Appendix A. Virtual Machine Initial Start-Up Files

During the process of creating a new virtual machine, initial start-up settings are written to a file created at /etc/xen/vm/. During the creation process, the virtual machine starts according to settings in this file, but the settings are then transferred and stored in xend for ongoing operations.

[Important]

Modifying the initial start-up file to create or make changes to a virtual machine is not recommended. The preferred method for changing a virtual machine’s settings is to use Virtual Machine Manager as described in Section 5.3, “Configuring a Virtual Machine by Modifying its Xend Settings”.

When a virtual machine’s settings are stored in xend, it is referred to as a xen-managed domain or xen-managed virtual machine. Whenever the xen-managed virtual machine starts, it takes its settings from information stored in the xend database, not from settings in the initial start-up file.

Although it is not recommended, you might need to start an existing virtual machine based on settings in the initial start-up file. If you do this, any xend settings stored for the virtual machine are overwritten by the start-up file settings. Initial start-up files are saved to /etc/xen/vm/vm_name. Values must be enclosed in single quotes, such as localtime = '0'.

Table A.1. Initial start-Up File Entries and Descriptions

Entry

Description

disk =

Virtual disks for the virtual machine.

For example:

disk = [ 'file:/var/lib/xen/images/VM1_SLES10/hda,xvda,w' ]

This entry specifies a virtual disk based on a file ( file:) named hda and located at /var/lib/xen/images/VM1_SLES10/. It presents itself as the first drive (xvda) and has read/write access (w).

Disks can also be based on a block device.

memory =

Virtual memory in Mb.

vcpus =

Number of virtual CPUs.

builder =

Specifies paravirtual mode (Linux) or full virtualization mode (hvm).

name =

Name of the virtual machine.

vif =

Randomly-assigned MAC addresses and bridges assigned to use the virtual machine’s network addresses.

localtime =

Specifies a localtime (0) or UTC (1) time setting.

on_poweroff =

Specifies the action that the virtual machine performs when the operating system is powered off.

on_reboot =

Specifies the action that the virtual machine performs when the operating system reboots.

on_crash =

Specifies the action that the virtual machine performs when the operating system crashes.

extra =

Parameters passed to the kernel.

bootloader =

Location and filename of the domU boot loader.

bootentry =

Location of the kernel and initial ramdisk.

ostype =

Type of operating system.

uuid =

Identification number for a virtual drive.