Add support for sd_notify

Signed-off-by: Dan Walsh <dwalsh@redhat.com>

cmd/server/daemon_linux.go

@@ -0,0 +1,20 @@
+// +build linux
+
+package main
+
+import (
+	"github.com/Sirupsen/logrus"
+	systemdDaemon "github.com/coreos/go-systemd/daemon"
+)
+
+func sdNotify() {
+	if err := systemdDaemon.SdNotify("READY=1"); err != nil {
+		logrus.Warnf("Failed to sd_notify systemd: %v", err)
+	}
+}
+
+// notifySystem sends a message to the host when the server is ready to be used
+func notifySystem() {
+	// Tell the init daemon we are accepting requests
+	go sdNotify()
+}

cmd/server/main.go

@@ -188,6 +188,10 @@ func main() {
 
 		runtime.RegisterRuntimeServiceServer(s, service)
 		runtime.RegisterImageServiceServer(s, service)
+
+		// after the daemon is done setting up we can notify systemd api
+		notifySystem()
+
 		if err := s.Serve(lis); err != nil {
 			logrus.Fatal(err)
 		}