OpenVMM Troubleshooting

This page includes a miscellaneous collection of troubleshooting tips for common issues you may encounter when running OpenVMM.

If you are still running into issues, consider filing an issue on the OpenVMM GitHub Issue tracker.

failed to open /dev/kvm/

Error:

fatal error: failed to launch vm worker

Caused by:
    0: failed to launch worker
    1: failed to create the prototype partition
    2: kvm error
    3: failed to open /dev/kvm
    4: Permission denied (os error 13)

Solution:

When launching from a Linux/WSL host, your user account will need permission to interact with /dev/kvm.

For example, you could add yourself to the group that owns that file:

sudo usermod -a -G <group> <username>

For this change to take effect, you may need to restart. If using WSL2, you can simply restart WSL2 (run wsl --shutdown from Powershell and reopen the WSL window).

Alternatively, for a quick-and-dirty solution that will only persist for the duration of the current user session:

sudo chown <username> /dev/kvm