From 500bfe00cdbec423ebb23467d3d49967d4f8ea8f Mon Sep 17 00:00:00 2001
From: Keisuke Ishigami <k.130.email@gmail.com>
Date: Thu, 10 Jul 2025 02:59:21 +0900
Subject: [PATCH] Prevent the failure of releasing the lock by updating the
 resource version in case of a resource conflict

Kubernetes-commit: 271233a62aeab02eb0f7a6567d3ddba6d09a4f21
---
 tools/leaderelection/leaderelection.go | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/tools/leaderelection/leaderelection.go b/tools/leaderelection/leaderelection.go
index c3c1d9be..35afc372 100644
--- a/tools/leaderelection/leaderelection.go
+++ b/tools/leaderelection/leaderelection.go
@@ -306,17 +306,37 @@ func (le *LeaderElector) renew(ctx context.Context) {
 
 // release attempts to release the leader lease if we have acquired it.
 func (le *LeaderElector) release() bool {
+	ctx := context.Background()
+
+	// 1. obtain the electionRecord
+	oldLeaderElectionRecord, oldLeaderElectionRawRecord, err := le.config.Lock.Get(ctx)
+	if err != nil {
+		if !errors.IsNotFound(err) {
+			klog.Errorf("error retrieving resource lock %v: %v", le.config.Lock.Describe(), err)
+			return false
+		}
+		klog.Infof("lease lock not found: %v", le.config.Lock.Describe())
+		return false
+	}
+	// 2. Record obtained, check the Identity & Time
+	if !bytes.Equal(le.observedRawRecord, oldLeaderElectionRawRecord) {
+		le.setObservedRecord(oldLeaderElectionRecord)
+
+		le.observedRawRecord = oldLeaderElectionRawRecord
+	}
+
 	if !le.IsLeader() {
 		return true
 	}
 	now := metav1.NewTime(le.clock.Now())
 	leaderElectionRecord := rl.LeaderElectionRecord{
-		LeaderTransitions:    le.observedRecord.LeaderTransitions,
+		LeaderTransitions:    oldLeaderElectionRecord.LeaderTransitions,
 		LeaseDurationSeconds: 1,
 		RenewTime:            now,
 		AcquireTime:          now,
 	}
-	timeoutCtx, timeoutCancel := context.WithTimeout(context.Background(), le.config.RenewDeadline)
+
+	timeoutCtx, timeoutCancel := context.WithTimeout(ctx, le.config.RenewDeadline)
 	defer timeoutCancel()
 	if err := le.config.Lock.Update(timeoutCtx, leaderElectionRecord); err != nil {
 		klog.Errorf("Failed to release lock: %v", err)