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Add state pattern for container state transition 

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Add state status() method

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Allow multiple checkpoint on restore

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Handle leave-running state

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Fix state transitions for inprocess

Because the tests use libcontainer in process between the various states
we need to ensure that that usecase works as well as the out of process
one.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Remove isDestroyed method

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Handling Pausing from freezer state

Signed-off-by: Rajasekaran <rajasec79@gmail.com>

freezer status

Signed-off-by: Rajasekaran <rajasec79@gmail.com>

Fixing review comments

Signed-off-by: Rajasekaran <rajasec79@gmail.com>

Added comment when freezer not available

Signed-off-by: Rajasekaran <rajasec79@gmail.com>
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Conflicts:
	libcontainer/container_linux.go

Change checkFreezer logic to isPaused()

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Remove state base and factor out destroy func

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Add unit test for state transitions

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This commit is contained in:
Michael Crosby 2015-10-02 11:16:50 -07:00
parent 9d6ce7168a
commit 4415446c32
10 changed files with 435 additions and 131 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
checkpoint.go
View File

@ -30,14 +30,8 @@ var checkpointCommand = cli.Command{
if err != nil {
fatal(err)
}
defer destroy(container)
options := criuOptions(context)
status, err := container.Status()
if err != nil {
fatal(err)
}
if status == libcontainer.Checkpointed {
fatal(fmt.Errorf("Container with id %s already checkpointed", context.GlobalString("id")))
}
// these are the mandatory criu options for a container
setPageServer(context, options)
setManageCgroupsMode(context, options)

17
libcontainer/container.go
View File

@ -30,6 +30,23 @@ const (
Destroyed
)
func (s Status) String() string {
switch s {
case Running:
return "running"
case Pausing:
return "pausing"
case Paused:
return "paused"
case Checkpointed:
return "checkpointed"
case Destroyed:
return "destroyed"
default:
return "undefined"
}
}
// BaseState represents the platform agnostic pieces relating to a
// running container's state
type BaseState struct {

177
libcontainer/container_linux.go
View File

@ -37,6 +37,7 @@ type linuxContainer struct {
criuPath string
m sync.Mutex
criuVersion int
state containerState
}
// State represents a running container's state
@ -183,7 +184,14 @@ func (c *linuxContainer) Start(process *Process) error {
return newSystemError(err)
}
if doInit {
c.updateState(parent)
if err := c.updateState(parent); err != nil {
return err
}
} else {
c.state.transition(&nullState{
c: c,
s: Running,
})
}
if c.config.Hooks != nil {
s := configs.HookState{
@ -320,48 +328,29 @@ func newPipe() (parent *os.File, child *os.File, err error) {
func (c *linuxContainer) Destroy() error {
c.m.Lock()
defer c.m.Unlock()
status, err := c.currentStatus()
if err != nil {
return err
}
if status != Destroyed {
return newGenericError(fmt.Errorf("container is not destroyed"), ContainerNotStopped)
}
if !c.config.Namespaces.Contains(configs.NEWPID) {
if err := killCgroupProcesses(c.cgroupManager); err != nil {
logrus.Warn(err)
}
}
err = c.cgroupManager.Destroy()
if rerr := os.RemoveAll(c.root); err == nil {
err = rerr
}
c.initProcess = nil
if c.config.Hooks != nil {
s := configs.HookState{
Version: c.config.Version,
ID: c.id,
Root: c.config.Rootfs,
}
for _, hook := range c.config.Hooks.Poststop {
if err := hook.Run(s); err != nil {
return err
}
}
}
return err
return c.state.destroy()
}
func (c *linuxContainer) Pause() error {
c.m.Lock()
defer c.m.Unlock()
return c.cgroupManager.Freeze(configs.Frozen)
if err := c.cgroupManager.Freeze(configs.Frozen); err != nil {
return err
}
return c.state.transition(&pausedState{
c: c,
})
}
func (c *linuxContainer) Resume() error {
c.m.Lock()
defer c.m.Unlock()
return c.cgroupManager.Freeze(configs.Thawed)
if err := c.cgroupManager.Freeze(configs.Thawed); err != nil {
return err
}
return c.state.transition(&runningState{
c: c,
})
}
func (c *linuxContainer) NotifyOOM() (<-chan struct{}, error) {
@ -459,7 +448,7 @@ func (c *linuxContainer) Checkpoint(criuOpts *CriuOpts) error {
}
if criuOpts.ImagesDirectory == "" {
criuOpts.ImagesDirectory = filepath.Join(c.root, "criu.image")
return fmt.Errorf("invalid directory to save checkpoint")
}
// Since a container can be C/R'ed multiple times,
@ -578,11 +567,9 @@ func (c *linuxContainer) addCriuRestoreMount(req *criurpc.CriuReq, m *configs.Mo
func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
c.m.Lock()
defer c.m.Unlock()
if err := c.checkCriuVersion("1.5.2"); err != nil {
return err
}
if criuOpts.WorkDirectory == "" {
criuOpts.WorkDirectory = filepath.Join(c.root, "criu.work")
}
@ -591,22 +578,19 @@ func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
if err := os.Mkdir(criuOpts.WorkDirectory, 0655); err != nil && !os.IsExist(err) {
return err
}
workDir, err := os.Open(criuOpts.WorkDirectory)
if err != nil {
return err
}
defer workDir.Close()
if criuOpts.ImagesDirectory == "" {
criuOpts.ImagesDirectory = filepath.Join(c.root, "criu.image")
return fmt.Errorf("invalid directory to restore checkpoint")
}
imageDir, err := os.Open(criuOpts.ImagesDirectory)
if err != nil {
return err
}
defer imageDir.Close()
// CRIU has a few requirements for a root directory:
// * it must be a mount point
// * its parent must not be overmounted
@ -617,18 +601,15 @@ func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
return err
}
defer os.Remove(root)
root, err = filepath.EvalSymlinks(root)
if err != nil {
return err
}
err = syscall.Mount(c.config.Rootfs, root, "", syscall.MS_BIND|syscall.MS_REC, "")
if err != nil {
return err
}
defer syscall.Unmount(root, syscall.MNT_DETACH)
t := criurpc.CriuReqType_RESTORE
req := &criurpc.CriuReq{
Type: &t,
@ -696,15 +677,13 @@ func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
fds []string
fdJSON []byte
)
if fdJSON, err = ioutil.ReadFile(filepath.Join(criuOpts.ImagesDirectory, descriptorsFilename)); err != nil {
return err
}
if err = json.Unmarshal(fdJSON, &fds); err != nil {
if err := json.Unmarshal(fdJSON, &fds); err != nil {
return err
}
for i := range fds {
if s := fds[i]; strings.Contains(s, "pipe:") {
inheritFd := new(criurpc.InheritFd)
@ -713,12 +692,7 @@ func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
req.Opts.InheritFd = append(req.Opts.InheritFd, inheritFd)
}
}
err = c.criuSwrk(process, req, criuOpts, true)
if err != nil {
return err
}
return nil
return c.criuSwrk(process, req, criuOpts, true)
}
func (c *linuxContainer) criuApplyCgroups(pid int, req *criurpc.CriuReq) error {
@ -913,82 +887,123 @@ func (c *linuxContainer) criuNotifications(resp *criurpc.CriuResp, process *Proc
if notify == nil {
return fmt.Errorf("invalid response: %s", resp.String())
}
switch {
case notify.GetScript() == "post-dump":
if !opts.LeaveRunning {
f, err := os.Create(filepath.Join(c.root, "checkpoint"))
if err != nil {
return err
}
f.Close()
f, err := os.Create(filepath.Join(c.root, "checkpoint"))
if err != nil {
return err
}
break
f.Close()
case notify.GetScript() == "network-unlock":
if err := unlockNetwork(c.config); err != nil {
return err
}
break
case notify.GetScript() == "network-lock":
if err := lockNetwork(c.config); err != nil {
return err
}
break
case notify.GetScript() == "post-restore":
pid := notify.GetPid()
r, err := newRestoredProcess(int(pid), fds)
if err != nil {
return err
}
// TODO: crosbymichael restore previous process information by saving the init process information in
// the container's state file or separate process state files.
process.ops = r
if err := c.state.transition(&restoredState{
imageDir: opts.ImagesDirectory,
c: c,
}); err != nil {
return err
}
if err := c.updateState(r); err != nil {
return err
}
process.ops = r
break
if err := os.Remove(filepath.Join(c.root, "checkpoint")); err != nil {
if !os.IsNotExist(err) {
logrus.Error(err)
}
}
}
return nil
}
func (c *linuxContainer) updateState(process parentProcess) error {
c.initProcess = process
if err := c.refreshState(); err != nil {
return err
}
state, err := c.currentState()
if err != nil {
return err
}
return c.saveState(state)
}
func (c *linuxContainer) saveState(s *State) error {
f, err := os.Create(filepath.Join(c.root, stateFilename))
if err != nil {
return err
}
defer f.Close()
os.Remove(filepath.Join(c.root, "checkpoint"))
return json.NewEncoder(f).Encode(state)
return json.NewEncoder(f).Encode(s)
}
func (c *linuxContainer) deleteState() error {
return os.Remove(filepath.Join(c.root, stateFilename))
}
func (c *linuxContainer) currentStatus() (Status, error) {
if _, err := os.Stat(filepath.Join(c.root, "checkpoint")); err == nil {
return Checkpointed, nil
if err := c.refreshState(); err != nil {
return -1, err
}
return c.state.status(), nil
}
// refreshState needs to be called to verify that the current state on the
// container is what is true. Because consumers of libcontainer can use it
// out of process we need to verify the container's status based on runtime
// information and not rely on our in process info.
func (c *linuxContainer) refreshState() error {
paused, err := c.isPaused()
if err != nil {
return err
}
if paused {
return c.state.transition(&pausedState{c: c})
}
running, err := c.isRunning()
if err != nil {
return err
}
if running {
return c.state.transition(&runningState{c: c})
}
return c.state.transition(&stoppedState{c: c})
}
func (c *linuxContainer) isRunning() (bool, error) {
if c.initProcess == nil {
return Destroyed, nil
return false, nil
}
// return Running if the init process is alive
if err := syscall.Kill(c.initProcess.pid(), 0); err != nil {
if err == syscall.ESRCH {
return Destroyed, nil
return false, nil
}
return 0, newSystemError(err)
return false, newSystemError(err)
}
if c.config.Cgroups != nil && c.config.Cgroups.Resources != nil && c.config.Cgroups.Resources.Freezer == configs.Frozen {
return Paused, nil
return true, nil
}
func (c *linuxContainer) isPaused() (bool, error) {
data, err := ioutil.ReadFile(filepath.Join(c.cgroupManager.GetPaths()["freezer"], "freezer.state"))
if err != nil {
if os.IsNotExist(err) {
return false, nil
}
return false, newSystemError(err)
}
return Running, nil
return bytes.Equal(bytes.TrimSpace(data), []byte("FROZEN")), nil
}
func (c *linuxContainer) currentState() (*State, error) {

1
libcontainer/container_linux_test.go
View File

@ -161,6 +161,7 @@ func TestGetContainerState(t *testing.T) {
},
},
}
container.state = &nullState{c: container}
state, err := container.State()
if err != nil {
t.Fatal(err)

12
libcontainer/factory_linux.go
View File

@ -166,7 +166,7 @@ func (l *LinuxFactory) Create(id string, config *configs.Config) (Container, err
if err := os.MkdirAll(containerRoot, 0700); err != nil {
return nil, newGenericError(err, SystemError)
}
return &linuxContainer{
c := &linuxContainer{
id: id,
root: containerRoot,
config: config,
@ -174,7 +174,9 @@ func (l *LinuxFactory) Create(id string, config *configs.Config) (Container, err
initArgs: l.InitArgs,
criuPath: l.CriuPath,
cgroupManager: l.NewCgroupsManager(config.Cgroups, nil),
}, nil
}
c.state = &stoppedState{c: c}
return c, nil
}
func (l *LinuxFactory) Load(id string) (Container, error) {
@ -191,7 +193,7 @@ func (l *LinuxFactory) Load(id string) (Container, error) {
processStartTime: state.InitProcessStartTime,
fds: state.ExternalDescriptors,
}
return &linuxContainer{
c := &linuxContainer{
initProcess: r,
id: id,
config: &state.Config,
@ -200,7 +202,9 @@ func (l *LinuxFactory) Load(id string) (Container, error) {
criuPath: l.CriuPath,
cgroupManager: l.NewCgroupsManager(state.Config.Cgroups, state.CgroupPaths),
root: containerRoot,
}, nil
}
c.state = &nullState{c: c}
return c, nil
}
func (l *LinuxFactory) Type() string {

6
libcontainer/integration/checkpoint_test.go
View File

@ -128,8 +128,8 @@ func TestCheckpoint(t *testing.T) {
t.Fatal(err)
}
if state != libcontainer.Checkpointed {
t.Fatal("Unexpected state: ", state)
if state != libcontainer.Running {
t.Fatal("Unexpected state checkpoint: ", state)
}
stdinW.Close()
@ -167,7 +167,7 @@ func TestCheckpoint(t *testing.T) {
t.Fatal(err)
}
if state != libcontainer.Running {
t.Fatal("Unexpected state: ", state)
t.Fatal("Unexpected restore state: ", state)
}
pid, err = restoreProcessConfig.Pid()

217
libcontainer/state_linux.go Normal file
View File

@ -0,0 +1,217 @@
// +build linux
package libcontainer
import (
"fmt"
"os"
"path/filepath"
"github.com/Sirupsen/logrus"
"github.com/opencontainers/runc/libcontainer/configs"
)
func newStateTransitionError(from, to containerState) error {
return &stateTransitionError{
From: from.status().String(),
To: to.status().String(),
}
}
// stateTransitionError is returned when an invalid state transition happens from one
// state to another.
type stateTransitionError struct {
From string
To string
}
func (s *stateTransitionError) Error() string {
return fmt.Sprintf("invalid state transition from %s to %s", s.From, s.To)
}
type containerState interface {
transition(containerState) error
destroy() error
status() Status
}
func destroy(c *linuxContainer) error {
if !c.config.Namespaces.Contains(configs.NEWPID) {
if err := killCgroupProcesses(c.cgroupManager); err != nil {
logrus.Warn(err)
}
}
err := c.cgroupManager.Destroy()
if rerr := os.RemoveAll(c.root); err == nil {
err = rerr
}
c.initProcess = nil
if herr := runPoststopHooks(c); err == nil {
err = herr
}
return err
}
func runPoststopHooks(c *linuxContainer) error {
if c.config.Hooks != nil {
s := configs.HookState{
Version: c.config.Version,
ID: c.id,
Root: c.config.Rootfs,
}
for _, hook := range c.config.Hooks.Poststop {
if err := hook.Run(s); err != nil {
return err
}
}
}
return nil
}
// stoppedState represents a container is a stopped/destroyed state.
type stoppedState struct {
c *linuxContainer
}
func (b *stoppedState) status() Status {
return Destroyed
}
func (b *stoppedState) transition(s containerState) error {
switch s.(type) {
case *runningState:
b.c.state = s
return nil
case *restoredState:
b.c.state = s
return nil
case *stoppedState:
return nil
}
return newStateTransitionError(b, s)
}
func (b *stoppedState) destroy() error {
return destroy(b.c)
}
// runningState represents a container that is currently running.
type runningState struct {
c *linuxContainer
}
func (r *runningState) status() Status {
return Running
}
func (r *runningState) transition(s containerState) error {
switch s.(type) {
case *stoppedState:
running, err := r.c.isRunning()
if err != nil {
return err
}
if running {
return newGenericError(fmt.Errorf("container still running"), ContainerNotStopped)
}
r.c.state = s
return nil
case *pausedState:
r.c.state = s
return nil
case *runningState, *nullState:
return nil
}
return newStateTransitionError(r, s)
}
func (r *runningState) destroy() error {
running, err := r.c.isRunning()
if err != nil {
return err
}
if running {
return newGenericError(fmt.Errorf("container is not destroyed"), ContainerNotStopped)
}
return destroy(r.c)
}
// pausedState represents a container that is currently pause. It cannot be destroyed in a
// paused state and must transition back to running first.
type pausedState struct {
c *linuxContainer
}
func (p *pausedState) status() Status {
return Paused
}
func (p *pausedState) transition(s containerState) error {
switch s.(type) {
case *runningState:
p.c.state = s
return nil
case *pausedState:
return nil
}
return newStateTransitionError(p, s)
}
func (p *pausedState) destroy() error {
return newGenericError(fmt.Errorf("container is paused"), ContainerPaused)
}
// restoredState is the same as the running state but also has accociated checkpoint
// information that maybe need destroyed when the container is stopped and destory is called.
type restoredState struct {
imageDir string
c *linuxContainer
}
func (r *restoredState) status() Status {
return Running
}
func (r *restoredState) transition(s containerState) error {
switch s.(type) {
case *stoppedState:
return nil
case *runningState:
return nil
}
return newStateTransitionError(r, s)
}
func (r *restoredState) destroy() error {
if _, err := os.Stat(filepath.Join(r.c.root, "checkpoint")); err != nil {
if !os.IsNotExist(err) {
return err
}
}
return destroy(r.c)
}
// nullState is used whenever a container is restored, loaded, or setting additional
// processes inside and it should not be destroyed when it is exiting.
type nullState struct {
c *linuxContainer
s Status
}
func (n *nullState) status() Status {
return n.s
}
func (n *nullState) transition(s containerState) error {
switch s.(type) {
case *restoredState:
n.c.state = s
default:
// do nothing for null states
}
return nil
}
func (n *nullState) destroy() error {
return nil
}

85
libcontainer/state_linux_test.go Normal file
View File

@ -0,0 +1,85 @@
// +build linux
package libcontainer
import "testing"
func TestStateStatus(t *testing.T) {
states := map[containerState]Status{
&stoppedState{}: Destroyed,
&runningState{}: Running,
&restoredState{}: Running,
&pausedState{}: Paused,
}
for s, status := range states {
if s.status() != status {
t.Fatalf("state returned %s but expected %s", s.status(), status)
}
}
}
func isStateTransitionError(err error) bool {
_, ok := err.(*stateTransitionError)
return ok
}
func TestStoppedStateTransition(t *testing.T) {
s := &stoppedState{c: &linuxContainer{}}
valid := []containerState{
&stoppedState{},
&runningState{},
&restoredState{},
}
for _, v := range valid {
if err := s.transition(v); err != nil {
t.Fatal(err)
}
}
err := s.transition(&pausedState{})
if err == nil {
t.Fatal("transition to paused state should fail")
}
if !isStateTransitionError(err) {
t.Fatal("expected stateTransitionError")
}
}
func TestPausedStateTransition(t *testing.T) {
s := &pausedState{c: &linuxContainer{}}
valid := []containerState{
&pausedState{},
&runningState{},
}
for _, v := range valid {
if err := s.transition(v); err != nil {
t.Fatal(err)
}
}
err := s.transition(&stoppedState{})
if err == nil {
t.Fatal("transition to stopped state should fail")
}
if !isStateTransitionError(err) {
t.Fatal("expected stateTransitionError")
}
}
func TestRestoredStateTransition(t *testing.T) {
s := &restoredState{c: &linuxContainer{}}
valid := []containerState{
&stoppedState{},
&runningState{},
}
for _, v := range valid {
if err := s.transition(v); err != nil {
t.Fatal(err)
}
}
err := s.transition(&nullState{})
if err == nil {
t.Fatal("transition to null state should fail")
}
if !isStateTransitionError(err) {
t.Fatal("expected stateTransitionError")
}
}

35
restore.go
View File

@ -5,7 +5,6 @@ package main
import (
"fmt"
"os"
"path/filepath"
"github.com/Sirupsen/logrus"
"github.com/codegangsta/cli"
@ -109,24 +108,12 @@ func restoreContainer(context *cli.Context, spec *specs.LinuxSpec, config *confi
// ensure that the container is always removed if we were the process
// that created it.
defer func() {
if err != nil {
return
}
status, err := container.Status()
if err != nil {
logrus.Error(err)
}
if status != libcontainer.Checkpointed {
if err := container.Destroy(); err != nil {
logrus.Error(err)
}
if err := os.RemoveAll(options.ImagesDirectory); err != nil {
logrus.Error(err)
}
}
}()
process := &libcontainer.Process{}
defer destroy(container)
process := &libcontainer.Process{
Stdin: os.Stdin,
Stdout: os.Stdout,
Stderr: os.Stderr,
}
tty, err := newTty(spec.Process.Terminal, process, rootuid)
if err != nil {
return -1, err
@ -134,16 +121,6 @@ func restoreContainer(context *cli.Context, spec *specs.LinuxSpec, config *confi
handler := newSignalHandler(tty)
defer handler.Close()
if err := container.Restore(process, options); err != nil {
cstatus, cerr := container.Status()
if cerr != nil {
logrus.Error(cerr)
}
if cstatus == libcontainer.Destroyed {
dest := filepath.Join(context.GlobalString("root"), context.GlobalString("id"))
if errVal := os.RemoveAll(dest); errVal != nil {
logrus.Error(errVal)
}
}
return -1, err
}
return handler.forward(process)

8
start.go
View File

@ -142,13 +142,7 @@ func setupSocketActivation(spec *specs.LinuxSpec, listenFds string) {
}
func destroy(container libcontainer.Container) {
status, err := container.Status()
if err != nil {
if err := container.Destroy(); err != nil {
logrus.Error(err)
}
if status != libcontainer.Checkpointed {
if err := container.Destroy(); err != nil {
logrus.Error(err)
}
}
}