vfkit: Use EFI booloader (#20833)

* vfkit: Log serial console to file

To make debugging easier, add virtio-serial device logging serial
console to file:

    ~/.minikube/machines/NAME/serial.log

To enable logging, we need to enable the console in the kernel command
line, since we still use direct kernel boot.

Example log:

    % cat /Users/nir/.minikube/machines/vfkit/vfkig.log
    [    0.896094] cacheinfo: Unable to detect cache hierarchy for CPU 0
    [    0.897186] loop: module loaded
    [    0.897670] virtio_blk virtio2: [vda] 840488 512-byte logical blocks (430 MB/410 MiB)
    [    0.897733] vda: detected capacity change from 0 to 430329856
    [    0.898460] virtio_blk virtio3: [vdb] 40960000 512-byte logical blocks (21.0 GB/19.5 GiB)
    [    0.898533] vdb: detected capacity change from 0 to 20971520000
    ...
    [    1.794714] systemd[1]: Detected virtualization vm-other.
    [    1.794752] systemd[1]: Detected architecture arm64.

    Welcome to Buildroot 2025.02!

    [    1.794944] systemd[1]: Hostname set to <minikube>.
    [    1.795011] systemd[1]: Initializing machine ID from random generator.
    ...
    [  OK  ] Started Container Runtime Interface for OCI (CRI-O).
    [  OK  ] Reached target Multi-User System.

    Welcome to minikube
    vfkit login: [    6.681578] systemd-ssh-generator[630]: Binding SSH to AF_UNIX socket /run/ssh-unix-local/socket.

* vfkit: Use EFI bootloader

With the fixed iso, we can simplify the driver using the EFI bootloader
option[1] instead of the legacy and deprecated --kernel, --kernel-cmdline,
and --initrd options[2].

Example run:

    % minikube start -p vfkit --driver vfkit --container-runtime containerd --network vmnet-shared
    😄  [vfkit] minikube v1.36.0 on Darwin 15.5 (arm64)
    ✨  Using the vfkit driver based on user configuration
    👍  Starting "vfkit" primary control-plane node in "vfkit" cluster
    🔥  Creating vfkit VM (CPUs=2, Memory=6000MB, Disk=20000MB) ...
    📦  Preparing Kubernetes v1.33.1 on containerd 1.7.23 ...
        ▪ Generating certificates and keys ...
        ▪ Booting up control plane ...
        ▪ Configuring RBAC rules ...
    🔗  Configuring bridge CNI (Container Networking Interface) ...
    🔎  Verifying Kubernetes components...
        ▪ Using image gcr.io/k8s-minikube/storage-provisioner:v5
    🌟  Enabled addons: default-storageclass, storage-provisioner
    🏄  Done! kubectl is now configured to use "vfkit" cluster and "default" namespace by default

Comparing direct kernel boot and --bootloader efi shows that it is little bit faster and boot time is more consistent.

    % hyperfine -r 10 -C "minikube delete" \
        "vfkit-efi/out/minikube start --driver vfkit --network vmnet-shared --container-runtime containerd --no-kubernetes" \
        "vfkit-direct/out/minikube start --driver vfkit --network vmnet-shared --container-runtime containerd --no-kubernetes"
    Benchmark 1: vfkit-efi/out/minikube start --driver vfkit --network vmnet-shared --container-runtime containerd --no-kubernetes
      Time (mean ± σ):     10.205 s ±  0.656 s    [User: 0.381 s, System: 0.266 s]
      Range (min … max):    9.106 s … 11.254 s    10 runs

    Benchmark 2: vfkit-direct/out/minikube start --driver vfkit --network vmnet-shared --container-runtime containerd --no-kubernetes
      Time (mean ± σ):     10.933 s ±  1.616 s    [User: 0.402 s, System: 0.406 s]
      Range (min … max):    9.155 s … 14.168 s    10 runs

    Summary
      vfkit-efi/out/minikube start --driver vfkit --network vmnet-shared --container-runtime containerd --no-kubernetes ran
        1.07 ± 0.17 times faster than vfkit-direct/out/minikube start --driver vfkit --network vmnet-shared --container-runtime containerd --no-kubernetes

[1] https://github.com/crc-org/vfkit/blob/main/doc/usage.md#efi-bootloader
[2] https://github.com/crc-org/vfkit/blob/main/doc/usage.md#deprecated-options

* docs: Update vfkit driver documentation

- Separate vfkit requirements and vmnet-shared requirements
- Update minimal macOS version required for --bootloader efi
- Simplify vfkit upgrade, it is available in brew now

pkg/drivers/vfkit/vfkit.go

@@ -56,6 +56,8 @@ const (
 	isoFilename     = "boot2docker.iso"
 	pidFileName     = "vfkit.pid"
 	sockFilename    = "vfkit.sock"
+	serialFileName  = "serial.log"
+	efiVarsFileName = "vfkit.efivars"
 	defaultSSHUser  = "docker"
 )
 
@@ -67,7 +69,6 @@ type Driver struct {
 	DiskSize       int
 	CPU            int
 	Memory         int
-	Cmdline        string
 	ExtraDisks     int
 	Network        string        // "", "nat", "vmnet-shared"
 	MACAddress     string        // For network=nat, network=""
@@ -189,12 +190,6 @@ func (d *Driver) Create() error {
 	if err := b2dutils.CopyIsoToMachineDir(d.Boot2DockerURL, d.MachineName); err != nil {
 		return err
 	}
-	isoPath := d.ResolveStorePath(isoFilename)
-
-	log.Info("Extracting Kernel...")
-	if err := d.extractKernel(isoPath); err != nil {
-		return err
-	}
 
 	log.Info("Creating SSH key...")
 	if err := ssh.GenerateSSHKey(d.sshKeyPath()); err != nil {
@@ -256,9 +251,10 @@ func (d *Driver) startVfkit(socketPath string) error {
 		"--memory", fmt.Sprintf("%d", d.Memory),
 		"--cpus", fmt.Sprintf("%d", d.CPU),
 		"--restful-uri", fmt.Sprintf("unix://%s", d.sockfilePath()))
-	var isoPath = filepath.Join(machineDir, isoFilename)
+
+	efiVarsPath := d.ResolveStorePath(efiVarsFileName)
 	startCmd = append(startCmd,
-		"--device", fmt.Sprintf("virtio-blk,path=%s", isoPath))
+		"--bootloader", fmt.Sprintf("efi,variable-store=%s,create", efiVarsPath))
 
 	if socketPath != "" {
 		// The guest will be able to access other guests in the vmnet network.
@@ -273,20 +269,21 @@ func (d *Driver) startVfkit(socketPath string) error {
 	startCmd = append(startCmd,
 		"--device", "virtio-rng")
 
+	var isoPath = filepath.Join(machineDir, isoFilename)
 	startCmd = append(startCmd,
-		"--kernel", d.ResolveStorePath("bzimage"))
+		"--device", fmt.Sprintf("virtio-blk,path=%s", isoPath))
+
 	startCmd = append(startCmd,
-		"--kernel-cmdline", d.Cmdline)
+		"--device", fmt.Sprintf("virtio-blk,path=%s", d.diskPath()))
-	startCmd = append(startCmd,
-		"--initrd", d.ResolveStorePath("initrd"))
 
 	for i := 0; i < d.ExtraDisks; i++ {
 		startCmd = append(startCmd,
 			"--device", fmt.Sprintf("virtio-blk,path=%s", pkgdrivers.ExtraDiskPath(d.BaseDriver, i)))
 	}
 
+	serialPath := d.ResolveStorePath(serialFileName)
 	startCmd = append(startCmd,
-		"--device", fmt.Sprintf("virtio-blk,path=%s", d.diskPath()))
+		"--device", fmt.Sprintf("virtio-serial,logFilePath=%s", serialPath))
 
 	log.Debugf("executing: vfkit %s", strings.Join(startCmd, " "))
 	os.Remove(d.sockfilePath())
@@ -410,22 +407,6 @@ func (d *Driver) Restart() error {
 	return d.Start()
 }
 
-func (d *Driver) extractKernel(isoPath string) error {
-	for _, f := range []struct {
-		pathInIso string
-		destPath  string
-	}{
-		{"/boot/bzimage", "bzimage"},
-		{"/boot/initrd", "initrd"},
-	} {
-		fullDestPath := d.ResolveStorePath(f.destPath)
-		if err := pkgdrivers.ExtractFile(isoPath, f.pathInIso, fullDestPath); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
 func (d *Driver) killVfkit() error {
 	if err := d.SetVFKitState("HardStop"); err != nil {
 		// Typically fails with EOF due to https://github.com/crc-org/vfkit/issues/277.

pkg/minikube/registry/drvs/vfkit/vfkit.go

@@ -98,7 +98,6 @@ func configure(cfg config.ClusterConfig, n config.Node) (interface{}, error) {
 		DiskSize:       cfg.DiskSize,
 		Memory:         cfg.Memory,
 		CPU:            cfg.CPUs,
-		Cmdline:        "",
 		ExtraDisks:     cfg.ExtraDisks,
 		Network:        cfg.Network,
 		MACAddress:     mac,

site/content/en/docs/drivers/vfkit.md

@@ -11,6 +11,11 @@ aliases:
 macOS virtualization, optimized for lightweight virtual machines and
 container deployment.
 
+## Requirements
+
+- Requires macOS 13 or later.
+- Requires minikube version 1.36.0 or later.
+
 ## Networking
 
 The vfkit driver has two networking options: `nat` and `vmnet-shared`.
@@ -25,8 +30,6 @@ installation instructions bellow.
 
 ### Requirements
 
-- Requires macOS 10.15 or later
-- Requires minikube version 1.36.0 or later.
 - Requires [vmnet-helper](https://github.com/nirs/vmnet-helper).
 
 ### Install vment-helper
@@ -94,13 +97,10 @@ Run `minikube start --driver vfkit --alsologtostderr -v=7` to debug crashes
 
 ### Upgrade VFKit
 
-New updates to macOS often require an updated vfkit driver. To upgrade:
+```shell
-
+brew update
-* If Podman Desktop is installed, it also bundles `vfkit`
+brew upgrade vfkit
-* If you have Brew Package Manager, run: `brew upgrade vfkit`
+```
-* As a final alternative, you install the latest VFKit from [GitHub](https://github.com/crc-org/vfkit/releases)
-* To check your current version, run: `vfkit -v`
-* If the version didn't change after upgrading verify the correct VFKit is in the path. run: `which vfkit`
 
 ### Troubleshooting the vmnet-shared network