====== Xen ======

  * [[CentOS Xen]]
  * [[Gentoo Xen]]
  * [[NetBSD Xen]]
  * [[System Rescue CD Xen]]
  * [[Ubuntu Xen]]
  * [[xen-create-image]]
  * [[xl]]
  * [[xm]]

  * [[http://wiki.xen.org/wiki/PyGrub|PyGrub]]
  * http://wiki.xen.org/wiki/Xen_Overview
  * http://wiki.xen.org/wiki/XCP_Ubuntu_Install
  * https://help.ubuntu.com/community/Xen
  * [[http://xenbits.xen.org/docs/unstable/misc/xen-command-line.html|Xen Hypervisor Command Line Options]]
  * [[https://wiki.debian.org/Xen|Debian Wiki - Xen]]
  * [[http://wiki.centos.org/HowTos/Xen/InstallingCentOSDomU|Creating and installing a CentOS 5 domU]]
  * [[http://grantmcwilliams.com/tech/virtualization/xen-howtos/|Grant McWilliams Xen howtos]] - good scripts to bootstrap Linux domUs
  * [[http://wiki.xen.org/wiki/XenConfigurationFileOptions|Xen Configuration Options]] - for xen.cfg

==== Xen Guest Config File ====

Options for config entries for a guest:

  * **name** - domain name
  * **builder** - the type of domain. ''generic'' uses the default, which is a PV domain, with ''hvm'' being the second option.
  * **vcpus** - number of virtual CPUs to start the guest with
  * **memory** - start with # MBs of RAM
  * **on_poweroff** - specifics on what to do when a domain shuts itself down:
    * **destroy** - default
    * **restart**
    * **rename-restart** - rename the domain that was created, and create a new one with the same config
    * **preserve** - keep the domain name that was created
  * **on_reboot**, **on_crash** - same options as before
  * **uuid** - specify a UUID for the domain; by default Xen creates one

=== Paravirtualised (PV) Guest Specific Options ===

Paravirtulized is the default type of guest emulation.

  * **kernel** - location of the kernel image on domain filesystem; this or ''bootloader'' must be used
  * **ramdisk** - location of the ramdisk on domain filesystem
  * **bootloader** - program to run to find the kernel image and ramdisk to use; normally would be ''pygrub'', which is an emulation of either grub, grub2, and syslinux.
  * **bootloader_args**
  * **root** - value of ''root='' to pass to kernel (fex: ''root /dev/xvda3'' in Xen config becomes ''root=/dev/xvda3'' in kernel command line)
  * **extra** - string to append to the kernel command line (fex: ''acpi=off'')

=== Disks ===

Format: ''disk = [ "DISK_SPEC_STRING", "DISK_SPEC_STRING", ... ]''

Give the guest read-write access to a device, and set it as ''/dev/xvda'':

<code>
disk= [ 'phy:/dev/sdc,xvda,rw' ]
</code>

** Booting from CD **

Same configuration as above, but with an ISO attached, as device ''/dev/hdc''. Note that ''pygrub'' will boot from the **first device** in the list.

<code>
disk= [ 'file:/var/isos/gentoo.iso,hdc:cdrom,r', 'phy:/dev/sdc,xvda,rw' ]
</code>

If you'd like to boot from the ISO, add this to your Xen guest config:

<code>
boot = 'c'
</code>