:

cmappmgr : Client component of the application monitoring service

<VM_GUEST_HOSTNAME> : Replace with the hostname of the Xen VM guest or an IP Address. The

hostname must be the same as mentioned in the /etc/cmappmgr.conf for truststore key.

cmappserver_timeout : This is the maximum time a ‘cmappmgr’ service can wait to make a

connection to ‘cmappserver’.This is a factor of the time required to boot up a Xen VM guest and

start the ‘cmappserver’ instance on the Xen VM guest. This should be an appropriate value for a

customer's environment.

service : The command required to start the Xen VM guest based application. This is the

application that is monitored by ‘cmappmgr’. Replace APP_PATH with absolute path of the command

binary.

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.