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Merged
merged 1 commit into from
Jun 26, 2025
Merged

Image Customizer: Add multi-kernel support for ISO/PXE flows #272

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4 changes: 2 additions & 2 deletions test/vmtests/vmtests/test_min_change.py
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Original file line number Diff line number Diff line change
Expand Up @@ -283,7 +283,7 @@ def test_min_change_efi_azl2_iso_output(
close_list: List[Closeable],
) -> None:
azl_release = 2
config_path = TEST_CONFIGS_DIR.joinpath("iso-bootstrap-vm.yaml")
config_path = TEST_CONFIGS_DIR.joinpath("iso-bootstrap-vm-azl2.yaml")
output_format = "iso"

run_min_change_test(
Expand Down Expand Up @@ -377,7 +377,7 @@ def test_min_change_legacy_azl2_iso_output(
close_list: List[Closeable],
) -> None:
azl_release = 2
config_path = TEST_CONFIGS_DIR.joinpath("iso-bootstrap-vm.yaml")
config_path = TEST_CONFIGS_DIR.joinpath("iso-bootstrap-vm-azl2.yaml")
output_format = "iso"

run_min_change_test(
Expand Down
31 changes: 30 additions & 1 deletion toolkit/tools/pkg/imagecustomizerlib/grubcfgutils.go
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Original file line number Diff line number Diff line change
Expand Up @@ -192,7 +192,8 @@ func FindNonRecoveryLinuxLine(inputGrubCfgContent string) ([]grub.Line, error) {
return linuxLines, nil
}

// Overrides the path of the kernel binary of all the linux commands within a grub config file.
// Overrides the path of the kernel binary/initrd image in all the linux
// commands within a grub config file.
func setLinuxOrInitrdPathAll(inputGrubCfgContent string, commandName string, filePath string, allowMultiple bool) (outputGrubCfgContent string, oldFilePaths []string, err error) {
quotedFilePath := grub.QuoteString(filePath)

Expand All @@ -218,6 +219,34 @@ func setLinuxOrInitrdPathAll(inputGrubCfgContent string, commandName string, fil
return outputGrubCfgContent, oldFilePaths, nil
}

// Prefixes the path of the kernel binary/initrd image in all the linux
// commands within a grub config file.
func prependLinuxOrInitrdPathAll(inputGrubCfgContent string, commandName string, prefix string, allowMultiple bool) (outputGrubCfgContent string, oldFilePaths []string, err error) {
lines, err := findLinuxOrInitrdLineAll(inputGrubCfgContent, commandName, allowMultiple)
if err != nil {
return "", nil, err
}

outputGrubCfgContent = inputGrubCfgContent
// loop from last to first so that the captured locations from
// findGrubCommandAll are not invalidated as reconstructing
// outputGrubCfgContent.
for i := len(lines) - 1; i >= 0; i-- {
line := lines[i]
linuxFilePathToken := line.Tokens[1]
start := linuxFilePathToken.Loc.Start.Index
end := linuxFilePathToken.Loc.End.Index

oldFilePath := inputGrubCfgContent[start:end]
oldFilePaths = append(oldFilePaths, oldFilePath)
if !strings.HasPrefix(oldFilePath, prefix) {
outputGrubCfgContent = outputGrubCfgContent[:start] + prefix + outputGrubCfgContent[start:]
}
}

return outputGrubCfgContent, oldFilePaths, nil
}

// Overrides the path of the kernel binary of the linux command within a grub config file.
func setLinuxPath(inputGrubCfgContent string, linuxPath string) (outputGrubCfgContent string, oldKernelPath string, err error) {
outputGrubCfgContent, oldKernelPaths, err := setLinuxOrInitrdPathAll(inputGrubCfgContent, linuxCommand, linuxPath, false /*allowMultiple*/)
Expand Down
152 changes: 89 additions & 63 deletions toolkit/tools/pkg/imagecustomizerlib/liveosisoartifactstore.go
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@ package imagecustomizerlib

import (
"fmt"
"io/fs"
"os"
"path/filepath"
"regexp"
Expand All @@ -29,13 +28,22 @@ const (
savedConfigsFileNamePath = "/" + savedConfigsDir + "/" + savedConfigsFileName
)

var (
kernelVersionRegEx = regexp.MustCompile(`\b(\d+\.\d+\.\d+\.\d+-\d+\.(azl|cm)\d)\b`)
)

type IsoInfoStore struct {
kernelVersion string
seLinuxMode imagecustomizerapi.SELinuxMode
dracutPackageInfo *PackageVersionInformation
selinuxPolicyPackageInfo *PackageVersionInformation
}

type KernelBootFiles struct {
vmlinuzPath string
initrdImagePath string
otherFiles []string
}

type IsoFilesStore struct {
artifactsDir string
bootEfiPath string
Expand All @@ -44,8 +52,8 @@ type IsoFilesStore struct {
isoGrubCfgPath string
pxeGrubCfgPath string
savedConfigsFilePath string
vmlinuzPath string
initrdImagePath string
kernelBootFiles map[string]*KernelBootFiles // kernel-version -> KernelBootFiles
initrdImagePath string // non-kernel specific
squashfsImagePath string
additionalFiles map[string]string // local-build-path -> iso-media-path
}
Expand Down Expand Up @@ -82,53 +90,60 @@ func containsGrubNoPrefix(filePaths []string) (bool, error) {
return false, nil
}

func findKernelVersion(imageRootDir string) (kernelVersion string, err error) {
const kernelModulesDir = "/usr/lib/modules"
func getSELinuxMode(imageChroot *safechroot.Chroot) (imagecustomizerapi.SELinuxMode, error) {
bootCustomizer, err := NewBootCustomizer(imageChroot)
if err != nil {
return imagecustomizerapi.SELinuxModeDefault, err
}

kernelParentPath := filepath.Join(imageRootDir, kernelModulesDir)
kernelDirs, err := os.ReadDir(kernelParentPath)
imageSELinuxMode, err := bootCustomizer.GetSELinuxMode(imageChroot)
if err != nil {
return "", fmt.Errorf("failed to enumerate kernels under (%s):\n%w", kernelParentPath, err)
return imagecustomizerapi.SELinuxModeDefault, fmt.Errorf("failed to get current SELinux mode:\n%w", err)
}

// Filter out directories that are empty.
// Some versions of Azure Linux 2.0 don't cleanup properly when the kernel package is uninstalled.
filteredKernelDirs := []fs.DirEntry(nil)
for _, kernelDir := range kernelDirs {
kernelPath := filepath.Join(kernelParentPath, kernelDir.Name())
empty, err := file.IsDirEmpty(kernelPath)
if err != nil {
return "", err
}
return imageSELinuxMode, nil
}

if !empty {
filteredKernelDirs = append(filteredKernelDirs, kernelDir)
}
func getKernelVersions(filesStore *IsoFilesStore) []string {
var kernelVersions []string
for k := range filesStore.kernelBootFiles {
kernelVersions = append(kernelVersions, k)
}

if len(filteredKernelDirs) == 0 {
return "", fmt.Errorf("did not find any kernels installed under (%s)", kernelModulesDir)
}
if len(filteredKernelDirs) > 1 {
return "", fmt.Errorf("unsupported scenario: found more than one kernel under (%s)", kernelModulesDir)
}
kernelVersion = filteredKernelDirs[0].Name()
logger.Log.Debugf("Found installed kernel version (%s)", kernelVersion)
return kernelVersion, nil
return kernelVersions
}

func getSELinuxMode(imageChroot *safechroot.Chroot) (imagecustomizerapi.SELinuxMode, error) {
bootCustomizer, err := NewBootCustomizer(imageChroot)
if err != nil {
return imagecustomizerapi.SELinuxModeDefault, err
func storeIfKernelSpecificFile(filesStore *IsoFilesStore, targetPath string) bool {
scheduleAdditionalFile := true

baseFileName := filepath.Base(targetPath)

matches := kernelVersionRegEx.FindStringSubmatch(baseFileName)
if len(matches) <= 1 {
return scheduleAdditionalFile
}

imageSELinuxMode, err := bootCustomizer.GetSELinuxMode(imageChroot)
if err != nil {
return imagecustomizerapi.SELinuxModeDefault, fmt.Errorf("failed to get current SELinux mode:\n%w", err)
kernelVersion := matches[1]

// Ensure we have an entry in the map for it
kernelBootFiles, exists := filesStore.kernelBootFiles[kernelVersion]
if !exists {
kernelBootFiles = &KernelBootFiles{}
filesStore.kernelBootFiles[kernelVersion] = kernelBootFiles
}

return imageSELinuxMode, nil
if strings.HasPrefix(baseFileName, vmLinuzPrefix) {
kernelBootFiles.vmlinuzPath = targetPath
scheduleAdditionalFile = false
} else if strings.HasPrefix(baseFileName, initramfsPrefix) || strings.HasPrefix(baseFileName, initrdPrefix) {
kernelBootFiles.initrdImagePath = targetPath
scheduleAdditionalFile = false
} else {
kernelBootFiles.otherFiles = append(kernelBootFiles.otherFiles, targetPath)
scheduleAdditionalFile = false
}

return scheduleAdditionalFile
}

func createIsoFilesStoreFromMountedImage(inputArtifactsStore *IsoArtifactsStore, imageRootDir string, storeDir string) (filesStore *IsoFilesStore, err error) {
Expand All @@ -138,18 +153,13 @@ func createIsoFilesStoreFromMountedImage(inputArtifactsStore *IsoArtifactsStore,
artifactsDir: artifactsDir,
savedConfigsFilePath: filepath.Join(artifactsDir, savedConfigsDir, savedConfigsFileName),
additionalFiles: make(map[string]string),
kernelBootFiles: make(map[string]*KernelBootFiles),
}

// the following files will be re-created - no need to copy them only to
// have them overwritten.
var exclusions []*regexp.Regexp
//
// We will generate a new initrd later. So, we do not copy the initrd.img
// that comes in the input full disk image.
//
exclusions = append(exclusions, regexp.MustCompile(`/boot/initrd\.img.*`))
exclusions = append(exclusions, regexp.MustCompile(`/boot/initramfs-.*\.img.*`))
//
// On full disk images (generated by Mariner toolkit), there are two
// grub.cfg files:
// - <boot partition>/boot/grub2/grub.cfg:
Expand Down Expand Up @@ -195,6 +205,13 @@ func createIsoFilesStoreFromMountedImage(inputArtifactsStore *IsoArtifactsStore,
relativeFilePath := strings.TrimPrefix(sourcePath, imageRootDir)
targetPath := strings.Replace(sourcePath, imageRootDir, filesStore.artifactsDir, -1)

// `scheduleAdditionalFile` indicates whether the file being processed
// now should be captured in the general 'additional' files collection
// or it has been captured in a data structure specific field
// (like filesStore.isoGrubCfgPath) and it will be handled from there.
// 'additional files' is a collection of all the files that need to be
// included in the final output, but we do not have particular interest
// in them (i.e. user files that we do not manipulate - but copy as-is).
scheduleAdditionalFile := true

_, bootFilesConfig, err := getBootArchConfig()
Expand Down Expand Up @@ -237,12 +254,11 @@ func createIsoFilesStoreFromMountedImage(inputArtifactsStore *IsoArtifactsStore,
// We will place the pxe grub config next to the iso grub config.
filesStore.pxeGrubCfgPath = filepath.Join(filepath.Dir(filesStore.isoGrubCfgPath), pxeGrubCfg)
scheduleAdditionalFile = false
}

if strings.HasPrefix(filepath.Base(targetPath), vmLinuzPrefix) {
targetPath = filepath.Join(filepath.Dir(targetPath), "vmlinuz")
filesStore.vmlinuzPath = targetPath
case isoInitrdPath:
filesStore.initrdImagePath = targetPath
scheduleAdditionalFile = false
default:
scheduleAdditionalFile = storeIfKernelSpecificFile(filesStore, targetPath)
}

err = file.NewFileCopyBuilder(sourcePath, targetPath).
Expand Down Expand Up @@ -280,7 +296,7 @@ func createIsoFilesStoreFromMountedImage(inputArtifactsStore *IsoArtifactsStore,
// already. This also ensures that no file from the input iso overwrites
// a newer version that has just been created.

// Copy the addition files from the input iso store
// Copy the additional files from the input iso store
for inputSourceFile, inputTargetFile := range inputArtifactsStore.files.additionalFiles {
found := false
for _, targetFile := range filesStore.additionalFiles {
Expand Down Expand Up @@ -327,15 +343,9 @@ func createIsoFilesStoreFromMountedImage(inputArtifactsStore *IsoArtifactsStore,
func createIsoInfoStoreFromMountedImage(imageRootDir string) (infoStore *IsoInfoStore, err error) {
infoStore = &IsoInfoStore{}

kernelVersion, err := findKernelVersion(imageRootDir)
if err != nil {
return nil, fmt.Errorf("failed to determine kernel version from (%s):\n%w", imageRootDir, err)
}
infoStore.kernelVersion = kernelVersion

chroot := safechroot.NewChroot(imageRootDir, true /*isExistingDir*/)
if chroot == nil {
return nil, fmt.Errorf("failed to create a new chroot object for (%s).", imageRootDir)
return nil, fmt.Errorf("failed to create a new chroot object for (%s)", imageRootDir)
}
defer chroot.Close(true /*leaveOnDisk*/)

Expand Down Expand Up @@ -387,6 +397,7 @@ func createIsoFilesStoreFromIsoImage(isoImageFile, storeDir string) (filesStore
}

filesStore.additionalFiles = make(map[string]string)
filesStore.kernelBootFiles = make(map[string]*KernelBootFiles)

_, bootFilesConfig, err := getBootArchConfig()
if err != nil {
Expand Down Expand Up @@ -429,12 +440,11 @@ func createIsoFilesStoreFromIsoImage(isoImageFile, storeDir string) (filesStore
case savedConfigsFileNamePath:
filesStore.savedConfigsFilePath = isoFile
scheduleAdditionalFile = false
case isoKernelPath:
filesStore.vmlinuzPath = isoFile
scheduleAdditionalFile = false
case isoBootImagePath:
filesStore.isoBootImagePath = isoFile
scheduleAdditionalFile = false
default:
scheduleAdditionalFile = storeIfKernelSpecificFile(filesStore, isoFile)
}

if scheduleAdditionalFile {
Expand All @@ -457,7 +467,6 @@ func createIsoInfoStoreFromIsoImage(savedConfigFile string) (infoStore *IsoInfoS
// since we will not expand the rootfs and inspect its contents to get
// such information.
infoStore = &IsoInfoStore{
kernelVersion: savedConfigs.OS.KernelVersion,
dracutPackageInfo: savedConfigs.OS.DracutPackageInfo,
selinuxPolicyPackageInfo: savedConfigs.OS.SELinuxPolicyPackageInfo,
}
Expand Down Expand Up @@ -524,6 +533,19 @@ func fileExistsToString(filePath string) string {
return "!e " + filePath
}

func dumpKernelFiles(kernelBootFiles *KernelBootFiles) {
if kernelBootFiles == nil {
logger.Log.Debugf("-- -- not defined")
return
}

logger.Log.Debugf("-- -- vmlinuzPath = %s", fileExistsToString(kernelBootFiles.vmlinuzPath))
logger.Log.Debugf("-- -- initrdImagePath = %s", fileExistsToString(kernelBootFiles.initrdImagePath))
for _, otherFile := range kernelBootFiles.otherFiles {
logger.Log.Debugf("-- -- otherFile = %s", fileExistsToString(otherFile))
}
}

func dumpFilesStore(filesStore *IsoFilesStore) {
logger.Log.Debugf("Files Store")
if filesStore == nil {
Expand All @@ -537,7 +559,12 @@ func dumpFilesStore(filesStore *IsoFilesStore) {
logger.Log.Debugf("-- isoGrubCfgPath = %s", fileExistsToString(filesStore.isoGrubCfgPath))
logger.Log.Debugf("-- pxeGrubCfgPath = %s", fileExistsToString(filesStore.pxeGrubCfgPath))
logger.Log.Debugf("-- savedConfigsFilePath = %s", fileExistsToString(filesStore.savedConfigsFilePath))
logger.Log.Debugf("-- vmlinuzPath = %s", fileExistsToString(filesStore.vmlinuzPath))
logger.Log.Debugf("-- kernel file groups")
for key, value := range filesStore.kernelBootFiles {
logger.Log.Debugf("-- -- version = %s", key)
dumpKernelFiles(value)
}

logger.Log.Debugf("-- initrdImagePath = %s", fileExistsToString(filesStore.initrdImagePath))
logger.Log.Debugf("-- squashfsImagePath = %s", fileExistsToString(filesStore.squashfsImagePath))
logger.Log.Debugf("-- additionalFiles =")
Expand All @@ -552,7 +579,6 @@ func dumpInfoStore(infoStore *IsoInfoStore) {
logger.Log.Debugf("-- not defined")
return
}
logger.Log.Debugf("-- kernelVersion = %s", infoStore.kernelVersion)
logger.Log.Debugf("-- seLinuxMode = %s", infoStore.seLinuxMode)
if infoStore.dracutPackageInfo != nil {
logger.Log.Debugf("-- dracut package info = %s", infoStore.dracutPackageInfo.getFullVersionString())
Expand Down
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