As discussed in Chapter 6 and touched upon elsewhere in this book, Xen supports a number of different mechanisms for defining virtual machines and storing their configuration information. Most commonly, Xen virtual machine configuration information is stored in text files in Python variable format, making it easy to examine and update that configuration information. Links to these configuration files can be placed in
/etc/xen/auto to automatically restart specific virtual machines whenever you restart a domain0 system.
If you are using Xen's lifecycle management (discussed in Chapter 9) the configuration information in these files can be loaded into the XenStore and preserved there, making this configuration information persistent and simplifying scripted system restarts. Once in the XenStore, virtual machine configuration information can also be displayed in standard formats such as SXP and XML. Distributions such as Fedora and Red Hat provide utilities such as virt-manager for graphically defining, storing, and editing configuration information for Xen virtual machines. As with Xen's lifecycle management, virt-manager stores this configuration information in the XenStore.
Regardless of how you define your Xen virtual machines and where their configuration information is stored, the configuration parameters that are supported by Xen are the key to your Xen virtual machines. This appendix discusses all of the virtual machine ...