pptx704
a1bd439c75
Implement full snapshot lifecycle: pause (snapshot + free resources), resume (UFFD-based lazy restore), and named snapshot templates that can spawn new sandboxes from frozen VM state. Key changes: - Snapshot header system with generational diff mapping (inspired by e2b) - UFFD server for lazy page fault handling during snapshot restore - Stable rootfs symlink path (/tmp/fc-vm/) for snapshot compatibility - Templates DB table and CRUD API endpoints (POST/GET/DELETE /v1/snapshots) - CreateSnapshot/DeleteSnapshot RPCs in hostagent proto - Reconciler excludes paused sandboxes (expected absent from host agent) - Snapshot templates lock vcpus/memory to baked-in values - Proper cleanup of uffd sockets and pause snapshot files on destroy
102 lines
2.6 KiB
Go
102 lines
2.6 KiB
Go
package snapshot
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import (
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"fmt"
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"io/fs"
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"os"
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"path/filepath"
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)
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const (
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SnapFileName = "snapfile"
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MemDiffName = "memfile"
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MemHeaderName = "memfile.header"
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RootfsFileName = "rootfs.ext4"
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)
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// DirPath returns the snapshot directory for a given name.
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func DirPath(baseDir, name string) string {
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return filepath.Join(baseDir, name)
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}
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// SnapPath returns the path to the VM state snapshot file.
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func SnapPath(baseDir, name string) string {
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return filepath.Join(DirPath(baseDir, name), SnapFileName)
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}
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// MemDiffPath returns the path to the compact memory diff file.
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func MemDiffPath(baseDir, name string) string {
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return filepath.Join(DirPath(baseDir, name), MemDiffName)
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}
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// MemHeaderPath returns the path to the memory mapping header file.
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func MemHeaderPath(baseDir, name string) string {
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return filepath.Join(DirPath(baseDir, name), MemHeaderName)
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}
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// RootfsPath returns the path to the rootfs image.
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func RootfsPath(baseDir, name string) string {
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return filepath.Join(DirPath(baseDir, name), RootfsFileName)
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}
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// Exists reports whether a complete snapshot exists (all required files present).
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func Exists(baseDir, name string) bool {
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dir := DirPath(baseDir, name)
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for _, f := range []string{SnapFileName, MemDiffName, MemHeaderName, RootfsFileName} {
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if _, err := os.Stat(filepath.Join(dir, f)); err != nil {
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return false
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}
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}
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return true
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}
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// IsTemplate reports whether a template image directory exists (has rootfs.ext4).
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func IsTemplate(baseDir, name string) bool {
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_, err := os.Stat(filepath.Join(DirPath(baseDir, name), RootfsFileName))
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return err == nil
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}
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// IsSnapshot reports whether a directory is a snapshot (has all snapshot files).
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func IsSnapshot(baseDir, name string) bool {
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return Exists(baseDir, name)
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}
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// EnsureDir creates the snapshot directory if it doesn't exist.
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func EnsureDir(baseDir, name string) error {
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dir := DirPath(baseDir, name)
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if err := os.MkdirAll(dir, 0755); err != nil {
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return fmt.Errorf("create snapshot dir %s: %w", dir, err)
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}
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return nil
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}
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// Remove deletes the entire snapshot directory.
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func Remove(baseDir, name string) error {
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return os.RemoveAll(DirPath(baseDir, name))
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}
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// DirSize returns the total byte size of all files in the snapshot directory.
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func DirSize(baseDir, name string) (int64, error) {
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var total int64
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dir := DirPath(baseDir, name)
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err := filepath.WalkDir(dir, func(_ string, d fs.DirEntry, err error) error {
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if err != nil {
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return err
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}
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if d.IsDir() {
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return nil
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}
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info, err := d.Info()
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if err != nil {
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return err
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}
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total += info.Size()
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return nil
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})
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if err != nil {
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return 0, fmt.Errorf("calculate snapshot size: %w", err)
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}
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return total, nil
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}
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