Implement live restore with shim

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

example/main.go

@@ -15,6 +15,33 @@ import (
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 )
 
+func reloadContainer() error {
+	// create a new runtime runtime that implements the ExecutionDriver interface
+	runtime, err := shim.Load("/run/cshim/test")
+	if err != nil {
+		return err
+	}
+	dockerContainer := &testConfig{}
+	container, err := containerkit.LoadContainer(dockerContainer, runtime)
+	if err != nil {
+		return err
+	}
+	// wait for it to exit and get the exit status
+	logrus.Info("wait container")
+	status, err := container.Wait()
+	if err != nil {
+		return err
+	}
+
+	// delete the container after it is done
+	logrus.Info("delete container")
+	if container.Delete(); err != nil {
+		return err
+	}
+	logrus.Infof("exit status %d", status)
+	return nil
+}
+
 func runContainer() error {
 	// create a new runtime runtime that implements the ExecutionDriver interface
 	runtime, err := shim.New(shim.Opts{
@@ -84,9 +111,7 @@ func runContainer() error {
 	}
 
 	if load {
-		if container, err = containerkit.LoadContainer(dockerContainer, runtime); err != nil {
-			return err
-		}
+		return nil
 	}
 
 	// wait for it to exit and get the exit status
@@ -106,18 +131,26 @@ func runContainer() error {
 }
 
 var (
-	exec int
-	load bool
+	exec   int
+	load   bool
+	reload bool
 )
 
 // "Hooks do optional work. Drivers do mandatory work"
 func main() {
 	flag.IntVar(&exec, "exec", 0, "run n number of execs")
 	flag.BoolVar(&load, "load", false, "reload the container")
+	flag.BoolVar(&reload, "reload", false, "reload the container live")
 	flag.Parse()
 	if err := osutils.SetSubreaper(1); err != nil {
 		logrus.Fatal(err)
 	}
+	if reload {
+		if err := reloadContainer(); err != nil {
+			logrus.Fatal(err)
+		}
+		return
+	}
 	if err := runContainer(); err != nil {
 		logrus.Fatal(err)
 	}

oci/oci.go

@@ -54,6 +54,10 @@ func (r *OCIRuntime) Args() []string {
 	return r.args
 }
 
+func (r *OCIRuntime) Root() string {
+	return r.root
+}
+
 func (r *OCIRuntime) Create(c *containerkit.Container) (containerkit.ProcessDelegate, error) {
 	pidFile := fmt.Sprintf("%s/%s.pid", filepath.Join(r.root, c.ID()), "init")
 	cmd := r.Command("create", "--pid-file", pidFile, "--bundle", c.Path(), c.ID())

shim/process.go

@@ -184,6 +184,7 @@ func (p *process) UnmarshalJSON(b []byte) error {
 	p.stderr = ps.Stderr
 	p.root = ps.Root
 	p.startTime = ps.StartTime
+	p.done = make(chan struct{})
 	pid, err := readPid(filepath.Join(p.root, "pid"))
 	if err != nil {
 		return err

shim/shim.go

@@ -151,12 +151,14 @@ type Shim struct {
 }
 
 type state struct {
+	Root string `json:"root"`
 	// Bundle is the path to the container's bundle
 	Bundle string `json:"bundle"`
 	// OCI runtime binary name
 	Runtime string `json:"runtime"`
 	// OCI runtime args
 	RuntimeArgs []string `json:"runtimeArgs"`
+	RuntimeRoot string   `json:"runtimeRoot"`
 	// Shim binary name
 	Name string `json:"shim"`
 	/// NoPivotRoot option
@@ -171,8 +173,10 @@ func (s *Shim) MarshalJSON() ([]byte, error) {
 		Bundle:      s.bundle,
 		Runtime:     s.runtime.Name(),
 		RuntimeArgs: s.runtime.Args(),
+		RuntimeRoot: s.runtime.Root(),
 		NoPivotRoot: s.noPivotRoot,
 		Timeout:     s.timeout,
+		Root:        s.root,
 	}
 	return json.Marshal(st)
 }
@@ -182,6 +186,7 @@ func (s *Shim) UnmarshalJSON(b []byte) error {
 	if err := json.Unmarshal(b, &st); err != nil {
 		return err
 	}
+	s.root = st.Root
 	s.name = st.Name
 	s.bundle = st.Bundle
 	s.timeout = st.Timeout
@@ -189,6 +194,7 @@ func (s *Shim) UnmarshalJSON(b []byte) error {
 	r, err := oci.New(oci.Opts{
 		Name: st.Runtime,
 		Args: st.RuntimeArgs,
+		Root: st.RuntimeRoot,
 	})
 	if err != nil {
 		return err