krunkit
Overview
krunkit is an open-source program for macOS virtualization, optimized for GPU accelerated virtual machines and AI workloads.
Requirements
- Available only on Apple silicon.
- Requires macOS 14 or later.
- Requires minikube version 1.37.0 or later.
- Requires krunkit version 1.0.0 or later.
- Requires vmnet-helper.
Installing krunkit
To install krunkit run:
brew tap libkrun/krun
brew trust libkrun/krun # trust the tap only required if using Homebrew 6.0 or later
brew install krunkit
Note
If you’ve ever installed krunkit from the old tapslp/krunkit or slp/krun, to upgrade to the latest version you’ll need to follow the Removing the old Homebrew tap instructions first before installing as shown above.
Networking
To use the krunkit driver you must install vmnet-helper, see installation instructions below.
Install vmnet-helper
On macOS 26 or later, install vmnet-helper using Homebrew:
brew tap nirs/vmnet-helper
brew trust nirs/vmnet-helper
brew install vmnet-helper
On macOS 15 or earlier, install the latest version using the install script:
curl -fsSL https://github.com/minikube-machine/vmnet-helper/releases/latest/download/install.sh | bash
The command downloads the latest release from GitHub and installs it to
/opt/vmnet-helper, and configures a sudoers rule to allow running
vmnet-helper without a password.
Grant permission to run vmnet-helper manually on macOS 15 or earlier
On macOS 15 or earlier, vmnet-helper must run as root to create a vmnet interface. To let users in the staff group run it without a password, install the default sudoers rule. The install script offers to add this automatically; if you declined, run the command below manually:
sudo install -m 0640 /opt/vmnet-helper/share/doc/vmnet-helper/sudoers.d/vmnet-helper /etc/sudoers.d/
You can change the sudoers configuration to allow access to specific users or other groups.
IMPORTANT: On macOS 15 or earlier, the vmnet-helper executable and the directory where it is installed must be owned by root and may not be modifiable by unprivileged users.
Usage
minikube start --driver krunkit
Vmnet offloading
The --vmnet-offloading flag enables vmnet checksum and TSO offloading,
which can improve host network throughput by up to 5x (e.g. pulling images
from a local registry, RBD mirroring):
minikube start --driver krunkit --vmnet-offloading
Warning
Offloading may not work for all workloads. Review the limitations below and verify that this flag works for your workload before relying on it.Limitations
- All VMs connected to the same vmnet bridge must enable offloading. If any VM on the bridge does not use offloading, the bridge disables TSO and TX performance drops significantly.
- Pod-to-VM network RX performance is severely degraded when offloading is enabled, making it almost unusable. Pod-to-host network works well and is faster than without offloading.
Issues
Other
Troubleshooting
Run with logs
Run minikube start --driver krunkit --alsologtostderr -v=7 to debug crashes
Troubleshooting vmnet-helper
Check for errors in vmnet-helper log:
$MINIKUBE_HOME/.minikube/machines/MACHINE-NAME/vmnet-helper.log
Check that the vmnet-helper process is running:
ps au | grep vmnet-helper | grep -v grep
If the helper is not running restart the minikube cluster.
For help with vmnet-helper please use the discussions.
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