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Merge pull request containers#1904 from adrianreber/2024-03-13-common
Added checkpoint specific functions
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,256 @@ | ||
| package crutils | ||
|
|
||
| import ( | ||
| "bytes" | ||
| "errors" | ||
| "fmt" | ||
| "io" | ||
| "os" | ||
| "os/exec" | ||
| "path/filepath" | ||
|
|
||
| metadata "github.com/checkpoint-restore/checkpointctl/lib" | ||
| "github.com/checkpoint-restore/go-criu/v7/stats" | ||
| "github.com/containers/storage/pkg/archive" | ||
| "github.com/opencontainers/selinux/go-selinux/label" | ||
| ) | ||
|
|
||
| // This file mainly exists to make the checkpoint/restore functions | ||
| // available for other users. One possible candidate would be CRI-O. | ||
|
|
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| // CRImportCheckpointWithoutConfig imports the checkpoint archive (input) | ||
| // into the directory destination without "config.dump" and "spec.dump" | ||
| func CRImportCheckpointWithoutConfig(destination, input string) error { | ||
| archiveFile, err := os.Open(input) | ||
| if err != nil { | ||
| return fmt.Errorf("failed to open checkpoint archive %s for import: %w", input, err) | ||
| } | ||
|
|
||
| defer archiveFile.Close() | ||
| options := &archive.TarOptions{ | ||
| ExcludePatterns: []string{ | ||
| // Import everything else besides the container config | ||
| metadata.ConfigDumpFile, | ||
| metadata.SpecDumpFile, | ||
| }, | ||
| } | ||
| if err = archive.Untar(archiveFile, destination, options); err != nil { | ||
| return fmt.Errorf("unpacking of checkpoint archive %s failed: %w", input, err) | ||
| } | ||
|
|
||
| return nil | ||
| } | ||
|
|
||
| // CRImportCheckpointConfigOnly only imports the checkpoint configuration | ||
| // from the checkpoint archive (input) into the directory destination. | ||
| // Only the files "config.dump" and "spec.dump" are extracted. | ||
| func CRImportCheckpointConfigOnly(destination, input string) error { | ||
| archiveFile, err := os.Open(input) | ||
| if err != nil { | ||
| return fmt.Errorf("failed to open checkpoint archive %s for import: %w", input, err) | ||
| } | ||
|
|
||
| defer archiveFile.Close() | ||
| options := &archive.TarOptions{ | ||
| // Here we only need the files config.dump and spec.dump | ||
| ExcludePatterns: []string{ | ||
| "ctr.log", | ||
| "artifacts", | ||
| stats.StatsDump, | ||
| metadata.RootFsDiffTar, | ||
| metadata.DeletedFilesFile, | ||
| metadata.NetworkStatusFile, | ||
| metadata.CheckpointDirectory, | ||
| metadata.CheckpointVolumesDirectory, | ||
| }, | ||
| } | ||
| if err = archive.Untar(archiveFile, destination, options); err != nil { | ||
| return fmt.Errorf("unpacking of checkpoint archive %s failed: %w", input, err) | ||
| } | ||
|
|
||
| return nil | ||
| } | ||
|
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||
| // CRRemoveDeletedFiles loads the list of deleted files and if | ||
| // it exists deletes all files listed. | ||
| func CRRemoveDeletedFiles(id, baseDirectory, containerRootDirectory string) error { | ||
| deletedFiles, _, err := metadata.ReadContainerCheckpointDeletedFiles(baseDirectory) | ||
| if os.IsNotExist(err) { | ||
| // No files to delete. Just return | ||
| return nil | ||
| } | ||
|
|
||
| if err != nil { | ||
| return fmt.Errorf("failed to read deleted files file: %w", err) | ||
| } | ||
|
|
||
| for _, deleteFile := range deletedFiles { | ||
| // Using RemoveAll as deletedFiles, which is generated from 'podman diff' | ||
| // lists completely deleted directories as a single entry: 'D /root'. | ||
| if err := os.RemoveAll(filepath.Join(containerRootDirectory, deleteFile)); err != nil { | ||
| return fmt.Errorf("failed to delete files from container %s during restore: %w", id, err) | ||
| } | ||
| } | ||
|
|
||
| return nil | ||
| } | ||
|
|
||
| // CRApplyRootFsDiffTar applies the tar archive found in baseDirectory with the | ||
| // root file system changes on top of containerRootDirectory | ||
| func CRApplyRootFsDiffTar(baseDirectory, containerRootDirectory string) error { | ||
| rootfsDiffPath := filepath.Join(baseDirectory, metadata.RootFsDiffTar) | ||
| // Only do this if a rootfs-diff.tar actually exists | ||
| rootfsDiffFile, err := os.Open(rootfsDiffPath) | ||
| if err != nil { | ||
| if errors.Is(err, os.ErrNotExist) { | ||
| return nil | ||
| } | ||
| return fmt.Errorf("failed to open root file-system diff file: %w", err) | ||
| } | ||
| defer rootfsDiffFile.Close() | ||
|
|
||
| if err := archive.Untar(rootfsDiffFile, containerRootDirectory, nil); err != nil { | ||
| return fmt.Errorf("failed to apply root file-system diff file %s: %w", rootfsDiffPath, err) | ||
| } | ||
|
|
||
| return nil | ||
| } | ||
|
|
||
| // CRCreateRootFsDiffTar goes through the 'changes' and can create two files: | ||
| // * metadata.RootFsDiffTar will contain all new and changed files | ||
| // * metadata.DeletedFilesFile will contain a list of deleted files | ||
| // With these two files it is possible to restore the container file system to the same | ||
| // state it was during checkpointing. | ||
| // Changes to directories (owner, mode) are not handled. | ||
| func CRCreateRootFsDiffTar(changes *[]archive.Change, mountPoint, destination string) (includeFiles []string, err error) { | ||
| if len(*changes) == 0 { | ||
| return includeFiles, nil | ||
| } | ||
|
|
||
| var rootfsIncludeFiles []string | ||
| var deletedFiles []string | ||
|
|
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| rootfsDiffPath := filepath.Join(destination, metadata.RootFsDiffTar) | ||
|
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||
| for _, file := range *changes { | ||
| if file.Kind == archive.ChangeAdd { | ||
| rootfsIncludeFiles = append(rootfsIncludeFiles, file.Path) | ||
| continue | ||
| } | ||
| if file.Kind == archive.ChangeDelete { | ||
| deletedFiles = append(deletedFiles, file.Path) | ||
| continue | ||
| } | ||
| fileName, err := os.Stat(file.Path) | ||
| if err != nil { | ||
| continue | ||
| } | ||
| if !fileName.IsDir() && file.Kind == archive.ChangeModify { | ||
| rootfsIncludeFiles = append(rootfsIncludeFiles, file.Path) | ||
| continue | ||
| } | ||
| } | ||
|
|
||
| if len(rootfsIncludeFiles) > 0 { | ||
| rootfsTar, err := archive.TarWithOptions(mountPoint, &archive.TarOptions{ | ||
| Compression: archive.Uncompressed, | ||
| IncludeSourceDir: true, | ||
| IncludeFiles: rootfsIncludeFiles, | ||
| }) | ||
| if err != nil { | ||
| return includeFiles, fmt.Errorf("exporting root file-system diff to %q: %w", rootfsDiffPath, err) | ||
| } | ||
| rootfsDiffFile, err := os.Create(rootfsDiffPath) | ||
| if err != nil { | ||
| return includeFiles, fmt.Errorf("creating root file-system diff file %q: %w", rootfsDiffPath, err) | ||
| } | ||
| defer rootfsDiffFile.Close() | ||
| if _, err = io.Copy(rootfsDiffFile, rootfsTar); err != nil { | ||
| return includeFiles, err | ||
| } | ||
|
|
||
| includeFiles = append(includeFiles, metadata.RootFsDiffTar) | ||
| } | ||
|
|
||
| if len(deletedFiles) == 0 { | ||
| return includeFiles, nil | ||
| } | ||
|
|
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| if _, err := metadata.WriteJSONFile(deletedFiles, destination, metadata.DeletedFilesFile); err != nil { | ||
| return includeFiles, nil | ||
| } | ||
|
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| includeFiles = append(includeFiles, metadata.DeletedFilesFile) | ||
|
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| return includeFiles, nil | ||
| } | ||
|
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| // CRCreateFileWithLabel creates an empty file and sets the corresponding ('fileLabel') | ||
| // SELinux label on the file. | ||
| // This is necessary for CRIU log files because CRIU infects the processes in | ||
| // the container with a 'parasite' and this will also try to write to the log files | ||
| // from the context of the container processes. | ||
| func CRCreateFileWithLabel(directory, fileName, fileLabel string) error { | ||
| logFileName := filepath.Join(directory, fileName) | ||
|
|
||
| logFile, err := os.OpenFile(logFileName, os.O_CREATE, 0o600) | ||
| if err != nil { | ||
| return fmt.Errorf("failed to create file %q: %w", logFileName, err) | ||
| } | ||
| defer logFile.Close() | ||
| if err = label.SetFileLabel(logFileName, fileLabel); err != nil { | ||
| return fmt.Errorf("failed to label file %q: %w", logFileName, err) | ||
| } | ||
|
|
||
| return nil | ||
| } | ||
|
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||
| // CRRuntimeSupportsCheckpointRestore tests if the given runtime at 'runtimePath' | ||
| // supports checkpointing. The checkpoint restore interface has no definition | ||
| // but crun implements all commands just as runc does. What runc does is the | ||
| // official definition of the checkpoint/restore interface. | ||
| func CRRuntimeSupportsCheckpointRestore(runtimePath string) bool { | ||
| // Check if the runtime implements checkpointing. Currently only | ||
| // runc's and crun's checkpoint/restore implementation is supported. | ||
| cmd := exec.Command(runtimePath, "checkpoint", "--help") | ||
| if err := cmd.Start(); err != nil { | ||
| return false | ||
| } | ||
| if err := cmd.Wait(); err == nil { | ||
| return true | ||
| } | ||
| return false | ||
| } | ||
|
|
||
| // CRRuntimeSupportsCheckpointRestore tests if the runtime at 'runtimePath' | ||
| // supports restoring into existing Pods. The runtime needs to support | ||
| // the CRIU option --lsm-mount-context and the existence of this is checked | ||
| // by this function. In addition it is necessary to at least have CRIU 3.16. | ||
| func CRRuntimeSupportsPodCheckpointRestore(runtimePath string) bool { | ||
| cmd := exec.Command(runtimePath, "restore", "--lsm-mount-context") | ||
| out, _ := cmd.CombinedOutput() | ||
| return bytes.Contains(out, []byte("flag needs an argument")) | ||
| } | ||
|
|
||
| // CRGetRuntimeFromArchive extracts the checkpoint metadata from the | ||
| // given checkpoint archive and returns the runtime used to create | ||
| // the given checkpoint archive. | ||
| func CRGetRuntimeFromArchive(input string) (*string, error) { | ||
| dir, err := os.MkdirTemp("", "checkpoint") | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| defer os.RemoveAll(dir) | ||
|
|
||
| if err := CRImportCheckpointConfigOnly(dir, input); err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| // Load config.dump from temporary directory | ||
| ctrConfig := new(metadata.ContainerConfig) | ||
| if _, err = metadata.ReadJSONFile(ctrConfig, dir, metadata.ConfigDumpFile); err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| return &ctrConfig.OCIRuntime, nil | ||
| } |
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