add fat32 boot partition support

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

Dockerfile

@@ -35,6 +35,7 @@ RUN apt-get update && \
         parted \
         kpartx \
         e2fsprogs \
+        dosfstools \
         mount \
         tar \
         extlinux \

builder.go

@@ -67,6 +67,7 @@ type builder struct {
 
 	splitBoot bool
 	bootSize  uint64
+	bootFS    BootFS
 
 	loDevice        string
 	bootPart        string
@@ -83,7 +84,7 @@ type builder struct {
 	cmdLineExtra string
 }
 
-func NewBuilder(ctx context.Context, workdir, imgTag, disk string, size uint64, osRelease OSRelease, format string, cmdLineExtra string, splitBoot bool, bootSize uint64, luksPassword string, bootLoader string) (Builder, error) {
+func NewBuilder(ctx context.Context, workdir, imgTag, disk string, size uint64, osRelease OSRelease, format string, cmdLineExtra string, splitBoot bool, bootFS BootFS, bootSize uint64, luksPassword string, bootLoader string) (Builder, error) {
 	if err := checkDependencies(); err != nil {
 		return nil, err
 	}
@@ -123,6 +124,19 @@ func NewBuilder(ctx context.Context, workdir, imgTag, disk string, size uint64,
 		return nil, err
 	}
 
+	if splitBoot {
+		config.Kernel = strings.TrimPrefix(config.Kernel, "/boot")
+		config.Initrd = strings.TrimPrefix(config.Initrd, "/boot")
+	}
+
+	if bootFS == "" {
+		bootFS = FSExt4
+	}
+
+	if err := bootFS.Validate(); err != nil {
+		return nil, err
+	}
+
 	blp, err := BootloaderByName(bootLoader)
 	if err != nil {
 		return nil, err
@@ -164,6 +178,7 @@ func NewBuilder(ctx context.Context, workdir, imgTag, disk string, size uint64,
 		cmdLineExtra: cmdLineExtra,
 		splitBoot:    splitBoot,
 		bootSize:     bootSize,
+		bootFS:       bootFS,
 		luksPassword: luksPassword,
 	}
 	if err := os.MkdirAll(b.mntPoint, os.ModePerm); err != nil {
@@ -303,7 +318,12 @@ func (b *builder) mountImg(ctx context.Context) error {
 	if err := os.MkdirAll(filepath.Join(b.mntPoint, "boot"), os.ModePerm); err != nil {
 		return err
 	}
-	if err := exec.Run(ctx, "mkfs.ext4", b.bootPart); err != nil {
+	if b.bootFS.IsFat() {
+		err = exec.Run(ctx, "mkfs.fat", "-F32", b.bootPart)
+	} else {
+		err = exec.Run(ctx, "mkfs.ext4", b.bootPart)
+	}
+	if err != nil {
 		return err
 	}
 	if err := exec.Run(ctx, "mount", b.bootPart, filepath.Join(b.mntPoint, "boot")); err != nil {
@@ -363,7 +383,7 @@ func (b *builder) setupRootFS(ctx context.Context) (err error) {
 				return err
 			}
 		}
-		fstab = fmt.Sprintf("UUID=%s / ext4 errors=remount-ro 0 1\nUUID=%s /boot ext4 errors=remount-ro 0 2\n", b.rootUUID, b.bootUUID)
+		fstab = fmt.Sprintf("UUID=%s / ext4 errors=remount-ro 0 1\nUUID=%s /boot %s errors=remount-ro 0 2\n", b.rootUUID, b.bootUUID, b.bootFS.linux())
 	} else {
 		b.bootUUID = b.rootUUID
 		fstab = fmt.Sprintf("UUID=%s / ext4 errors=remount-ro 0 1\n", b.bootUUID)
@@ -387,13 +407,7 @@ func (b *builder) setupRootFS(ctx context.Context) (err error) {
 	if err := os.RemoveAll(b.chPath("/.dockerenv")); err != nil {
 		return err
 	}
-	// create a symlink to /boot for non-alpine images in order to have a consistent path
+
-	// even if the image is not split
-	if _, err := os.Stat(b.chPath("/boot/boot")); os.IsNotExist(err) {
-		if err := os.Symlink(".", b.chPath("/boot/boot")); err != nil {
-			return err
-		}
-	}
 	switch b.osRelease.ID {
 	case ReleaseAlpine:
 		by, err := os.ReadFile(b.chPath("/etc/inittab"))
@@ -408,48 +422,26 @@ func (b *builder) setupRootFS(ctx context.Context) (err error) {
 			return err
 		}
 		return nil
-	case ReleaseUbuntu:
-		if b.osRelease.VersionID >= "20.04" {
-			return nil
-		}
-		fallthrough
-	case ReleaseDebian, ReleaseKali:
-		t, err := os.Readlink(b.chPath("/vmlinuz"))
-		if err != nil {
-			return err
-		}
-		if err := os.Symlink(t, b.chPath("/boot/vmlinuz")); err != nil {
-			return err
-		}
-		t, err = os.Readlink(b.chPath("/initrd.img"))
-		if err != nil {
-			return err
-		}
-		if err := os.Symlink(t, b.chPath("/boot/initrd.img")); err != nil {
-			return err
-		}
-		return nil
 	default:
 		return nil
 	}
 }
 
 func (b *builder) cmdline(_ context.Context) string {
-	if b.isLuksEnabled() {
+	if !b.isLuksEnabled() {
-		switch b.osRelease.ID {
-		case ReleaseAlpine:
-			return b.config.Cmdline(RootUUID(b.rootUUID), "root=/dev/mapper/root", "cryptdm=root", "cryptroot=UUID="+b.cryptUUID, b.cmdLineExtra)
-		case ReleaseCentOS:
-			return b.config.Cmdline(RootUUID(b.rootUUID), "rd.luks.name=UUID="+b.rootUUID+" rd.luks.uuid="+b.cryptUUID+" rd.luks.crypttab=0", b.cmdLineExtra)
-		default:
-			// for some versions of debian, the cryptopts parameter MUST contain all the following: target,source,key,opts...
-			// see https://salsa.debian.org/cryptsetup-team/cryptsetup/-/blob/debian/buster/debian/functions
-			// and https://cryptsetup-team.pages.debian.net/cryptsetup/README.initramfs.html
-			return b.config.Cmdline(nil, "root=/dev/mapper/root", "cryptopts=target=root,source=UUID="+b.cryptUUID+",key=none,luks", b.cmdLineExtra)
-		}
-	} else {
 		return b.config.Cmdline(RootUUID(b.rootUUID), b.cmdLineExtra)
 	}
+	switch b.osRelease.ID {
+	case ReleaseAlpine:
+		return b.config.Cmdline(RootUUID(b.rootUUID), "root=/dev/mapper/root", "cryptdm=root", "cryptroot=UUID="+b.cryptUUID, b.cmdLineExtra)
+	case ReleaseCentOS:
+		return b.config.Cmdline(RootUUID(b.rootUUID), "rd.luks.name=UUID="+b.rootUUID+" rd.luks.uuid="+b.cryptUUID+" rd.luks.crypttab=0", b.cmdLineExtra)
+	default:
+		// for some versions of debian, the cryptopts parameter MUST contain all the following: target,source,key,opts...
+		// see https://salsa.debian.org/cryptsetup-team/cryptsetup/-/blob/debian/buster/debian/functions
+		// and https://cryptsetup-team.pages.debian.net/cryptsetup/README.initramfs.html
+		return b.config.Cmdline(nil, "root=/dev/mapper/root", "cryptopts=target=root,source=UUID="+b.cryptUUID+",key=none,luks", b.cmdLineExtra)
+	}
 }
 
 func (b *builder) installBootloader(ctx context.Context) error {

cmd/d2vm/build.go

@@ -79,9 +79,8 @@ var (
 				}
 				return docker.RunD2VM(cmd.Context(), d2vm.Image, d2vm.Version, in, out, cmd.Name(), os.Args[2:]...)
 			}
-			if luksPassword != "" && !splitBoot {
+			if err := validateFlags(); err != nil {
-				logrus.Warnf("luks password is set: enabling split boot")
+				return err
-				splitBoot = true
 			}
 			size, err := parseSize(size)
 			if err != nil {
@@ -90,14 +89,6 @@ var (
 			if file == "" {
 				file = filepath.Join(args[0], "Dockerfile")
 			}
-			if push && tag == "" {
-				return fmt.Errorf("tag is required when pushing container disk image")
-			}
-			if _, err := os.Stat(output); err == nil || !os.IsNotExist(err) {
-				if !force {
-					return fmt.Errorf("%s already exists", output)
-				}
-			}
 			logrus.Infof("building docker image from %s", file)
 			if err := docker.Build(cmd.Context(), tag, file, args[0], buildArgs...); err != nil {
 				return err
@@ -114,6 +105,7 @@ var (
 				d2vm.WithRaw(raw),
 				d2vm.WithSplitBoot(splitBoot),
 				d2vm.WithBootSize(bootSize),
+				d2vm.WithBootFS(d2vm.BootFS(bootFS)),
 				d2vm.WithLuksPassword(luksPassword),
 				d2vm.WithKeepCache(keepCache),
 			); err != nil {

cmd/d2vm/convert.go

@@ -15,11 +15,9 @@
 package main
 
 import (
-	"fmt"
 	"os"
 	"path/filepath"
 	"runtime"
-	"strings"
 
 	"github.com/c2h5oh/datasize"
 	"github.com/sirupsen/logrus"
@@ -51,28 +49,14 @@ var (
 				}
 				return docker.RunD2VM(cmd.Context(), d2vm.Image, d2vm.Version, out, out, cmd.Name(), dargs...)
 			}
-			if luksPassword != "" && !splitBoot {
+			if err := validateFlags(); err != nil {
-				logrus.Warnf("luks password is set: enabling split boot")
+				return err
-				splitBoot = true
 			}
-			img := args[0]
-			tag := "latest"
-			if parts := strings.Split(img, ":"); len(parts) > 1 {
-				img, tag = parts[0], parts[1]
-			}
-			img = fmt.Sprintf("%s:%s", img, tag)
 			size, err := parseSize(size)
 			if err != nil {
 				return err
 			}
-			if push && tag == "" {
+			img := args[0]
-				return fmt.Errorf("tag is required when pushing container disk image")
-			}
-			if _, err := os.Stat(output); err == nil || !os.IsNotExist(err) {
-				if !force {
-					return fmt.Errorf("%s already exists", output)
-				}
-			}
 			found := false
 			if !pull {
 				imgs, err := docker.ImageList(cmd.Context(), img)
@@ -102,6 +86,7 @@ var (
 				d2vm.WithRaw(raw),
 				d2vm.WithSplitBoot(splitBoot),
 				d2vm.WithBootSize(bootSize),
+				d2vm.WithBootFS(d2vm.BootFS(bootFS)),
 				d2vm.WithLuksPassword(luksPassword),
 				d2vm.WithKeepCache(keepCache),
 			); err != nil {

cmd/d2vm/flags.go

@@ -15,8 +15,11 @@
 package main
 
 import (
+	"fmt"
+	"os"
 	"strings"
 
+	"github.com/sirupsen/logrus"
 	"github.com/spf13/pflag"
 
 	"go.linka.cloud/d2vm"
@@ -36,11 +39,35 @@ var (
 	bootloader       string
 	splitBoot        bool
 	bootSize         uint64
+	bootFS           string
 	luksPassword     string
 
 	keepCache bool
 )
 
+func validateFlags() error {
+	if luksPassword != "" && !splitBoot {
+		logrus.Warnf("luks password is set: enabling split boot")
+		splitBoot = true
+	}
+	if bootFS := d2vm.BootFS(bootFS); bootFS != "" && !bootFS.IsSupported() {
+		return fmt.Errorf("invalid boot filesystem: %s", bootFS)
+	}
+	if bootFS != "" && !splitBoot {
+		logrus.Warnf("boot filesystem is set: enabling split boot")
+		splitBoot = true
+	}
+	if push && tag == "" {
+		return fmt.Errorf("tag is required when pushing container disk image")
+	}
+	if _, err := os.Stat(output); err == nil || !os.IsNotExist(err) {
+		if !force {
+			return fmt.Errorf("%s already exists", output)
+		}
+	}
+	return nil
+}
+
 func buildFlags() *pflag.FlagSet {
 	flags := pflag.NewFlagSet("build", pflag.ExitOnError)
 	flags.StringVarP(&output, "output", "o", output, "The output image, the extension determine the image format, raw will be used if none. Supported formats: "+strings.Join(d2vm.OutputFormats(), " "))
@@ -54,6 +81,7 @@ func buildFlags() *pflag.FlagSet {
 	flags.BoolVar(&push, "push", false, "Push the container disk image to the registry")
 	flags.BoolVar(&splitBoot, "split-boot", false, "Split the boot partition from the root partition")
 	flags.Uint64Var(&bootSize, "boot-size", 100, "Size of the boot partition in MB")
+	flags.StringVar(&bootFS, "boot-fs", "", "Filesystem to use for the boot partition, ext4 or fat32")
 	flags.StringVar(&bootloader, "bootloader", "syslinux", "Bootloader to use: syslinux, grub")
 	flags.StringVar(&luksPassword, "luks-password", "", "Password to use for the LUKS encrypted root partition. If not set, the root partition will not be encrypted")
 	flags.BoolVar(&keepCache, "keep-cache", false, "Keep the images after the build")

config.go

@@ -25,8 +25,8 @@ var (
 		Initrd: "/boot/initrd.img",
 	}
 	configDebian = Config{
-		Kernel: "/vmlinuz",
+		Kernel: "/boot/vmlinuz",
-		Initrd: "/initrd.img",
+		Initrd: "/boot/initrd.img",
 	}
 	configAlpine = Config{
 		Kernel: "/boot/vmlinuz-virt",

convert.go

@@ -88,7 +88,7 @@ func Convert(ctx context.Context, img string, opts ...ConvertOption) error {
 	if format == "" {
 		format = "raw"
 	}
-	b, err := NewBuilder(ctx, tmpPath, imgUUID, "", o.size, r, format, o.cmdLineExtra, o.splitBoot, o.bootSize, o.luksPassword, o.bootLoader)
+	b, err := NewBuilder(ctx, tmpPath, imgUUID, "", o.size, r, format, o.cmdLineExtra, o.splitBoot, o.bootFS, o.bootSize, o.luksPassword, o.bootLoader)
 	if err != nil {
 		return err
 	}

convert_options.go

@@ -27,6 +27,7 @@ type convertOptions struct {
 
 	splitBoot bool
 	bootSize  uint64
+	bootFS    BootFS
 
 	luksPassword string
 
@@ -87,6 +88,12 @@ func WithBootSize(bootSize uint64) ConvertOption {
 	}
 }
 
+func WithBootFS(bootFS BootFS) ConvertOption {
+	return func(o *convertOptions) {
+		o.bootFS = bootFS
+	}
+}
+
 func WithLuksPassword(password string) ConvertOption {
 	return func(o *convertOptions) {
 		o.luksPassword = password

fs.go

@@ -0,0 +1,58 @@
+// Copyright 2023 Linka Cloud  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.
+
+package d2vm
+
+import (
+	"fmt"
+)
+
+type BootFS string
+
+const (
+	FSExt4  BootFS = "ext4"
+	FSFat32 BootFS = "fat32"
+)
+
+func (f BootFS) String() string {
+	return string(f)
+}
+
+func (f BootFS) IsExt() bool {
+	return f == FSExt4
+}
+
+func (f BootFS) IsFat() bool {
+	return f == FSFat32
+}
+
+func (f BootFS) IsSupported() bool {
+	return f.IsExt() || f.IsFat()
+}
+
+func (f BootFS) Validate() error {
+	if !f.IsSupported() {
+		fmt.Errorf("invalid boot filesystem: %s valid filesystems are: fat32, ext4", f)
+	}
+	return nil
+}
+
+func (f BootFS) linux() string {
+	switch f {
+	case FSFat32:
+		return "vfat"
+	default:
+		return "ext4"
+	}
+}

templates/alpine.Dockerfile

@@ -14,7 +14,8 @@ RUN apk update --no-cache && \
 {{- else }}
       busybox-initscripts \
 {{- end }}
-      openrc
+      openrc && \
+      find /boot -type l -exec rm {} \;
 
 RUN for s in bootmisc hostname hwclock modules networking swap sysctl urandom syslog; do rc-update add $s boot; done
 RUN for s in devfs dmesg hwdrivers mdev; do rc-update add $s sysinit; done

templates/centos.Dockerfile

@@ -18,10 +18,13 @@ RUN yum install -y \
     sudo && \
     systemctl enable NetworkManager && \
     systemctl unmask systemd-remount-fs.service && \
-    systemctl unmask getty.target && \
+    systemctl unmask getty.target
-    cd /boot && \
+
-    ln -s $(find . -name 'vmlinuz-*') vmlinuz && \
+{{- if not .Grub }}
-    ln -s $(find . -name 'initramfs-*.img') initrd.img
+RUN cd /boot && \
+        mv $(find . -name 'vmlinuz-*') /boot/vmlinuz && \
+        mv $(find . -name 'initramfs-*.img') /boot/initrd.img
+{{- end }}
 
 {{ if .Luks }}
 RUN yum install -y cryptsetup && \

templates/debian.Dockerfile

@@ -12,7 +12,13 @@ RUN echo "deb http://archive.debian.org/debian stretch main" > /etc/apt/sources.
 
 RUN apt-get -y update && \
     DEBIAN_FRONTEND=noninteractive apt-get -y install --no-install-recommends \
-      linux-image-amd64
+      linux-image-amd64 && \
+      find /boot -type l -exec rm {} \;
+
+{{- if not .Grub }}
+RUN mv $(find /boot -name 'vmlinuz-*') /boot/vmlinuz && \
+      mv $(find /boot -name 'initrd.img-*') /boot/initrd.img
+{{- end }}
 
 RUN DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
       systemd-sysv \

templates/ubuntu.Dockerfile

@@ -14,7 +14,13 @@ RUN apt-get update -y && \
   dbus \
   isc-dhcp-client \
   iproute2 \
-  iputils-ping
+  iputils-ping && \
+  find /boot -type l -exec rm {} \;
+
+{{- if not .Grub }}
+RUN mv $(find /boot -name 'vmlinuz-*') /boot/vmlinuz && \
+      mv $(find /boot -name 'initrd.img-*') /boot/initrd.img
+{{- end }}
 
 RUN systemctl preset-all