refactor: improve metal platform

This brings in a few minor improvements to the metal platform. The first
is to use talos.config=metal-iso to indicate that the machine's config
can be found in an ISO image. The second is a fix to ensure that /mnt
exists.

This adds support for creating more than one node using the qemu-boot.sh
script.

Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>

Dockerfile

@@ -220,7 +220,7 @@ COPY hack/containerd.toml /etc/containerd-system.toml
 RUN touch /rootfs/etc/resolv.conf
 RUN touch /rootfs/etc/hosts
 RUN touch /rootfs/etc/os-release
-RUN mkdir -pv /rootfs/{boot,usr/local/share}
+RUN mkdir -pv /rootfs/{boot,usr/local/share,mnt}
 RUN mkdir -pv /rootfs/{etc/kubernetes/manifests,etc/cni,usr/libexec/kubernetes}
 RUN ln -s /etc/ssl /rootfs/etc/pki
 RUN ln -s /etc/ssl /rootfs/usr/share/ca-certificates

internal/pkg/platform/metal/metal.go

@@ -7,8 +7,7 @@ package metal
 import (
 	"io/ioutil"
 	"net"
-	"os"
-	"path"
+	"path/filepath"
 
 	"github.com/pkg/errors"
 	"golang.org/x/sys/unix"
@@ -39,37 +38,12 @@ func (b *Metal) Configuration() ([]byte, error) {
 		return nil, errors.Errorf("no config option was found")
 	}
 
-	if *option == constants.UserDataCIData {
-		var dev *probe.ProbedBlockDevice
-
-		dev, err := probe.GetDevWithFileSystemLabel(constants.UserDataCIData)
-		if err != nil {
-			return nil, errors.Errorf("failed to find %s iso: %v", constants.UserDataCIData, err)
-		}
-
-		if err = os.Mkdir(mnt, 0700); err != nil {
-			return nil, errors.Errorf("failed to mkdir: %v", err)
-		}
-
-		if err = unix.Mount(dev.Path, mnt, dev.SuperBlock.Type(), unix.MS_RDONLY, ""); err != nil {
-			return nil, errors.Errorf("failed to mount iso: %v", err)
-		}
-
-		var b []byte
-
-		b, err = ioutil.ReadFile(path.Join(mnt, "user-data"))
-		if err != nil {
-			return nil, errors.Errorf("read config: %s", err.Error())
-		}
-
-		if err = unix.Unmount(mnt, 0); err != nil {
-			return nil, errors.Errorf("failed to unmount: %v", err)
-		}
-
-		return b, nil
+	switch *option {
+	case constants.MetalConfigISOLabel:
+		return readConfigFromISO()
+	default:
+		return config.Download(*option)
 	}
-
-	return config.Download(*option)
 }
 
 // Mode implements the platform.Platform interface.
@@ -86,3 +60,27 @@ func (b *Metal) Hostname() (hostname []byte, err error) {
 func (b *Metal) ExternalIPs() (addrs []net.IP, err error) {
 	return addrs, err
 }
+
+func readConfigFromISO() (b []byte, err error) {
+	var dev *probe.ProbedBlockDevice
+
+	dev, err = probe.GetDevWithFileSystemLabel(constants.MetalConfigISOLabel)
+	if err != nil {
+		return nil, errors.Errorf("failed to find %s iso: %v", constants.MetalConfigISOLabel, err)
+	}
+
+	if err = unix.Mount(dev.Path, mnt, dev.SuperBlock.Type(), unix.MS_RDONLY, ""); err != nil {
+		return nil, errors.Errorf("failed to mount iso: %v", err)
+	}
+
+	b, err = ioutil.ReadFile(filepath.Join(mnt, filepath.Base(constants.ConfigPath)))
+	if err != nil {
+		return nil, errors.Errorf("read config: %s", err.Error())
+	}
+
+	if err = unix.Unmount(mnt, 0); err != nil {
+		return nil, errors.Errorf("failed to unmount: %v", err)
+	}
+
+	return b, nil
+}

internal/pkg/runtime/initializer/metal/metal.go

@@ -5,6 +5,7 @@
 package metal
 
 import (
+	"errors"
 	"strings"
 
 	"github.com/talos-systems/talos/internal/pkg/event"
@@ -29,14 +30,16 @@ func (b *Metal) Initialize(platform platform.Platform, install machine.Install)
 
 	mountpoints, err = owned.MountPointsFromLabels()
 	if err != nil {
-		// if install.Image() == "" {
-		// 	install.Image() = fmt.Sprintf("%s:%s", constants.DefaultInstallerImageRepository, version.Tag)
-		// }
+		if install.Image() == "" {
+			return errors.New("an install image is required")
+		}
+
 		if err = installer.Install(install.Image(), install.Disk(), strings.ToLower(platform.Name())); err != nil {
 			return err
 		}
 
 		event.Bus().Notify(event.Event{Type: event.Reboot})
+
 		// Prevent the task from returning to prevent the next phase from
 		// running.
 		select {}

pkg/constants/constants.go

@@ -158,9 +158,8 @@ const (
 	// ConfigPath is the path to the downloaded config.
 	ConfigPath = "/run/config.yaml"
 
-	// UserDataCIData is the volume label for NoCloud cloud-init.
-	// See https://cloudinit.readthedocs.io/en/latest/topics/datasources/nocloud.html#datasource-nocloud.
-	UserDataCIData = "cidata"
+	// MetalConfigISOLabel is the volume label for ISO based configuration.
+	MetalConfigISOLabel = "metal-iso"
 
 	// ConfigGuestInfo is the name of the VMware guestinfo config strategy.
 	ConfigGuestInfo = "guestinfo"