Merge pull request #99095 from maxlaverse/fix_kubelet_stuck_in_diskpressure

Prevent Kubelet from getting stuck in DiskPressure when imagefs minReclaim is set

pkg/kubelet/eviction/eviction_manager.go

@@ -437,8 +437,9 @@ func (m *managerImpl) reclaimNodeLevelResources(signalToReclaim evictionapi.Sign
 		observations, _ := makeSignalObservations(summary)
 		debugLogObservations("observations after resource reclaim", observations)
 
-		// determine the set of thresholds met independent of grace period
-		thresholds := thresholdsMet(m.config.Thresholds, observations, false)
+		// evaluate all thresholds independently of their grace period to see if with
+		// the new observations, we think we have met min reclaim goals
+		thresholds := thresholdsMet(m.config.Thresholds, observations, true)
 		debugLogThresholdsWithObservation("thresholds after resource reclaim - ignoring grace period", thresholds, observations)
 
 		if len(thresholds) == 0 {

pkg/kubelet/eviction/eviction_manager_test.go

@@ -886,6 +886,51 @@ func TestNodeReclaimFuncs(t *testing.T) {
 		t.Errorf("Manager should not report disk pressure")
 	}
 
+	// synchronize
+	manager.synchronize(diskInfoProvider, activePodsFunc)
+
+	// we should not have disk pressure
+	if manager.IsUnderDiskPressure() {
+		t.Errorf("Manager should not report disk pressure")
+	}
+
+	// induce hard threshold
+	fakeClock.Step(1 * time.Minute)
+	summaryProvider.result = summaryStatsMaker(".9Gi", "200Gi", podStats)
+	// make GC return disk usage bellow the threshold, but not satisfying minReclaim
+	diskGC.summaryAfterGC = summaryStatsMaker("1.1Gi", "200Gi", podStats)
+	manager.synchronize(diskInfoProvider, activePodsFunc)
+
+	// we should have disk pressure
+	if !manager.IsUnderDiskPressure() {
+		t.Errorf("Manager should report disk pressure since soft threshold was met")
+	}
+
+	// verify image gc was invoked
+	if !diskGC.imageGCInvoked || !diskGC.containerGCInvoked {
+		t.Errorf("Manager should have invoked image gc")
+	}
+
+	// verify a pod was killed because image gc was not enough to satisfy minReclaim
+	if podKiller.pod == nil {
+		t.Errorf("Manager should have killed a pod, but didn't")
+	}
+
+	// reset state
+	diskGC.imageGCInvoked = false
+	diskGC.containerGCInvoked = false
+	podKiller.pod = nil
+
+	// remove disk pressure
+	fakeClock.Step(20 * time.Minute)
+	summaryProvider.result = summaryStatsMaker("16Gi", "200Gi", podStats)
+	manager.synchronize(diskInfoProvider, activePodsFunc)
+
+	// we should not have disk pressure
+	if manager.IsUnderDiskPressure() {
+		t.Errorf("Manager should not report disk pressure")
+	}
+
 	// induce disk pressure!
 	fakeClock.Step(1 * time.Minute)
 	summaryProvider.result = summaryStatsMaker("400Mi", "200Gi", podStats)