Fix runsc restore to be compatible with docker start --checkpoint ...

Change-Id: I02b30de13f1393df66edf8829fedbf32405d18f8
PiperOrigin-RevId: 246621192

runsc/boot/config.go

@@ -213,6 +213,9 @@ type Config struct {
 	// ProfileEnable is set to prepare the sandbox to be profiled.
 	ProfileEnable bool
 
+	// RestoreFile is the path to the saved container image
+	RestoreFile string
+
 	// TestOnlyAllowRunAsCurrentUserWithoutChroot should only be used in
 	// tests. It allows runsc to start the sandbox process as the current
 	// user, and without chrooting the sandbox process. This can be

runsc/boot/controller.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 	"os"
 	"path"
+	"syscall"
 
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"gvisor.googlesource.com/gvisor/pkg/control/server"
@@ -304,12 +305,17 @@ type RestoreOpts struct {
 func (cm *containerManager) Restore(o *RestoreOpts, _ *struct{}) error {
 	log.Debugf("containerManager.Restore")
 
-	var specFile, deviceFile *os.File
+	var specFile *os.File
+	deviceFD := -1
 	switch numFiles := len(o.FilePayload.Files); numFiles {
 	case 2:
-		// The device file is donated to the platform, so don't Close
-		// it here.
-		deviceFile = o.FilePayload.Files[1]
+		var err error
+		// The device file is donated to the platform.
+		// Can't take ownership away from os.File. dup them to get a new FD.
+		deviceFD, err = syscall.Dup(int(o.FilePayload.Files[1].Fd()))
+		if err != nil {
+			return fmt.Errorf("failed to dup file: %v", err)
+		}
 		fallthrough
 	case 1:
 		specFile = o.FilePayload.Files[0]
@@ -320,11 +326,12 @@ func (cm *containerManager) Restore(o *RestoreOpts, _ *struct{}) error {
 		return fmt.Errorf("at most two files may be passed to Restore")
 	}
 
+	networkStack := cm.l.k.NetworkStack()
 	// Destroy the old kernel and create a new kernel.
 	cm.l.k.Pause()
 	cm.l.k.Destroy()
 
-	p, err := createPlatform(cm.l.conf, int(deviceFile.Fd()))
+	p, err := createPlatform(cm.l.conf, deviceFD)
 	if err != nil {
 		return fmt.Errorf("creating platform: %v", err)
 	}
@@ -347,10 +354,6 @@ func (cm *containerManager) Restore(o *RestoreOpts, _ *struct{}) error {
 	fs.SetRestoreEnvironment(*renv)
 
 	// Prepare to load from the state file.
-	networkStack, err := newEmptyNetworkStack(cm.l.conf, k)
-	if err != nil {
-		return fmt.Errorf("creating network: %v", err)
-	}
 	if eps, ok := networkStack.(*epsocket.Stack); ok {
 		stack.StackFromEnv = eps.Stack // FIXME(b/36201077)
 	}

runsc/boot/fs.go

@@ -187,7 +187,7 @@ func compileMounts(spec *specs.Spec) []specs.Mount {
 // createRootMount creates the root filesystem.
 func createRootMount(ctx context.Context, spec *specs.Spec, conf *Config, fds *fdDispenser, mounts []specs.Mount) (*fs.Inode, error) {
 	// First construct the filesystem from the spec.Root.
-	mf := fs.MountSourceFlags{ReadOnly: spec.Root.Readonly}
+	mf := fs.MountSourceFlags{ReadOnly: spec.Root.Readonly || conf.Overlay}
 
 	var (
 		rootInode *fs.Inode
@@ -419,7 +419,7 @@ func mountDevice(m specs.Mount) string {
 // addRestoreMount adds a mount to the MountSources map used for restoring a
 // checkpointed container.
 func addRestoreMount(conf *Config, renv *fs.RestoreEnvironment, m specs.Mount, fds *fdDispenser) error {
-	fsName, opts, _, err := getMountNameAndOptions(conf, m, fds)
+	fsName, opts, useOverlay, err := getMountNameAndOptions(conf, m, fds)
 
 	// Return the error or nil that corresponds to the default case in getMountNameAndOptions.
 	if err != nil {
@@ -436,6 +436,9 @@ func addRestoreMount(conf *Config, renv *fs.RestoreEnvironment, m specs.Mount, f
 		Flags:      mountFlags(m.Options),
 		DataString: strings.Join(opts, ","),
 	}
+	if useOverlay {
+		newMount.Flags.ReadOnly = true
+	}
 	renv.MountSources[fsName] = append(renv.MountSources[fsName], newMount)
 	log.Infof("Added mount at %q: %+v", fsName, newMount)
 	return nil
@@ -453,7 +456,7 @@ func createRestoreEnvironment(spec *specs.Spec, conf *Config, fds *fdDispenser)
 	opts := p9MountOptions(fd, conf.FileAccess)
 
 	mf := fs.MountSourceFlags{}
-	if spec.Root.Readonly {
+	if spec.Root.Readonly || conf.Overlay {
 		mf.ReadOnly = true
 	}
 

runsc/cmd/do.go

@@ -144,7 +144,7 @@ func (c *Do) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) su
 		Fatalf("Error write spec: %v", err)
 	}
 
-	ws, err := container.Run(cid, spec, conf, tmpDir, "", "", "")
+	ws, err := container.Run(cid, spec, conf, tmpDir, "", "", "", false)
 	if err != nil {
 		Fatalf("running container: %v", err)
 	}

runsc/cmd/restore.go

@@ -33,6 +33,9 @@ type Restore struct {
 
 	// imagePath is the path to the saved container image
 	imagePath string
+
+	// detach indicates that runsc has to start a process and exit without waiting it.
+	detach bool
 }
 
 // Name implements subcommands.Command.Name.
@@ -55,10 +58,9 @@ func (*Restore) Usage() string {
 func (r *Restore) SetFlags(f *flag.FlagSet) {
 	r.Create.SetFlags(f)
 	f.StringVar(&r.imagePath, "image-path", "", "directory path to saved container image")
+	f.BoolVar(&r.detach, "detach", false, "detach from the container's process")
 
 	// Unimplemented flags necessary for compatibility with docker.
-	var d bool
-	f.BoolVar(&d, "detach", false, "ignored")
 
 	var nsr bool
 	f.BoolVar(&nsr, "no-subreaper", false, "ignored")
@@ -92,17 +94,9 @@ func (r *Restore) Execute(_ context.Context, f *flag.FlagSet, args ...interface{
 		Fatalf("image-path flag must be provided")
 	}
 
-	restoreFile := filepath.Join(r.imagePath, checkpointFileName)
+	conf.RestoreFile = filepath.Join(r.imagePath, checkpointFileName)
 
-	c, err := container.Load(conf.RootDir, id)
-	if err != nil {
-		Fatalf("loading container: %v", err)
-	}
-	if err := c.Restore(spec, conf, restoreFile); err != nil {
-		Fatalf("restoring container: %v", err)
-	}
-
-	ws, err := c.Wait()
+	ws, err := container.Run(id, spec, conf, bundleDir, r.consoleSocket, r.pidFile, r.userLog, r.detach)
 	if err != nil {
 		Fatalf("running container: %v", err)
 	}

runsc/cmd/run.go

@@ -29,6 +29,9 @@ import (
 type Run struct {
 	// Run flags are a super-set of those for Create.
 	Create
+
+	// detach indicates that runsc has to start a process and exit without waiting it.
+	detach bool
 }
 
 // Name implements subcommands.Command.Name.
@@ -49,6 +52,7 @@ func (*Run) Usage() string {
 
 // SetFlags implements subcommands.Command.SetFlags.
 func (r *Run) SetFlags(f *flag.FlagSet) {
+	f.BoolVar(&r.detach, "detach", false, "detach from the container's process")
 	r.Create.SetFlags(f)
 }
 
@@ -73,7 +77,7 @@ func (r *Run) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) s
 	}
 	specutils.LogSpec(spec)
 
-	ws, err := container.Run(id, spec, conf, bundleDir, r.consoleSocket, r.pidFile, r.userLog)
+	ws, err := container.Run(id, spec, conf, bundleDir, r.consoleSocket, r.pidFile, r.userLog, r.detach)
 	if err != nil {
 		Fatalf("running container: %v", err)
 	}

runsc/container/container.go

@@ -445,6 +445,14 @@ func (c *Container) Restore(spec *specs.Spec, conf *boot.Config, restoreFile str
 		return err
 	}
 
+	// "If any prestart hook fails, the runtime MUST generate an error,
+	// stop and destroy the container" -OCI spec.
+	if c.Spec.Hooks != nil {
+		if err := executeHooks(c.Spec.Hooks.Prestart, c.State()); err != nil {
+			return err
+		}
+	}
+
 	if err := c.Sandbox.Restore(c.ID, spec, conf, restoreFile); err != nil {
 		return err
 	}
@@ -453,7 +461,7 @@ func (c *Container) Restore(spec *specs.Spec, conf *boot.Config, restoreFile str
 }
 
 // Run is a helper that calls Create + Start + Wait.
-func Run(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocket, pidFile, userLog string) (syscall.WaitStatus, error) {
+func Run(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocket, pidFile, userLog string, detach bool) (syscall.WaitStatus, error) {
 	log.Debugf("Run container %q in root dir: %s", id, conf.RootDir)
 	c, err := Create(id, spec, conf, bundleDir, consoleSocket, pidFile, userLog)
 	if err != nil {
@@ -461,10 +469,24 @@ func Run(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocke
 	}
 	// Clean up partially created container if an error ocurrs.
 	// Any errors returned by Destroy() itself are ignored.
-	defer c.Destroy()
+	cu := specutils.MakeCleanup(func() {
+		c.Destroy()
+	})
+	defer cu.Clean()
 
-	if err := c.Start(conf); err != nil {
-		return 0, fmt.Errorf("starting container: %v", err)
+	if conf.RestoreFile != "" {
+		log.Debugf("Restore: %v", conf.RestoreFile)
+		if err := c.Restore(spec, conf, conf.RestoreFile); err != nil {
+			return 0, fmt.Errorf("starting container: %v", err)
+		}
+	} else {
+		if err := c.Start(conf); err != nil {
+			return 0, fmt.Errorf("starting container: %v", err)
+		}
+	}
+	if detach {
+		cu.Release()
+		return 0, nil
 	}
 	return c.Wait()
 }

runsc/container/container_test.go

@@ -210,7 +210,7 @@ func run(spec *specs.Spec, conf *boot.Config) error {
 	defer os.RemoveAll(bundleDir)
 
 	// Create, start and wait for the container.
-	ws, err := Run(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", "")
+	ws, err := Run(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", "", false)
 	if err != nil {
 		return fmt.Errorf("running container: %v", err)
 	}
@@ -416,7 +416,7 @@ func TestExePath(t *testing.T) {
 				t.Fatalf("exec: %s, error setting up container: %v", test.path, err)
 			}
 
-			ws, err := Run(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", "")
+			ws, err := Run(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", "", false)
 
 			os.RemoveAll(rootDir)
 			os.RemoveAll(bundleDir)
@@ -449,7 +449,7 @@ func TestAppExitStatus(t *testing.T) {
 	defer os.RemoveAll(rootDir)
 	defer os.RemoveAll(bundleDir)
 
-	ws, err := Run(testutil.UniqueContainerID(), succSpec, conf, bundleDir, "", "", "")
+	ws, err := Run(testutil.UniqueContainerID(), succSpec, conf, bundleDir, "", "", "", false)
 	if err != nil {
 		t.Fatalf("error running container: %v", err)
 	}
@@ -468,7 +468,7 @@ func TestAppExitStatus(t *testing.T) {
 	defer os.RemoveAll(rootDir2)
 	defer os.RemoveAll(bundleDir2)
 
-	ws, err = Run(testutil.UniqueContainerID(), errSpec, conf, bundleDir2, "", "", "")
+	ws, err = Run(testutil.UniqueContainerID(), errSpec, conf, bundleDir2, "", "", "", false)
 	if err != nil {
 		t.Fatalf("error running container: %v", err)
 	}
@@ -1519,7 +1519,7 @@ func TestUserLog(t *testing.T) {
 	userLog := filepath.Join(dir, "user.log")
 
 	// Create, start and wait for the container.
-	ws, err := Run(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", userLog)
+	ws, err := Run(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", userLog, false)
 	if err != nil {
 		t.Fatalf("error running container: %v", err)
 	}

runsc/test/install.sh

@@ -76,7 +76,8 @@ if [[ ${uninstall} == 0 ]]; then
   sudo -n chmod a+wx "${logdir}"
 
   declare -r args="--debug-log '${logdir}/' --debug --strace --log-packets"
-  sudo -n "${dockercfg}" runtime-add "${runtime}" "${runsc}" ${args}
+  # experimental is needed to checkpoint/restore.
+  sudo -n "${dockercfg}" --experimental=true runtime-add "${runtime}" "${runsc}" ${args}
   sudo -n "${dockercfg}" runtime-add "${runtime}"-kvm "${runsc}" --platform=kvm ${args}
   sudo -n "${dockercfg}" runtime-add "${runtime}"-hostnet "${runsc}" --network=host ${args}
   sudo -n "${dockercfg}" runtime-add "${runtime}"-overlay "${runsc}" --overlay ${args}

runsc/test/integration/integration_test.go

@@ -148,6 +148,50 @@ func TestPauseResume(t *testing.T) {
 	}
 }
 
+func TestCheckpointRestore(t *testing.T) {
+	if !testutil.IsPauseResumeSupported() {
+		t.Log("Pause/resume is not supported, skipping test.")
+		return
+	}
+	if err := testutil.Pull("google/python-hello"); err != nil {
+		t.Fatal("docker pull failed:", err)
+	}
+	d := testutil.MakeDocker("save-restore-test")
+	if err := d.Run("-p", "8080", "google/python-hello"); err != nil {
+		t.Fatalf("docker run failed: %v", err)
+	}
+	defer d.CleanUp()
+
+	if err := d.Checkpoint("test"); err != nil {
+		t.Fatal("docker checkpoint failed:", err)
+	}
+
+	if _, err := d.Wait(30 * time.Second); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := d.Restore("test"); err != nil {
+		t.Fatal("docker restore failed:", err)
+	}
+
+	// Find where port 8080 is mapped to.
+	port, err := d.FindPort(8080)
+	if err != nil {
+		t.Fatal("docker.FindPort(8080) failed:", err)
+	}
+
+	// Wait until it's up and running.
+	if err := testutil.WaitForHTTP(port, 30*time.Second); err != nil {
+		t.Fatal("WaitForHTTP() timeout:", err)
+	}
+
+	// Check if container is working again.
+	client := http.Client{Timeout: time.Duration(2 * time.Second)}
+	if err := httpRequestSucceeds(client, "localhost", port); err != nil {
+		t.Error("http request failed:", err)
+	}
+}
+
 // Create client and server that talk to each other using the local IP.
 func TestConnectToSelf(t *testing.T) {
 	d := testutil.MakeDocker("connect-to-self-test")

runsc/test/testutil/docker.go

@@ -263,6 +263,22 @@ func (d *Docker) Unpause() error {
 	return nil
 }
 
+// Checkpoint calls 'docker checkpoint'.
+func (d *Docker) Checkpoint(name string) error {
+	if _, err := do("checkpoint", "create", d.Name, name); err != nil {
+		return fmt.Errorf("error pausing container %q: %v", d.Name, err)
+	}
+	return nil
+}
+
+// Restore calls 'docker start --checkname [name]'.
+func (d *Docker) Restore(name string) error {
+	if _, err := do("start", "--checkpoint", name, d.Name); err != nil {
+		return fmt.Errorf("error starting container %q: %v", d.Name, err)
+	}
+	return nil
+}
+
 // Remove calls 'docker rm'.
 func (d *Docker) Remove() error {
 	if _, err := do("rm", d.Name); err != nil {

runsc/tools/dockercfg/dockercfg.go

@@ -28,7 +28,8 @@ import (
 )
 
 var (
-	configFile = flag.String("config_file", "/etc/docker/daemon.json", "path to Docker daemon config file")
+	configFile   = flag.String("config_file", "/etc/docker/daemon.json", "path to Docker daemon config file")
+	experimental = flag.Bool("experimental", false, "enable experimental features")
 )
 
 func main() {
@@ -96,6 +97,9 @@ func (r *runtimeAdd) Execute(_ context.Context, f *flag.FlagSet, args ...interfa
 		rts = make(map[string]interface{})
 		c["runtimes"] = rts
 	}
+	if *experimental {
+		c["experimental"] = true
+	}
 	rts[name] = runtime{Path: path, RuntimeArgs: runtimeArgs}
 
 	if err := writeConfig(c, *configFile); err != nil {