fail ready/liveness if etcd is unhealthy in gateway mode (#13146)

cmd/gateway-main.go

@@ -301,9 +301,6 @@ func StartGateway(ctx *cli.Context, gw Gateway) {
 		logger.FatalIf(globalNotificationSys.Init(GlobalContext, buckets, newObject), "Unable to initialize notification system")
 	}
 
-	// Initialize users credentials and policies in background.
-	globalIAMSys.InitStore(newObject)
-
 	go globalIAMSys.Init(GlobalContext, newObject)
 
 	if globalCacheConfig.Enabled {

cmd/healthcheck-handler.go

@@ -95,6 +95,17 @@ func ReadinessCheckHandler(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set(xhttp.MinIOServerStatus, unavailable)
 	}
 
+	if globalIsGateway && globalEtcdClient != nil {
+		// Borrowed from https://github.com/etcd-io/etcd/blob/main/etcdctl/ctlv3/command/ep_command.go#L118
+		ctx, cancel := context.WithTimeout(r.Context(), defaultContextTimeout)
+		defer cancel()
+		// etcd unreachable throw an error for readiness.
+		if _, err := globalEtcdClient.Get(ctx, "health"); err != nil {
+			writeErrorResponse(r.Context(), w, toAPIError(r.Context(), err), r.URL)
+			return
+		}
+	}
+
 	writeResponse(w, http.StatusOK, nil, mimeNone)
 }
 
@@ -104,5 +115,17 @@ func LivenessCheckHandler(w http.ResponseWriter, r *http.Request) {
 		// Service not initialized yet
 		w.Header().Set(xhttp.MinIOServerStatus, unavailable)
 	}
+
+	if globalIsGateway && globalEtcdClient != nil {
+		// Borrowed from https://github.com/etcd-io/etcd/blob/main/etcdctl/ctlv3/command/ep_command.go#L118
+		ctx, cancel := context.WithTimeout(r.Context(), defaultContextTimeout)
+		defer cancel()
+		// etcd unreachable throw an error for readiness.
+		if _, err := globalEtcdClient.Get(ctx, "health"); err != nil {
+			writeErrorResponse(r.Context(), w, toAPIError(r.Context(), err), r.URL)
+			return
+		}
+	}
+
 	writeResponse(w, http.StatusOK, nil, mimeNone)
 }