Add support for sd_notify for start / stop

dockershim/remote/docker_server.go

@@ -91,5 +91,6 @@ func (s *DockerServer) Start() error {
 			os.Exit(1)
 		}
 	}()
+	handleNotify()
 	return nil
 }

dockershim/remote/docker_server_unix.go

@@ -4,8 +4,12 @@ package remote
 
 import (
 	"net"
+	"os"
+	"os/signal"
+	"syscall"
 
 	"github.com/coreos/go-systemd/v22/activation"
+	"github.com/coreos/go-systemd/v22/daemon"
 	"github.com/pkg/errors"
 )
 
@@ -32,3 +36,22 @@ func listenFD(addr string) (net.Listener, error) {
 	//TODO: systemd fd selection (default is 3)
 	return nil, errors.New("not supported yet")
 }
+
+func sdNotify(state string) error {
+	_, err := daemon.SdNotify(false, state)
+	if err != nil {
+		//TODO: log the notification error
+		return err
+	}
+	return nil
+}
+
+func handleNotify() {
+	sdNotify(daemon.SdNotifyReady)
+	sigs := make(chan os.Signal, 1)
+	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+	go func() {
+		<-sigs
+		sdNotify(daemon.SdNotifyStopping)
+	}()
+}

dockershim/remote/docker_server_windows.go

@@ -11,3 +11,6 @@ import (
 func listenFD(addr string) (net.Listener, error) {
 	return nil, errors.New("listening server on fd not supported on windows")
 }
+
+func handleNotify() {
+}

packaging/systemd/cri-docker.service

@@ -8,7 +8,7 @@ Requires=cri-docker.socket
 
 [Service]
 Type=notify
-ExecStart=/usr/bin/cri-dockerd --container-runtime-endpoint fd:// --network-plugin=""
+ExecStart=/usr/bin/cri-dockerd --container-runtime-endpoint fd:// --network-plugin=
 ExecReload=/bin/kill -s HUP $MAINPID
 TimeoutSec=0
 RestartSec=2