Merge pull request #209 from lstocchi/i124

ignition: add support for ignition config file

cmd/vfkit/main.go

@@ -21,6 +21,9 @@ package main
 
 import (
 	"fmt"
+	"io"
+	"net"
+	"net/http"
 	"os"
 	"os/signal"
 	"runtime"
@@ -86,6 +89,10 @@ func newVMConfiguration(opts *cmdline.Options) (*config.VirtualMachine, error) {
 		return nil, err
 	}
 
+	if err := vmConfig.AddIgnitionFileFromCmdLine(opts.IgnitionPath); err != nil {
+		return nil, fmt.Errorf("failed to add ignition file: %w", err)
+	}
+
 	return vmConfig, nil
 }
 
@@ -137,6 +144,21 @@ func runVFKit(vmConfig *config.VirtualMachine, opts *cmdline.Options) error {
 }
 
 func runVirtualMachine(vmConfig *config.VirtualMachine, vm *vf.VirtualMachine) error {
+	if vm.Config().Ignition != nil {
+		go func() {
+			file, err := os.Open(vmConfig.Ignition.ConfigPath)
+			if err != nil {
+				log.Error(err)
+			}
+			defer file.Close()
+			reader := file
+			if err := startIgnitionProvisionerServer(reader, vmConfig.Ignition.SocketPath); err != nil {
+				log.Error(err)
+			}
+			log.Debug("ignition vsock server exited")
+		}()
+	}
+
 	if err := vm.Start(); err != nil {
 		return err
 	}
@@ -198,3 +220,33 @@ func runVirtualMachine(vmConfig *config.VirtualMachine, vm *vf.VirtualMachine) e
 
 	return <-errCh
 }
+
+func startIgnitionProvisionerServer(ignitionReader io.Reader, ignitionSocketPath string) error {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/", func(w http.ResponseWriter, _ *http.Request) {
+		_, err := io.Copy(w, ignitionReader)
+		if err != nil {
+			log.Errorf("failed to serve ignition file: %v", err)
+		}
+	})
+
+	listener, err := net.Listen("unix", ignitionSocketPath)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		if err := listener.Close(); err != nil {
+			log.Error(err)
+		}
+	}()
+
+	srv := &http.Server{
+		Handler:           mux,
+		Addr:              ignitionSocketPath,
+		ReadHeaderTimeout: 10 * time.Second,
+		IdleTimeout:       60 * time.Second,
+	}
+
+	log.Debugf("ignition socket: %s", ignitionSocketPath)
+	return srv.Serve(listener)
+}

cmd/vfkit/main_test.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"bytes"
+	"io"
+	"net"
+	"net/http"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestStartIgnitionProvisionerServer(t *testing.T) {
+	socketPath := "virtiovsock"
+	defer os.Remove(socketPath)
+
+	ignitionData := []byte("ignition configuration")
+	ignitionReader := bytes.NewReader(ignitionData)
+
+	// Start the server using the socket so that it can returns the ignition data
+	go func() {
+		err := startIgnitionProvisionerServer(ignitionReader, socketPath)
+		require.NoError(t, err)
+	}()
+
+	// Make a request to the server
+	client := http.Client{
+		Transport: &http.Transport{
+			Dial: func(_, _ string) (net.Conn, error) {
+				return net.Dial("unix", socketPath)
+			},
+		},
+	}
+	resp, err := client.Get("http://unix://" + socketPath)
+	require.NoError(t, err)
+	defer resp.Body.Close()
+
+	// Verify the response from the server is actually the ignition data
+	body, err := io.ReadAll(resp.Body)
+	require.NoError(t, err)
+	assert.Equal(t, ignitionData, body)
+}

contrib/ignition/README.md

@@ -0,0 +1,9 @@
+## Ignition
+
+Ignition uses a JSON configuration file to define the desired changes. The format of this config is specified in detail [here](https://coreos.github.io/ignition/specs/), and its [MIME type](http://www.iana.org/assignments/media-types/application/vnd.coreos.ignition+json) is registered with IANA.
+
+`myconfig.json` file provides an example of configuration that adds a new `testuser`, creates a new file to `/etc/myapp` with the content listed in the same `files` section and add a systemd unit drop-in to modify the existing service `systemd-journald` and sets its environment variable SYSTEMD_LOG_LEVEL to debug.
+
+### Examples
+
+More examples can be found at https://coreos.github.io/ignition/examples/

contrib/ignition/myconfig.json

@@ -0,0 +1,31 @@
+{
+  "ignition": {
+    "version": "3.0.0"
+  },
+  "passwd": {
+    "users": [
+      {
+        "name": "testuser",
+        "sshAuthorizedKeys": [
+          "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIO43Z9aRPvvj1zMib/Hh4oWX+MuOPXdFChFMaWfishLj"
+        ]
+      }
+    ]
+  },
+  "storage": {
+    "files": [{
+      "path": "/etc/someconfig",
+      "mode": 420,
+      "contents": { "source": "data:,example%20file%0A" }
+    }]
+  },
+  "systemd": {
+    "units": [{
+      "name": "systemd-journald.service",
+      "dropins": [{
+        "name": "debug.conf",
+        "contents": "[Service]\nEnvironment=SYSTEMD_LOG_LEVEL=debug"
+      }]
+    }]
+  }
+}

doc/usage.md

@@ -461,3 +461,18 @@ Proper use of this flag may look similar to the following section of a command:
 ```bash
 --device virtio-input,keyboard --device virtio-input,pointing --device virtio-gpu,width=1920,height=1080 --gui
 ```
+
+### Ignition
+
+#### Description
+
+The `--ignition` option allows you to specify a configuration file for Ignition. Vfkit will open a vsock connection between the host and the guest and start a lightweight HTTP server to push the configuration file to Ignition.
+
+You can find example configurations and more details about Ignition at https://coreos.github.io/ignition/ 
+
+#### Example
+
+This command provisions the configuration file to Ignition on the guest
+```
+--ignition configuration-path
+```

pkg/cmdline/cmdline.go

@@ -23,6 +23,8 @@ type Options struct {
 	LogLevel string
 
 	UseGUI bool
+
+	IgnitionPath string
 }
 
 const DefaultRestfulURI = "none://"
@@ -50,4 +52,6 @@ func AddFlags(cmd *cobra.Command, opts *Options) {
 	cmd.Flags().StringVar(&opts.LogLevel, "log-level", "", "set log level")
 	cmd.Flags().StringVar(&opts.RestfulURI, "restful-uri", DefaultRestfulURI, "URI address for RESTful services")
 
+	cmd.Flags().StringVar(&opts.IgnitionPath, "ignition", "", "path to the ignition file")
+
 }

pkg/config/config.go

@@ -16,6 +16,7 @@ import (
 	"math"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"strconv"
 	"strings"
 
@@ -30,6 +31,7 @@ type VirtualMachine struct {
 	Bootloader Bootloader     `json:"bootloader"`
 	Devices    []VirtioDevice `json:"devices,omitempty"`
 	Timesync   *TimeSync      `json:"timesync,omitempty"`
+	Ignition   *Ignition      `json:"ignition,omitempty"`
 }
 
 // TimeSync enables synchronization of the host time to the linux guest after the host was suspended.
@@ -38,13 +40,23 @@ type TimeSync struct {
 	VsockPort uint32 `json:"vsockPort"`
 }
 
+type Ignition struct {
+	ConfigPath string `json:"configPath"`
+	SocketPath string `json:"socketPath"`
+}
+
 // The VMComponent interface represents a VM element (device, bootloader, ...)
 // which can be converted from/to commandline parameters
 type VMComponent interface {
 	FromOptions([]option) error
 	ToCmdLine() ([]string, error)
 }
 
+const (
+	ignitionVsockPort  uint   = 1024
+	ignitionSocketName string = "ignition.sock"
+)
+
 // NewVirtualMachine creates a new VirtualMachine instance. The virtual machine
 // will use vcpus virtual CPUs and it will be allocated memoryMiB mibibytes
 // (1024*1024 bytes) of RAM. bootloader specifies how the virtual machine will
@@ -96,6 +108,10 @@ func (vm *VirtualMachine) ToCmdLine() ([]string, error) {
 		args = append(args, devArgs...)
 	}
 
+	if vm.Ignition != nil {
+		args = append(args, "--ignition", vm.Ignition.ConfigPath)
+	}
+
 	return args, nil
 }
 
@@ -191,6 +207,39 @@ func (vm *VirtualMachine) TimeSync() *TimeSync {
 	return vm.Timesync
 }
 
+func IgnitionNew(configPath string, socketPath string) (*Ignition, error) {
+	if configPath == "" || socketPath == "" {
+		return nil, fmt.Errorf("config path and socket path cannot be empty")
+	}
+	return &Ignition{
+		ConfigPath: configPath,
+		SocketPath: socketPath,
+	}, nil
+}
+
+func (vm *VirtualMachine) AddIgnitionFileFromCmdLine(cmdlineOpts string) error {
+	if cmdlineOpts == "" {
+		return nil
+	}
+	opts := strings.Split(cmdlineOpts, ",")
+	if len(opts) != 1 {
+		return fmt.Errorf("ignition only accept one option in command line argument")
+	}
+
+	socketPath := filepath.Join(os.TempDir(), ignitionSocketName)
+	dev, err := VirtioVsockNew(ignitionVsockPort, socketPath, true)
+	if err != nil {
+		return err
+	}
+	vm.Devices = append(vm.Devices, dev)
+	ignition, err := IgnitionNew(opts[0], socketPath)
+	if err != nil {
+		return err
+	}
+	vm.Ignition = ignition
+	return nil
+}
+
 func TimeSyncNew(vsockPort uint) (VMComponent, error) {
 
 	if vsockPort > math.MaxUint32 {

pkg/config/config_test.go

@@ -0,0 +1,23 @@
+package config
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestAddIgnitionFile_MultipleOptions(t *testing.T) {
+	vm := &VirtualMachine{}
+	err := vm.AddIgnitionFileFromCmdLine("file1,file2")
+	assert.EqualError(t, err, "ignition only accept one option in command line argument")
+}
+
+func TestAddIgnitionFile_OneOption(t *testing.T) {
+	vm := &VirtualMachine{}
+	err := vm.AddIgnitionFileFromCmdLine("file1")
+	require.NoError(t, err)
+	assert.Len(t, vm.Devices, 1)
+	assert.Equal(t, uint32(ignitionVsockPort), vm.Devices[0].(*VirtioVsock).Port)
+	assert.Equal(t, "file1", vm.Ignition.ConfigPath)
+}

pkg/config/json.go

@@ -28,6 +28,7 @@ const (
 	usbMassStorage vmComponentKind = "usbmassstorage"
 	nvme           vmComponentKind = "nvme"
 	rosetta        vmComponentKind = "rosetta"
+	ignition       vmComponentKind = "ignition"
 )
 
 type jsonKind struct {
@@ -89,6 +90,17 @@ func unmarshalDevices(rawMsg json.RawMessage) ([]VirtioDevice, error) {
 	return devices, nil
 }
 
+func unmarshalIgnition(rawMsg json.RawMessage) (Ignition, error) {
+	var ignition Ignition
+
+	err := json.Unmarshal(rawMsg, &ignition)
+	if err != nil {
+		return Ignition{}, err
+	}
+
+	return ignition, nil
+}
+
 // VirtioNet needs a custom unmarshaller as net.HardwareAddress is not
 // serialized/unserialized in its expected format, instead of
 // '00:11:22:33:44:55', it's serialized as base64-encoded raw bytes such as
@@ -208,6 +220,11 @@ func (vm *VirtualMachine) UnmarshalJSON(b []byte) error {
 			if err == nil {
 				vm.Devices = devices
 			}
+		case "ignition":
+			ignition, err := unmarshalIgnition(*rawMsg)
+			if err == nil {
+				vm.Ignition = &ignition
+			}
 		}
 
 		if err != nil {
@@ -367,3 +384,14 @@ func (dev *USBMassStorage) MarshalJSON() ([]byte, error) {
 		USBMassStorage: *dev,
 	})
 }
+
+func (ign *Ignition) MarshalJSON() ([]byte, error) {
+	type devWithKind struct {
+		jsonKind
+		Ignition
+	}
+	return json.Marshal(devWithKind{
+		jsonKind: kind(ignition),
+		Ignition: *ign,
+	})
+}

pkg/config/json_test.go

@@ -85,6 +85,16 @@ var jsonTests = map[string]jsonTest{
 		},
 		expectedJSON: `{"vcpus":3,"memoryBytes":4194304000,"bootloader":{"kind":"linuxBootloader","vmlinuzPath":"/vmlinuz","initrdPath":"/initrd","kernelCmdLine":"console=hvc0"},"timesync":{"vsockPort":1234}}`,
 	},
+	"TestIgnition": {
+		newVM: func(t *testing.T) *VirtualMachine {
+			vm := newLinuxVM(t)
+			ignition, err := IgnitionNew("config", "socket")
+			require.NoError(t, err)
+			vm.Ignition = ignition
+			return vm
+		},
+		expectedJSON: `{"vcpus":3,"memoryBytes":4194304000,"bootloader":{"kind":"linuxBootloader","vmlinuzPath":"/vmlinuz","initrdPath":"/initrd","kernelCmdLine":"console=hvc0"}, "ignition":{"kind":"ignition","configPath":"config","socketPath":"socket"}}`,
+	},
 	"TestVirtioRNG": {
 		newVM: func(t *testing.T) *VirtualMachine {
 			vm := newLinuxVM(t)
@@ -207,7 +217,7 @@ var jsonStabilityTests = map[string]jsonStabilityTest{
 
 			return vm
 		},
-		skipFields:   []string{"Bootloader", "Devices", "Timesync"},
+		skipFields:   []string{"Bootloader", "Devices", "Timesync", "Ignition"},
 		expectedJSON: `{"vcpus":3,"memoryBytes":3,"bootloader":{"kind":"linuxBootloader","vmlinuzPath":"/vmlinuz","kernelCmdLine":"console=hvc0","initrdPath":"/initrd"},"devices":[{"kind":"virtiorng"}],"timesync":{"vsockPort":1234}}`,
 	},
 	"RosettaShare": {