Trace: • xen

Xen

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: 

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

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. 

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

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

boot = 'c'