diff --git a/api/v1/server.go b/api/v1/server.go
index 0301ba3..2e83595 100644
--- a/api/v1/server.go
+++ b/api/v1/server.go
@@ -61,6 +61,9 @@ func (s *server) updateContainer(w http.ResponseWriter, r *http.Request) {
 	}
 	e := containerd.NewEvent(containerd.UpdateContainerEventType)
 	e.ID = id
+	if state.Signal != 0 {
+		e.Signal = syscall.Signal(state.Signal)
+	}
 	e.State = &runtime.State{
 		Status: runtime.Status(string(state.Status)),
 	}
diff --git a/api/v1/types.go b/api/v1/types.go
index d841f16..0c7acb2 100644
--- a/api/v1/types.go
+++ b/api/v1/types.go
@@ -19,6 +19,7 @@ type Machine struct {
 
 type ContainerState struct {
 	Status Status `json:"status,omitempty"`
+	Signal int    `json:"signal,omitempty"`
 }
 
 type Container struct {
diff --git a/linux/linux.go b/linux/linux.go
index a605286..c8555af 100644
--- a/linux/linux.go
+++ b/linux/linux.go
@@ -225,7 +225,14 @@ func (c *libcontainerContainer) getCheckpointPath(name string) string {
 
 func (c *libcontainerContainer) Checkpoint(cp runtime.Checkpoint) error {
 	opts := c.createCheckpointOpts(cp)
-	if err := os.MkdirAll(opts.ImagesDirectory, 0755); err != nil {
+	if err := os.MkdirAll(filepath.Dir(opts.ImagesDirectory), 0755); err != nil {
+		return err
+	}
+	// mkdir is atomic so if it already exists we can fail
+	if err := os.Mkdir(opts.ImagesDirectory, 0755); err != nil {
+		if os.IsExist(err) {
+			return runtime.ErrCheckpointExists
+		}
 		return err
 	}
 	if err := c.c.Checkpoint(opts); err != nil {
diff --git a/runtime/runtime.go b/runtime/runtime.go
index 230239d..b92861a 100644
--- a/runtime/runtime.go
+++ b/runtime/runtime.go
@@ -10,6 +10,7 @@ var (
 	ErrNotChildProcess      = errors.New("containerd: not a child process for container")
 	ErrInvalidContainerType = errors.New("containerd: invalid container type for runtime")
 	ErrCheckpointNotExists  = errors.New("containerd: checkpoint does not exist for container")
+	ErrCheckpointExists     = errors.New("containerd: checkpoint already exists")
 )
 
 // runtime handles containers, containers handle their own actions.
diff --git a/update.go b/update.go
index ea121ee..f27cbc3 100644
--- a/update.go
+++ b/update.go
@@ -25,5 +25,16 @@ func (h *UpdateEvent) Handle(e *Event) error {
 			return ErrUnknownContainerStatus
 		}
 	}
+	if e.Signal != nil {
+		// signal the pid1/main process of the container
+		processes, err := container.Processes()
+		if err != nil {
+			return err
+		}
+		if len(processes) == 0 {
+			return ErrProcessNotFound
+		}
+		return processes[0].Signal(e.Signal)
+	}
 	return nil
 }