[mic][iso] Added the ability to customize an existing mic-generated iso.

toolkit/tools/imagecustomizer/docs/iso.md

@@ -2,26 +2,29 @@
 
 ## Overview
 
-Given a full disk image generated by the Azure Linux toolkit, the Azure Linux
-Image Customizer can generate a LiveOS ISO image when the
-`--output-image-format` is set to `iso`.
-
-The LiveOS ISO image is a bootable image that boots into the rootfs of the
-input full disk image. This eliminates the requirement to install that image
-to persistent storage before booting it.
-
-All customizations can still be made to the input full disk image rootfs as
-usual using MIC, and will naturally carry over into the LiveOS ISO. This
-includes customizations for kernel modules, dracut, and other early boot-time
-actions.
-
-While converting the input full disk image into a LiveOS ISO involves copying
+The Azure Linux Image Customizer can customize an input image and package the
+output as a LiveOS iso image. The input image can be a full disk image
+(vhd/vhdx/qcow2/raw) or another LiveOS iso image. The LiveOS iso output format
+is specified by setting the `--output-image-format` command line parameter to
+`iso`.
+
+The LiveOS iso image is a bootable image that boots into a rootfs image
+included on the iso media without the need to have anything pre-installed
+on the target machine. The rootfs is kept read-only and an overlay in memory
+is created so that processes can successfully write state.
+
+Customizations are made to the input rootfs as usual using the Azure Linux
+Image Customizer, and will naturally carry over into the LiveOS iso image.
+This includes customizations for kernel modules, dracut, and other early
+boot-time actions.
+
+While converting the input full disk image into a LiveOS iso involves copying
 almost all the artifacts unchanged - some artifacts are changed as follows:
 - `grub.cfg` is modified by updating the kernel command-line arguments as
   follows:
   - the root is updated to the LiveOS root file system image.
   - the LiveOS dracut parameters are appended.
-  - the MIC user-specified new parameters are appended.
+  - the user-specified new parameters are appended.
   - SELinux is disabled.
 - `/etc/fstab` is dropped from the rootfs as it typically conflicts with the
   overlay setup required by the LiveOS.
@@ -31,16 +34,16 @@ almost all the artifacts unchanged - some artifacts are changed as follows:
   dracut configuration that got used before will be re-used again when we are
   re-generating the `initrd.img` and hence the original behavior is retained.
 
-The current implementation for the LiveOS ISO does not support the following:
+The current implementation for the LiveOS iso does not support the following:
 - persistent storage.
   - The machine loses all its state on reboot or shutdown.
 - dm-verity.
-  - The ISO image cannot run dm-verity for the LiveOS partitions.
+  - The iso image cannot run dm-verity for the LiveOS partitions.
 - disk layout.
   - There is always one disk generated when an `iso` output format is
     specified.
 - SELinux
-  - No SELinux configuration is supported for the generated ISO image.
+  - No SELinux configuration is supported for the generated iso image.
 - non-"Azure Linux toolkit" images
   - images generated by tools other than the Azure Linux toolkit may fail to be
     converted to a LiveOS iso. This is due to certain assumptions on the input
@@ -80,11 +83,6 @@ iso:
     cloud-init-data/meta-data: /cloud-init-data/meta-data
   kernelCommandLine:
     ExtraCommandLine: "'ds=nocloud;s=file://run/initramfs/live/cloud-init-data'"
-os:
-  users:
-  - name: test
-    password: testpassword
-    primaryGroup: sudo
 ```
 
 #### Example 2
@@ -96,10 +94,6 @@ iso:
   kernelCommandLine:
     extraCommandLine: "'ds=nocloud;s=file://cloud-init-data'"
 os:
-  users:
-  - name: test
-    password: testpassword
-    primaryGroup: sudo
   additionalFiles:
     cloud-init-data/user-data: /cloud-init-data/user-data
     cloud-init-data/network-config: /cloud-init-data/network-config
@@ -111,15 +105,20 @@ os:
 ### Full Disk Image
 
 The input full disk image must satisfy the following requirements in order for
-MIC to be able to generate an iso image out of it:
+the Azure Linux Image Cuztomizer to be able to generate an iso image out of it:
 - File layout (after all partitions have been mounted):
   - `/boot/grub2/grub.cfg` must exist and is the 'main' grub configuration (not
     a redirection grub configuration file for example).
   - The bootloader and the shim must exist under the `/boot` folder or any of
     its subdirectories.
     - For x64, `bootx64.efi` and `grubx64.efi` (or `grubx64-noprefix.efi`).
-    - For ARM64, `bootaa64.efi` and `grubaa64.efi` (or `grubx64-noprefix.efi`).
+    - For ARM64, `bootaa64.efi` and `grubaa64.efi` (or `grubaa64-noprefix.efi`).
   - All grub configurations and related files must be stored under the `/boot`
     folder. For example, grub.cfg cannot reference files outside that folder.
     If it does, those referenced files will not be copied to the iso and may
     cause grub to fail booting the desired operating system.
+
+### LiveOS ISO Image
+
+The input LiveOS iso image must be previously generated by the Azure Linux Image
+Customizer.

toolkit/tools/imagecustomizerapi/config.go

@@ -8,16 +8,19 @@ import "fmt"
 type Config struct {
 	Storage *Storage `yaml:"storage"`
 	Iso     *Iso     `yaml:"iso"`
-	OS      OS       `yaml:"os"`
-	Scripts Scripts  `yaml:"scripts"`
+	OS      *OS      `yaml:"os"`
+	Scripts *Scripts `yaml:"scripts"`
 }
 
 func (c *Config) IsValid() (err error) {
+
+	hasStorage := false
 	if c.Storage != nil {
 		err = c.Storage.IsValid()
 		if err != nil {
 			return err
 		}
+		hasStorage = true
 	}
 
 	if c.Iso != nil {
@@ -27,19 +30,22 @@ func (c *Config) IsValid() (err error) {
 		}
 	}
 
-	err = c.OS.IsValid()
-	if err != nil {
-		return err
+	hasResetBootLoader := false
+	if c.OS != nil {
+		err = c.OS.IsValid()
+		if err != nil {
+			return err
+		}
+		hasResetBootLoader = c.OS.ResetBootLoaderType != ResetBootLoaderTypeDefault
 	}
 
-	err = c.Scripts.IsValid()
-	if err != nil {
-		return err
+	if c.Scripts != nil {
+		err = c.Scripts.IsValid()
+		if err != nil {
+			return err
+		}
 	}
 
-	hasStorage := c.Storage != nil
-	hasResetBootLoader := c.OS.ResetBootLoaderType != ResetBootLoaderTypeDefault
-
 	if hasStorage != hasResetBootLoader {
 		return fmt.Errorf("os.resetBootLoaderType and storage must be specified together")
 	}

toolkit/tools/imagecustomizerapi/config_test.go

@@ -35,7 +35,7 @@ func TestConfigIsValid(t *testing.T) {
 				},
 			},
 		},
-		OS: OS{
+		OS: &OS{
 			ResetBootLoaderType: "hard-reset",
 			Hostname:            "test",
 		},
@@ -67,7 +67,7 @@ func TestConfigIsValidLegacy(t *testing.T) {
 				},
 			},
 		},
-		OS: OS{
+		OS: &OS{
 			ResetBootLoaderType: "hard-reset",
 			Hostname:            "test",
 		},
@@ -91,7 +91,7 @@ func TestConfigIsValidNoBootType(t *testing.T) {
 				},
 			}},
 		},
-		OS: OS{
+		OS: &OS{
 			Hostname:            "test",
 			ResetBootLoaderType: "hard-reset",
 		},
@@ -127,7 +127,7 @@ func TestConfigIsValidMissingBootLoaderReset(t *testing.T) {
 				},
 			},
 		},
-		OS: OS{
+		OS: &OS{
 			Hostname: "test",
 		},
 	}
@@ -152,7 +152,7 @@ func TestConfigIsValidMultipleDisks(t *testing.T) {
 			},
 			BootType: "legacy",
 		},
-		OS: OS{
+		OS: &OS{
 			ResetBootLoaderType: "hard-reset",
 			Hostname:            "test",
 		},
@@ -169,7 +169,7 @@ func TestConfigIsValidZeroDisks(t *testing.T) {
 			BootType: BootTypeEfi,
 			Disks:    []Disk{},
 		},
-		OS: OS{
+		OS: &OS{
 			Hostname: "test",
 		},
 	}
@@ -181,7 +181,7 @@ func TestConfigIsValidZeroDisks(t *testing.T) {
 
 func TestConfigIsValidBadHostname(t *testing.T) {
 	config := &Config{
-		OS: OS{
+		OS: &OS{
 			Hostname: "test_",
 		},
 	}
@@ -200,7 +200,7 @@ func TestConfigIsValidBadDisk(t *testing.T) {
 				MaxSize:            0,
 			}},
 		},
-		OS: OS{
+		OS: &OS{
 			Hostname: "test",
 		},
 	}
@@ -220,7 +220,7 @@ func TestConfigIsValidMissingEsp(t *testing.T) {
 			}},
 			BootType: "efi",
 		},
-		OS: OS{
+		OS: &OS{
 			ResetBootLoaderType: "hard-reset",
 			Hostname:            "test",
 		},
@@ -242,7 +242,7 @@ func TestConfigIsValidMissingBiosBoot(t *testing.T) {
 			}},
 			BootType: "legacy",
 		},
-		OS: OS{
+		OS: &OS{
 			ResetBootLoaderType: "hard-reset",
 			Hostname:            "test",
 		},
@@ -279,7 +279,7 @@ func TestConfigIsValidInvalidMountPoint(t *testing.T) {
 				},
 			},
 		},
-		OS: OS{
+		OS: &OS{
 			ResetBootLoaderType: "hard-reset",
 			Hostname:            "test",
 		},
@@ -316,7 +316,7 @@ func TestConfigIsValidKernelCLI(t *testing.T) {
 				},
 			},
 		},
-		OS: OS{
+		OS: &OS{
 			ResetBootLoaderType: "hard-reset",
 			Hostname:            "test",
 			KernelCommandLine: KernelCommandLine{

toolkit/tools/pkg/imagecustomizerlib/customizeutils.go

@@ -43,7 +43,7 @@ func doCustomizations(buildDir string, baseConfigPath string, config *imagecusto
 		return err
 	}
 
-	err = addRemoveAndUpdatePackages(buildDir, baseConfigPath, &config.OS, imageChroot, rpmsSources,
+	err = addRemoveAndUpdatePackages(buildDir, baseConfigPath, config.OS, imageChroot, rpmsSources,
 		useBaseImageRpmRepos)
 	if err != nil {
 		return err
@@ -112,9 +112,11 @@ func doCustomizations(buildDir string, baseConfigPath string, config *imagecusto
 		}
 	}
 
-	err = runScripts(baseConfigPath, config.Scripts.PostCustomization, imageChroot)
-	if err != nil {
-		return err
+	if config.Scripts != nil {
+		err = runScripts(baseConfigPath, config.Scripts.PostCustomization, imageChroot)
+		if err != nil {
+			return err
+		}
 	}
 
 	err = selinuxSetFiles(selinuxMode, imageChroot)
@@ -127,9 +129,11 @@ func doCustomizations(buildDir string, baseConfigPath string, config *imagecusto
 		return err
 	}
 
-	err = runScripts(baseConfigPath, config.Scripts.FinalizeCustomization, imageChroot)
-	if err != nil {
-		return err
+	if config.Scripts != nil {
+		err = runScripts(baseConfigPath, config.Scripts.FinalizeCustomization, imageChroot)
+		if err != nil {
+			return err
+		}
 	}
 
 	return nil
@@ -440,6 +444,9 @@ func handleBootLoader(baseConfigPath string, config *imagecustomizerapi.Config,
 	case imagecustomizerapi.ResetBootLoaderTypeHard:
 		logger.Log.Infof("Resetting bootloader config")
 
+		if config.Storage == nil {
+			return fmt.Errorf("failed to configure bootloader. Missing 'storage' configuration.")
+		}
 		// Hard-reset the grub config.
 		err := configureDiskBootLoader(imageConnection, config.Storage.FileSystems,
 			config.Storage.BootType, config.OS.SELinux, config.OS.KernelCommandLine, currentSelinuxMode)