Build an OEM Expandable Disk Image

An OEM disk represents the system disk with the capability to auto expand the disk and its filesystem to a custom disk geometry. This allows deploying the same OEM image on target systems of a different hardware setup.

The following example shows how to build and deploy an OEM disk image based on openSUSE Leap using a QEMU virtual machine as OEM target system:

  1. Make sure you have checked out the example image descriptions, see Example Appliance Descriptions.

  2. Build the image with KIWI:

    $ sudo kiwi-ng --type oem system build \
        --description kiwi-descriptions/suse/x86_64/suse-leap-42.3-JeOS \
        --target-dir /tmp/myimage
    

    Find the following result images below /tmp/myimage.

    • The OEM disk image with the suffix .raw is an expandable virtual disk. It can expand itself to a custom disk geometry.
    • The OEM installation image with the suffix install.iso is a hybrid installation system which contains the OEM disk image and is capable to install this image on any target disk.

Deployment Methods

The basic idea behind an OEM image is to provide the virtual disk data for OEM vendors to support easy deployment of the system to physical storage media.

There are the following basic deployment strategies:

  1. Manual Deployment

    Manually deploy the OEM disk image onto the target disk

  2. CD/DVD Deployment

    Boot the OEM installation image and let KIWI’s OEM installer deploy the OEM disk image from CD/DVD or USB stick onto the target disk

  3. Network Deployment

    PXE boot the target system and let KIWI’s OEM installer deploy the OEM disk image from the network onto the target disk

Manual Deployment

The manual deployment method can be tested using virtualization software such as QEMU, and an additional virtual target disk of a larger size. The following steps shows how to do it:

  1. Create a target disk

    $ qemu-img create target_disk 20g
    

    Note

    Retaining the Disk Geometry

    If the target disk geometry is less or equal to the geometry of the OEM disk image itself, the disk expansion performed for a physical disk install during the OEM boot workflow will be skipped and the original disk geometry stays untouched.

  2. Dump OEM image on target disk

    $ dd if=LimeJeOS-Leap-42.3.x86_64-1.42.3.raw of=target_disk conv=notrunc
    
  3. Boot the target disk

    $ qemu -hda target_disk -m 4096
    

    At first boot of the target_disk the system is expanded to the configured storage layout. By default the system root partition and filesystem is resized to the maximum free space available.

CD/DVD Deployment

The deployment from CD/DVD via the installation image can also be tested using virtualization software such as QEMU. The following steps shows how to do it:

  1. Create a target disk

    Follow the steps above to create a virtual target disk

  2. Boot the OEM installation image as CD/DVD with the target disk attached

    $ qemu -cdrom LimeJeOS-Leap-42.3.x86_64-1.42.3.install.iso -hda target_disk -boot d -m 4096
    

    Note

    USB Stick Deployment

    Like any other iso image built with KIWI, also the OEM installation image is a hybrid image. Thus it can also be used on USB stick and serve as installation stick image like it is explained in Build an ISO Hybrid Live Image

Network Deployment

The deployment from the network downloads the OEM disk image from a PXE boot server. This requires a PXE network boot server to be setup as explained in Setting Up a Network Boot Server

If the PXE server is running the following steps shows how to test the deployment process over the network using a QEMU virtual machine as deployment target system:

  1. Make sure to create an installation PXE TAR archive along with your OEM image by replacing the following setup in kiwi-descriptions/suse/x86_64/suse-leap-42.3-JeOS/config.xml

    instead of
    
    <type image="oem" installiso="true" ...
    
    setup
    
    <type image="oem" installpxe="true" ...
    
  2. Rebuild the image, unpack the resulting LimeJeOS-Leap-42.3.x86_64-1.42.3.install.tar.xz file to a temporary directory and copy the initrd and kernel images to the PXE server:

    mkdir /tmp/pxe && cd /tmp/pxe
    tar -xf LimeJeOS-Leap-42.3.x86_64-1.42.3.install.tar.xz
    scp initrd-oemboot-*.install.* PXE_SERVER_IP:/srv/tftpboot/boot/initrd
    scp initrd-oemboot-*.kernel.* PXE_SERVER_IP:/srv/tftpboot/boot/linux
    

    Also copy the OEM disk image and the md5 sum to the PXE boot server

    scp LimeJeOS-Leap-42.3.x86_64-1.42.3.xz PXE_SERVER_IP:/srv/tftpboot/image/
    scp LimeJeOS-Leap-42.3.x86_64-1.42.3.md5 PXE_SERVER_IP:/srv/tftpboot/image/
    
  3. Copy the kernel command line parameters from LimeJeOS-Leap-42.3.x86_64-1.42.3.append. Edit your PXE configuration (for example pxelinux.cfg/default) on the PXE server and add these parameters to the append line

    Optionally the image and its md5sum can be stored on an FTP or HTTP server specified via the parameters kiwiserver=IP_ADRESS and kiwiservertype=HTTP_HTTPS_OR_FTP. In this case make sure to copy the system image and md5 file to the correct location on the server. KIWI searches the image below SERVER_ROOT/image/

    Note

    The initrd and Linux Kernel are always loaded via tftp from the PXE_SERVER.

  4. Create a target disk

    Follow the steps above to create a virtual target disk

  5. Connect the client to the network and boot QEMU with the target disk attached to the virtual machine.

    $ qemu -boot n -hda target_disk -m 4096
    

    Note

    QEMU bridged networking

    In order to let qemu connect to the network we recommend to setup a network bridge on the host system and let qemu connect to it via a custom /etc/qemu-ifup. For details see https://en.wikibooks.org/wiki/QEMU/Networking