feat: Add /livez for Liveness Probes (#45454) (#45481)

issue: https://github.com/milvus-io/milvus/issues/45443
pr: https://github.com/milvus-io/milvus/pull/45454

Signed-off-by: zhenshan.cao <zhenshan.cao@zilliz.com>

internal/http/healthz/livez_handler.go

@@ -0,0 +1,39 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package healthz
+
+import (
+	"fmt"
+	"net/http"
+)
+
+// LivenessHandler returns the HTTP Handler for the LIGHTWEIGHT liveness check (/livez).
+// This is designed to be the target for the Kubernetes Liveness Probe.
+func LivenessHandler() http.Handler {
+	return http.HandlerFunc(LivezHandlerFunc)
+}
+
+// LivezHandlerFunc executes the minimal, non-blocking check for process activity.
+// It confirms the Go scheduler is active and the HTTP server can respond immediately.
+func LivezHandlerFunc(w http.ResponseWriter, r *http.Request) {
+	// IMPORTANT: This check must be non-blocking. No external calls (Etcd, MinIO)
+	// or checks against other internal Milvus component states are allowed here.
+
+	w.WriteHeader(http.StatusOK)
+	// Return a simple string to confirm scheduler activity.
+	fmt.Fprintln(w, "Milvus Process Active")
+}

internal/http/router.go

@@ -19,6 +19,9 @@ package http
 // HealthzRouterPath is default path for check health state.
 const HealthzRouterPath = "/healthz"
 
+// LivezRouterPath is the lightweight path dedicated to checking process liveness.
+const LivezRouterPath = "/livez"
+
 // LogLevelRouterPath is path for Get and Update log level at runtime.
 const LogLevelRouterPath = "/log/level"
 

internal/http/server.go

@@ -76,6 +76,10 @@ func registerDefaults() {
 		Path:    HealthzRouterPath,
 		Handler: healthz.Handler(),
 	})
+	Register(&Handler{
+		Path:    LivezRouterPath,
+		Handler: healthz.LivenessHandler(),
+	})
 	Register(&Handler{
 		Path:    EventLogRouterPath,
 		Handler: eventlog.Handler(),