Merge pull request #777 from arschles/probes

Add HTTP server for liveness and readiness probes

cmd/tiller/probes.go

+package main
+
+import (
+	"net/http"
+)
+
+func readinessProbe(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(http.StatusOK)
+}
+
+func livenessProbe(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(http.StatusOK)
+}
+
+func newProbesMux() *http.ServeMux {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/readiness", readinessProbe)
+	mux.HandleFunc("/liveness", livenessProbe)
+	return mux
+}

cmd/tiller/probes_test.go

+package main
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestProbesServer(t *testing.T) {
+	mux := newProbesMux()
+	srv := httptest.NewServer(mux)
+	defer srv.Close()
+	resp, err := http.Get(srv.URL + "/readiness")
+	if err != nil {
+		t.Fatalf("GET /readiness returned an error (%s)", err)
+	}
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("GET /readiness returned status code %d, expected %d", resp.StatusCode, http.StatusOK)
+	}
+
+	resp, err = http.Get(srv.URL + "/liveness")
+	if err != nil {
+		t.Fatalf("GET /liveness returned an error (%s)", err)
+	}
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("GET /liveness returned status code %d, expected %d", resp.StatusCode, http.StatusOK)
+	}
+}

cmd/tiller/tiller.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"net"
+	"net/http"
 	"os"
 
 	"github.com/kubernetes/helm/cmd/tiller/environment"
@@ -21,6 +22,7 @@ var rootServer = grpc.NewServer()
 var env = environment.New()
 
 var addr = ":44134"
+var probe = ":44135"
 var namespace = ""
 
 const globalUsage = `The Kubernetes Helm server.
@@ -53,10 +55,29 @@ func start(c *cobra.Command, args []string) {
 	}
 
 	fmt.Printf("Tiller is running on %s\n", addr)
+	fmt.Printf("Tiller probes server is running on %s\n", probe)
 
-	if err := rootServer.Serve(lstn); err != nil {
+	srvErrCh := make(chan error)
+	probeErrCh := make(chan error)
+	go func() {
+		if err := rootServer.Serve(lstn); err != nil {
+			srvErrCh <- err
+		}
+	}()
+
+	go func() {
+		mux := newProbesMux()
+		if err := http.ListenAndServe(addr, mux); err != nil {
+			probeErrCh <- err
+		}
+	}()
+
+	select {
+	case err := <-srvErrCh:
 		fmt.Fprintf(os.Stderr, "Server died: %s\n", err)
 		os.Exit(1)
+	case err := <-probeErrCh:
+		fmt.Fprintf(os.Stderr, "Probes server died: %s\n", err)
 	}
 }
 

pkg/client/install.go

@@ -108,4 +108,16 @@ spec:
         - containerPort: 44134
           name: tiller
         imagePullPolicy: Always
+        livenessProbe:
+          httpGet:
+            path: /liveness
+            port: 44135
+          initialDelaySeconds: 1
+          timeoutSeconds: 1
+        readinessProbe:
+          httpGet:
+            path: /readiness
+            port: 44135
+          initialDelaySeconds: 1
+          timeoutSeconds: 1
 `