Configuring a kernel image file as IPL device

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As an alternative to booting an installed guest from a DASD or a SCSI disk, you might want to boot from a kernel image file residing on the host for setup purposes.

Procedure

  1. Specify the initial ramdisk, the kernel image file, and the kernel parameters.

    You get this information from the installation file and the parameter file of your product or distribution.

    1. Specify the fully qualified path to the initial ramdisk on the host with the initrd element, which is a child of the os element (see <initrd>).
      initrd element: <initial-ramdisk>
    2. Specify the fully qualified path to the kernel image file in the kernel element, which is a child of the os element (see <kernel>).
      kernel element: <kernel-image-file>
    3. Pass command-line arguments to the installer by using the cmdline element, which is a child of the os element (see <cmdline>).

      You can use the command line parameters that are supported by your product or distribution.

      cmdline element: <command-line-arguments>
  2. Configure all disks that are needed for the boot process as persistent devices.

    If you are booting from the kernel image file as an initial installation, make sure to provide a disk for the guest installation.

  3. For guests that are to run in IBM® Secure Execution mode and cannot use the launchSecurity element in the virtual server configuration, ensure that the device uses the guest's bounce buffer, see Preparing the virtual server.
    Kernel images for IBM Secure Execution for Linux, typically, include all data that is required for booting, so no separate initrd and cmdline are present.

Example

  1. Specify the kernel image file in the os element:
    <os>
    ...
    <initrd>initial-ramdisk</initrd>
    <kernel>kernel-image</kernel>
    <cmdline>command-line-parameters</cmdline>
</os>
  2. Provide a disk for the guest installation:
    <disk type="block" device="disk">
    <driver name="qemu" type="raw" cache="none" io="native" iothread="2"/>
    <source dev="/dev/mapper/36005076305ffc1ae00000000000021d7"/>
    <target dev="vdb" bus="virtio"/>
    <address type="ccw" cssid="0xfe" ssid="0x0" devno="0xe716"/>
</disk>

What to do next

When configuring a different boot device with the boot element, for example the disk for the guest installation, you must remove the os element. The boot and os elements are mutually exclusive.
Draft comment: HorstWeber
Does virt-xml resolve this or is this outside the scope of the virt-xml use case?