Add readiness and liveness probes in controller (#6570)

Co-authored-by: Lionel Villard <villard@us.ibm.com>

cmd/controller/main.go

@@ -20,6 +20,10 @@ import (
 	// Uncomment the following line to load the gcp plugin (only required to authenticate against GKE clusters).
 	// _ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
 
+	"log"
+	"net/http"
+	"os"
+
 	"knative.dev/pkg/injection/sharedmain"
 
 	"knative.dev/eventing/pkg/reconciler/apiserversource"
@@ -36,6 +40,24 @@ import (
 )
 
 func main() {
+	// sets up liveness and readiness probes.
+	mux := http.NewServeMux()
+
+	mux.HandleFunc("/", handler)
+	mux.HandleFunc("/health", handler)
+	mux.HandleFunc("/readiness", handler)
+
+	port := os.Getenv("PROBES_PORT")
+	if port == "" {
+		port = "8080"
+	}
+
+	go func() {
+		// start the web server on port and accept requests
+		log.Printf("Readiness and health check server listening on port %s", port)
+		log.Fatal(http.ListenAndServe(":"+port, mux))
+	}()
+
 	sharedmain.Main("controller",
 		// Messaging
 		channel.NewController,
@@ -60,3 +82,7 @@ func main() {
 		sugartrigger.NewController,
 	)
 }
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(http.StatusOK)
+}

config/core/deployments/controller.yaml

@@ -98,8 +98,27 @@ spec:
             drop:
             - all
 
+        livenessProbe:
+          httpGet:
+            path: /health
+            port: probes
+            scheme: HTTP
+          initialDelaySeconds: 20
+          periodSeconds: 10
+          timeoutSeconds: 5
+        readinessProbe:
+          httpGet:
+            path: /readiness
+            port: probes
+            scheme: HTTP
+          initialDelaySeconds: 20
+          periodSeconds: 10
+          timeoutSeconds: 5
+
         ports:
         - name: metrics
           containerPort: 9090
         - name: profiling
           containerPort: 8008
+        - name: probes
+          containerPort: 8080