From 21ff3c196c250b47b71afcd36d08f8db43b5ad24 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=83=A1=E7=8E=AE=E6=96=87?= <huweiwen.hww@alibaba-inc.com>
Date: Thu, 4 Sep 2025 19:41:52 +0800
Subject: [PATCH] kubelet/metrics: fix multiple Register call

DRA also calls Register at pkg/kubelet/cm/container_manager_linux.go NewContainerManager(), causing volume stats collector being ignored.
Fix this by moving it out of `sync.Once()`, allowing multiple calls to `Register()` func.
---
 pkg/kubelet/cm/container_manager_linux.go | 2 +-
 pkg/kubelet/kubelet.go                    | 3 ++-
 pkg/kubelet/metrics/metrics.go            | 8 +++++---
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/pkg/kubelet/cm/container_manager_linux.go b/pkg/kubelet/cm/container_manager_linux.go
index c08aa56f244..c65053cd678 100644
--- a/pkg/kubelet/cm/container_manager_linux.go
+++ b/pkg/kubelet/cm/container_manager_linux.go
@@ -317,7 +317,7 @@ func NewContainerManager(mountUtil mount.Interface, cadvisorInterface cadvisor.I
 		if err != nil {
 			return nil, err
 		}
-		metrics.Register(cm.draManager.NewMetricsCollector())
+		metrics.RegisterCollectors(cm.draManager.NewMetricsCollector())
 	}
 	cm.kubeClient = kubeClient
 
diff --git a/pkg/kubelet/kubelet.go b/pkg/kubelet/kubelet.go
index d8bbe14e427..b63dd49bb0d 100644
--- a/pkg/kubelet/kubelet.go
+++ b/pkg/kubelet/kubelet.go
@@ -1632,7 +1632,8 @@ func (kl *Kubelet) StartGarbageCollection() {
 // Note that the modules here must not depend on modules that are not initialized here.
 func (kl *Kubelet) initializeModules(ctx context.Context) error {
 	// Prometheus metrics.
-	metrics.Register(
+	metrics.Register()
+	metrics.RegisterCollectors(
 		collectors.NewVolumeStatsCollector(kl),
 		collectors.NewLogMetricsCollector(kl.StatsProvider.ListPodStats),
 	)
diff --git a/pkg/kubelet/metrics/metrics.go b/pkg/kubelet/metrics/metrics.go
index 3383f6a07a3..d960989d2bd 100644
--- a/pkg/kubelet/metrics/metrics.go
+++ b/pkg/kubelet/metrics/metrics.go
@@ -1194,7 +1194,7 @@ var (
 var registerMetrics sync.Once
 
 // Register registers all metrics.
-func Register(collectors ...metrics.StableCollector) {
+func Register() {
 	// Register the metrics.
 	registerMetrics.Do(func() {
 		legacyregistry.MustRegister(FirstNetworkPodStartSLIDuration)
@@ -1274,8 +1274,6 @@ func Register(collectors ...metrics.StableCollector) {
 		legacyregistry.MustRegister(OrphanPodCleanedVolumes)
 		legacyregistry.MustRegister(OrphanPodCleanedVolumesErrors)
 
-		legacyregistry.CustomMustRegister(collectors...)
-
 		if utilfeature.DefaultFeatureGate.Enabled(features.GracefulNodeShutdown) &&
 			utilfeature.DefaultFeatureGate.Enabled(features.GracefulNodeShutdownBasedOnPodPriority) {
 			legacyregistry.MustRegister(GracefulShutdownStartTime)
@@ -1312,6 +1310,10 @@ func Register(collectors ...metrics.StableCollector) {
 	})
 }
 
+func RegisterCollectors(collectors ...metrics.StableCollector) {
+	legacyregistry.CustomMustRegister(collectors...)
+}
+
 // GetGather returns the gatherer. It used by test case outside current package.
 func GetGather() metrics.Gatherer {
 	return legacyregistry.DefaultGatherer