Wednesday, March 24, 2021

Installing Red Hat OpenShift on KVM on Z

While there is no documentation on how to install Red Hat OCP on Linux on Z with a static IP under KVM today, the instructions here will get you almost there. However, there are a few parts within section Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines that require attention. Here is an updated version that will get you through:
 
4. You can use an empty QCOW2 image: Using the prepared one will also work, but it will be overwritten anyway.

5. Start the guest with the following modified command-line:
  $ virt-install --noautoconsole
     --boot kernel=/bootkvm/rhcos-4.7.0-s390x-live-kernel-s390x, \
       initrd=/bootkvm/rhcos-4.7.0-s390x-live-initramfs.s390x.img, \
           kernel_args='rd.neednet=1 dfltcc=off coreos.inst.install_dev=/dev/vda
       coreos.live.rootfs_url=https://mirror.openshift.com \
           /pub/openshift-v4/s390x/dependencies/rhcos/4.7/4.7.0 \
           /rhcos-4.7.0-s390x-live-rootfs.s390x.img
       coreos.inst.ignition_url=http://
192.168.5.106:8080/ignition \
       /bootstrap.ign ip=192.168.5.11::
192.168.5.1:24:bootstrap-0.pok-241-macvtap- \
           mars.com::none
       nameserver=9.1.1.1'
     --connect qemu:///system
     --name bootstrap-0
     --memory 16384
     --vcpus 8
     --disk /home/libvirt/images/bootstrap-0.qcow2
     --accelerate
     --import
     --network network=macvtap-mv1
     --qemu-commandline="-drive if=none,id=ignition,format=raw,file=/bootkvm \
           /bootstrap.ign,readonly=on -device virtio-blk, \
           serial=ignition,drive=ignition"

Note the following changes:

  • Use the live installer kernel, initrd (you can get them from the redhat mirror) and parmline (this you need to create yourself once for each guest) in the --boot parameter. This is basically like installing on z/VM, and will write the image to your QCOW2 image with the correct static IP configuration. Keep in mind that the ignition file needs to be provided by an http/s server for this method to work
  • dfltcc=off is required for IBM z15 and LinuxONE III

6. To restart the guest later on, you will need to change the guest definition to boot from the QCOW2 image.
When the kernel parms are passed into the installer, the domain xml will look like this once the guest is installed and running:
  <os>
    <type arch='s390x' machine='s390-ccw-virtio-rhel8.2.0'>hvm</type>
    <kernel>/bootkvm/rhcos-4.7.0-s390x-live-kernel-s390x</kernel>
    <initrd>/bootkvm/rhcos-4.7.0-s390x-live-initramfs.s390x.img</initrd>
    <cmdline>rd.neednet=1 dfltcc=off coreos.inst.install_dev=/dev/vda
        coreos.live.rootfs_url=https://mirror.openshift.com/pub/openshift-v4/ \
             s390x/dependencies/rhcos/4.7/4.7.0/rhcos-4.7.0-s390x-live- \
             rootfs.s390x.img
        coreos.inst.ignition_url=http://
192.168.5.106:8080/ignition/worker.ign
        ip=
192.168.5.49::192.168.5.1:24:worker-1.pok-241-macvtap- \
             mars.com::none nameserver=1.1.1.1</cmdline>
    <boot dev='hd'/>
  </os>

However, this domain XML still points at the installation media, hence a reboot will not work (it will merely restart the installation).
Remove the <kernel>, <initrd>, <cmdline> elements, so that all that is left is the following:
  <os>
    <type arch='s390x' machine='s390-ccw-virtio-rhel8.2.0'>hvm</type>
    <boot dev='hd'/>
  </os>

With this, the guest will start successfully.

 [Content contributed by Alexander Klein]

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