feat: add --hostname flag to customize the vm hostname

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

README.md

@@ -171,6 +171,7 @@ Flags:
       --bootloader string          Bootloader to use: syslinux, grub, grub-bios, grub-efi, defaults to syslinux on amd64 and grub-efi on arm64
       --force                      Override output qcow2 image
   -h, --help                       help for convert
+      --hostname string            Hostname to set in the generated image (default "localhost")
       --keep-cache                 Keep the images after the build
       --luks-password string       Password to use for the LUKS encrypted root partition. If not set, the root partition will not be encrypted
       --network-manager string     Network manager to use for the image: none, netplan, ifupdown
@@ -331,6 +332,7 @@ Flags:
   -f, --file string                Name of the Dockerfile
       --force                      Override output qcow2 image
   -h, --help                       help for build
+      --hostname string            Hostname to set in the generated image (default "localhost")
       --keep-cache                 Keep the images after the build
       --luks-password string       Password to use for the LUKS encrypted root partition. If not set, the root partition will not be encrypted
       --network-manager string     Network manager to use for the image: none, netplan, ifupdown

builder.go

@@ -83,9 +83,11 @@ type builder struct {
 
 	cmdLineExtra string
 	arch         string
+
+	hostname string
 }
 
-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, platform 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, platform, hostname string) (Builder, error) {
 	var arch string
 	switch platform {
 	case "linux/amd64":
@@ -179,6 +181,9 @@ func NewBuilder(ctx context.Context, workdir, imgTag, disk string, size uint64,
 	// 	logrus.Warnf("%s is smaller than rootfs size, using %s", datasize.ByteSize(size), s)
 	// 	size = int64(s)
 	// }
+	if hostname == "" {
+		hostname = "localhost"
+	}
 	b := &builder{
 		osRelease:    osRelease,
 		config:       config,
@@ -195,6 +200,7 @@ func NewBuilder(ctx context.Context, workdir, imgTag, disk string, size uint64,
 		bootFS:       bootFS,
 		luksPassword: luksPassword,
 		arch:         arch,
+		hostname:     hostname,
 	}
 	if err := b.checkDependencies(); err != nil {
 		return nil, err
@@ -412,7 +418,7 @@ func (b *builder) setupRootFS(ctx context.Context) (err error) {
 	if err := b.chWriteFileIfNotExist("/etc/resolv.conf", "nameserver 8.8.8.8", 0644); err != nil {
 		return err
 	}
-	if err := b.chWriteFileIfNotExist("/etc/hostname", "localhost", perm); err != nil {
+	if err := b.chWriteFile("/etc/hostname", b.hostname+"\n", perm); err != nil {
 		return err
 	}
 	if err := b.chWriteFileIfNotExist("/etc/hosts", hosts, perm); err != nil {

cmd/d2vm/build.go

@@ -110,6 +110,7 @@ var (
 				d2vm.WithKeepCache(keepCache),
 				d2vm.WithPlatform(platform),
 				d2vm.WithPull(false),
+				d2vm.WithHostname(hostname),
 			); err != nil {
 				return err
 			}

cmd/d2vm/convert.go

@@ -91,6 +91,7 @@ var (
 				d2vm.WithKeepCache(keepCache),
 				d2vm.WithPlatform(platform),
 				d2vm.WithPull(pull),
+				d2vm.WithHostname(hostname),
 			); err != nil {
 				return err
 			}

cmd/d2vm/flags.go

@@ -44,6 +44,8 @@ var (
 
 	keepCache bool
 	platform  string
+
+	hostname string
 )
 
 func validateFlags() error {
@@ -116,5 +118,6 @@ func buildFlags() *pflag.FlagSet {
 	flags.BoolVar(&keepCache, "keep-cache", false, "Keep the images after the build")
 	flags.StringVar(&platform, "platform", d2vm.Arch, "Platform to use for the container disk image, linux/arm64 and linux/arm64 are supported")
 	flags.BoolVar(&pull, "pull", false, "Always pull docker image")
+	flags.StringVar(&hostname, "hostname", "localhost", "Hostname to set in the generated image")
 	return flags
 }

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.bootFS, o.bootSize, o.luksPassword, o.bootLoader, o.platform)
+	b, err := NewBuilder(ctx, tmpPath, imgUUID, "", o.size, r, format, o.cmdLineExtra, o.splitBoot, o.bootFS, o.bootSize, o.luksPassword, o.bootLoader, o.platform, o.hostname)
 	if err != nil {
 		return err
 	}

convert_options.go

@@ -34,6 +34,8 @@ type convertOptions struct {
 	keepCache bool
 	platform  string
 	pull      bool
+
+	hostname string
 }
 
 func (o *convertOptions) hasGrubBIOS() bool {
@@ -127,3 +129,9 @@ func WithPull(b bool) ConvertOption {
 		o.pull = b
 	}
 }
+
+func WithHostname(hostname string) ConvertOption {
+	return func(o *convertOptions) {
+		o.hostname = hostname
+	}
+}

docs/content/reference/d2vm_build.md

@@ -17,6 +17,7 @@ d2vm build [context directory] [flags]
   -f, --file string                Name of the Dockerfile
       --force                      Override output qcow2 image
   -h, --help                       help for build
+      --hostname string            Hostname to set in the generated image (default "localhost")
       --keep-cache                 Keep the images after the build
       --luks-password string       Password to use for the LUKS encrypted root partition. If not set, the root partition will not be encrypted
       --network-manager string     Network manager to use for the image: none, netplan, ifupdown

docs/content/reference/d2vm_convert.md

@@ -15,6 +15,7 @@ d2vm convert [docker image] [flags]
       --bootloader string          Bootloader to use: syslinux, grub, grub-bios, grub-efi, defaults to syslinux on amd64 and grub-efi on arm64
       --force                      Override output qcow2 image
   -h, --help                       help for convert
+      --hostname string            Hostname to set in the generated image (default "localhost")
       --keep-cache                 Keep the images after the build
       --luks-password string       Password to use for the LUKS encrypted root partition. If not set, the root partition will not be encrypted
       --network-manager string     Network manager to use for the image: none, netplan, ifupdown