Fix a bug for standalone where it appears that DEPLOY_MODE is get/used before set. (#15712)

Signed-off-by: Yuchen Gao <yuchen.gao@zilliz.com>

cmd/roles/roles.go

@@ -70,7 +70,7 @@ func stopRocksmq() {
 	rocksmq.CloseRocksMQ()
 }
 
-// MilvusRoles determines to run which components.
+// MilvusRoles decides which components are brought up with Milvus.
 type MilvusRoles struct {
 	EnableRootCoord  bool `env:"ENABLE_ROOT_COORD"`
 	EnableProxy      bool `env:"ENABLE_PROXY"`
@@ -343,21 +343,14 @@ func (mr *MilvusRoles) runIndexNode(ctx context.Context, localMsg bool, alias st
 
 // Run Milvus components.
 func (mr *MilvusRoles) Run(local bool, alias string) {
-	if os.Getenv(metricsinfo.DeployModeEnvKey) == metricsinfo.StandaloneDeployMode {
-		closer := trace.InitTracing("standalone")
-		if closer != nil {
-			defer closer.Close()
-		}
-	}
-
 	ctx, cancel := context.WithCancel(context.Background())
 
 	// only standalone enable localMsg
 	if local {
-		Params.Init()
 		if err := os.Setenv(metricsinfo.DeployModeEnvKey, metricsinfo.StandaloneDeployMode); err != nil {
 			log.Error("Failed to set deploy mode: ", zap.Error(err))
 		}
+		Params.Init()
 
 		if err := initRocksmq(); err != nil {
 			panic(err)
@@ -365,7 +358,7 @@ func (mr *MilvusRoles) Run(local bool, alias string) {
 		defer stopRocksmq()
 
 		if Params.EtcdCfg.UseEmbedEtcd {
-			// start etcd server
+			// Start etcd server.
 			etcd.InitEtcdServer(&Params.EtcdCfg)
 			defer etcd.StopEtcdServer()
 		}
@@ -375,6 +368,13 @@ func (mr *MilvusRoles) Run(local bool, alias string) {
 		}
 	}
 
+	if os.Getenv(metricsinfo.DeployModeEnvKey) == metricsinfo.StandaloneDeployMode {
+		closer := trace.InitTracing("standalone")
+		if closer != nil {
+			defer closer.Close()
+		}
+	}
+
 	var rc *components.RootCoord
 	if mr.EnableRootCoord {
 		rc = mr.runRootCoord(ctx, local)