Add krunkit driver supporting GPU acceleration on macOS (#20826)

* krunkit: Add krunkit driver

krunkit is a tool to launch configurable virtual machines using the
libkrun platform, optimized for GPU accelerated virtual machines and AI
workloads on Apple silicon.

It is mostly compatible with vfkit; the driver is a simplified copy of
the vfkit driver. Unlike vfkit, krunkit is available only on Apple
silicon.

Changes compared to vfkit driver:
- krunkit requires unix socket for networking, so we must use
  vment-helper.
- krunkit does not support HardStop, so we kill it using SIGKILL.
- We must enable vmnet offloading, required for krunkit.
- The code was simplified since vmnet-helper is always used
- Code was cleaned up to use .ResolveStorePath()
- Unused Upgrade() function was removed
- Types and functions that should not be public made private

We require krunkit 0.2.2, supporting --restul-uri=unix://.

* reason: Make vment-helper error driver agnostic

Previously it was used only for vfkit, so we suggested to fallback to
the `nat` network. This advice is not relevant to krunkit or to qemu
(which can also use vmnet-helper).

Change the error to recommend installing vment-helper. We need to think
how we can recommend other networks for vfkit and qemu. Another solution
is to create error for every driver+network combination but this seems
hard to manage.

* hack: Add krunkit integration test

This is the same way that we test vfkit. This test is not running in the
CI.

Issues:
- Need to install and configure vment-helper (requires root).

* site: Add krunkit driver documentation

Author: nirs

cmd/minikube/cmd/start_flags.go

@@ -201,7 +201,7 @@ func initMinikubeFlags() {
 	startCmd.Flags().String(network, "", "network to run minikube with. Used by docker/podman, qemu, kvm, and vfkit drivers. If left empty, minikube will create a new network.")
 	startCmd.Flags().StringVarP(&outputFormat, "output", "o", "text", "Format to print stdout in. Options include: [text,json]")
 	startCmd.Flags().String(trace, "", "Send trace events. Options include: [gcp]")
-	startCmd.Flags().Int(extraDisks, 0, "Number of extra disks created and attached to the minikube VM (currently only implemented for hyperkit, kvm2, qemu2, and vfkit drivers)")
+	startCmd.Flags().Int(extraDisks, 0, "Number of extra disks created and attached to the minikube VM (currently only implemented for hyperkit, kvm2, qemu2, vfkit, and krunkit drivers)")
 	startCmd.Flags().Duration(certExpiration, constants.DefaultCertExpiration, "Duration until minikube certificate expiration, defaults to three years (26280h).")
 	startCmd.Flags().String(binaryMirror, "", "Location to fetch kubectl, kubelet, & kubeadm binaries from.")
 	startCmd.Flags().Bool(disableOptimizations, false, "If set, disables optimizations that are set for local Kubernetes. Including decreasing CoreDNS replicas from 2 to 1. Defaults to false.")
@@ -1011,7 +1011,7 @@ func interpretWaitFlag(cmd cobra.Command) map[string]bool {
 }
 
 func checkExtraDiskOptions(cmd *cobra.Command, driverName string) {
-	supportedDrivers := []string{driver.HyperKit, driver.KVM2, driver.QEMU2, driver.VFKit}
+	supportedDrivers := []string{driver.HyperKit, driver.KVM2, driver.QEMU2, driver.VFKit, driver.Krunkit}
 
 	if cmd.Flags().Changed(extraDisks) {
 		supported := false

hack/jenkins/common.sh

@@ -145,6 +145,9 @@ case "${DRIVER}" in
   vfkit)
     echo "vfkit:     $(vfkit --version)"
   ;;
+  krunkit)
+    echo "krunkit:   $(krunkit --version)"
+  ;;
 esac
 
 echo ""

hack/jenkins/osx_integration_tests_krunkit.sh

@@ -0,0 +1,39 @@
+#!/bin/bash
+
+# Copyright 2024 The Kubernetes Authors All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# This script runs the integration tests on an OSX machine for the Hyperkit Driver
+
+# The script expects the following env variables:
+# MINIKUBE_LOCATION: GIT_COMMIT from upstream build.
+# COMMIT: Actual commit ID from upstream build
+# EXTRA_BUILD_ARGS (optional): Extra args to be passed into the minikube integrations tests
+# access_token: The GitHub API access token. Injected by the Jenkins credential provider.
+
+
+set -ex
+
+ARCH="arm64"
+OS="darwin"
+DRIVER="krunkit"
+JOB_NAME="Krunkit_macOS"
+EXTRA_TEST_ARGS=""
+EXTERNAL="yes"
+
+brew tap slp/krunkit
+brew install krunkit
+
+source common.sh