Clear Linux* OS on KVM

This page explains how to run Clear Linux* OS in a virtualized environment using KVM.

Install QEMU-KVM

  1. Enable the Intel® Virtualization Technology (Intel® VT) and the Intel® Virtualization Technology for Directed I/O (Intel® VT-d) in the host machine’s BIOS.

  2. Log in and open a terminal emulator.

  3. Install QEMU*-KVM on the host machine. Below are some examples using different distros:

    Host OS

    Installation command

    Clear Linux OS

    sudo swupd bundle-add kvm-host

    Ubuntu* and Mint*

    sudo apt-get install qemu-kvm


    dnf install qemu-kvm

Download and launch the virtual machine image

  1. Download the latest pre-built Clear Linux OS KVM image file from the image directory. Look for clear-<version>-kvm.img.xz. You can also use this command:

    curl -o clear.img.xz$(curl | grep -o clear-'[0-9]'*-kvm.img.xz | head -1)
  2. Uncompress the downloaded image:

    xz -dv clear.img.xz
  3. Download the 3 OVMF files (OVMF.fd, OVMF_CODE.fd, OVMF_VARS.fd) that provides UEFI support for virtual machines.

    curl -O
    curl -O
    curl -O


    The default OVMF files from Clear Linux OS may not work for some non-Clear Linux OS distro version(s). You may get an ASSERT in the debug.log file when starting the VM. If you encounter this, use the distro-specific OVMF files instead.

  4. Download the script from the image directory. This script will launch the Clear Linux OS VM and provide console interaction within the same terminal emulator window.

    curl -O
  5. Start the Clear Linux OS KVM virtual machine:

    sudo bash ./ clear.img
  6. Log in as root user and set a new password.

Optional: Enable SSH access

To interact with the Clear Linux OS VM remotely through SSH instead of the console it was launched from, follow these steps.

  1. Enable and configure SSH in the Clear Linux OS VM to allow root login as described in Enable and configure SSH service.

  2. SSH into the Clear Linux OS VM using the port 10022. This port number is set in and passed through to the SSH service running on port 22

    ssh -p 10022 root@<ip-addr-of-kvm-host>

Optional: Install a graphical user interface (GUI)

To add GDM to the Clear Linux OS VM, follow these steps:

  1. Shutdown the active Clear Linux OS VM.

  2. Install the Spice viewer on the localhost or remote system. Below are some examples using different distros:

    Host OS

    Installation command

    Clear Linux OS

    sudo swupd bundle-add virt-viewer

    Ubuntu* and Mint*

    sudo apt-get install virt-viewer


    dnf install virt-viewer

  3. Modify the script to increase memory (-m), add graphics driver (-vga), and add Spice (-spice, -usb, and -device) support.

    qemu-system-x86_64 \
        -enable-kvm \
        ${UEFI_BIOS} \
        -smp sockets=1,cpus=4,cores=2 -cpu host \
        -m 4096 \
        -vga qxl \
        -nographic \
        -spice port=5924,disable-ticketing \
        -usb \
        -device usb-tablet,bus=usb-bus.0 \
        -drive file="$IMAGE",if=virtio,aio=threads,format=raw \
        -netdev user,id=mynet0,hostfwd=tcp::${VMN}0022-:22,hostfwd=tcp::${VMN}2375-:2375 \
        -device virtio-net-pci,netdev=mynet0 \
        -debugcon file:debug.log -global isa-debugcon.iobase=0x402 $@
  4. Due to changes in the script from the previous step, having previously used OVMF files will result in the VM not booting properly and you returning to the UEFI shell. The easiest way to avoid this is to delete the 3 OVMF files and reobtain originals before relaunching the VM:

    rm -v OVMF*.fd
    curl -O
    curl -O
    curl -O
  5. Increase the size of the VM by 10GB to accommodate the GDM installation:

    qemu-img resize -f raw clear-<version>-kvm.img +10G
  6. Relaunch the Clear Linux OS VM:

    sudo ./ clear.img
  7. Determine the IP address of the host on which you will launch the VM. Substitute <ip-addr-of-kvm-host> in the next step with this information.

    ip a
  8. From the local host or remote system, open a new terminal emulator window and connect into the Clear Linux OS VM using the Spice viewer:

    remote-viewer spice://<ip-address-of-kvm-host>:5924
  9. Log in as root user into the Clear Linux OS VM.

  10. Follow these steps from Increase Virtual Disk Size of an Image to resize the partition of the virtual disk of the VM.

  11. Add GDM to the Clear Linux OS VM:

    swupd bundle-add desktop-autostart
  12. Reboot the Clear Linux OS VM to start GDM:

  13. Go through the GDM out-of-box experience (OOBE).

  14. The default aspect ratio of the GDM GUI for the Clear Linux OS VM is 4:3. To change it, use GDM’s Devices > Displays setting tool (located at the top-right corner).

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