Add logging and monitoring in case we have minimum memory recommendat…

…ions

vertical-pod-autoscaler/pkg/recommender/logic/estimator.go

@@ -17,10 +17,15 @@ limitations under the License.
 package logic
 
 import (
+	"encoding/json"
 	"math"
 	"time"
 
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/klog/v2"
+
 	"k8s.io/autoscaler/vertical-pod-autoscaler/pkg/recommender/model"
+	metrics_quality "k8s.io/autoscaler/vertical-pod-autoscaler/pkg/utils/metrics/quality"
 )
 
 // TODO: Split the estimator to have a separate estimator object for CPU and memory.
@@ -53,6 +58,7 @@ type marginEstimator struct {
 type minResourcesEstimator struct {
 	minResources  model.Resources
 	baseEstimator ResourceEstimator
+	vpaKey        model.VpaID
 }
 
 type confidenceMultiplier struct {
@@ -79,8 +85,8 @@ func WithMargin(marginFraction float64, baseEstimator ResourceEstimator) Resourc
 
 // WithMinResources returns a given ResourceEstimator with minResources applied.
 // The returned resources are equal to the max(original resources, minResources)
-func WithMinResources(minResources model.Resources, baseEstimator ResourceEstimator) ResourceEstimator {
-	return &minResourcesEstimator{minResources, baseEstimator}
+func WithMinResources(minResources model.Resources, baseEstimator ResourceEstimator, vpaKey model.VpaID) ResourceEstimator {
+	return &minResourcesEstimator{minResources, baseEstimator, vpaKey}
 }
 
 // WithConfidenceMultiplier returns a given ResourceEstimator with confidenceMultiplier applied.
@@ -152,9 +158,31 @@ func (e *minResourcesEstimator) GetResourceEstimation(s *model.AggregateContaine
 	newResources := make(model.Resources)
 	for resource, resourceAmount := range originalResources {
 		if resourceAmount < e.minResources[resource] {
+			if resource == "memory" {
+				klog.Warningf("Computed resources for %s were below minimum! Computed %v, minimum is %v.", resource, resourceAmount, e.minResources[resource])
+				logHistogramInformation(s)
+				metrics_quality.ObserveLowerThanMinRecommendation(s.GetUpdateMode(), corev1.ResourceName(resource), e.vpaKey.Namespace+"/"+e.vpaKey.VpaName)
+			}
 			resourceAmount = e.minResources[resource]
 		}
 		newResources[resource] = resourceAmount
 	}
 	return newResources
 }
+
+func logHistogramInformation(s *model.AggregateContainerState) {
+	if s.AggregateCPUUsage == nil {
+		klog.Warning("Aggregate CPU usage has no metric samples, cannot show internal histogram data!")
+		return
+	}
+	if s.AggregateMemoryPeaks == nil {
+		klog.Warning("Aggregate memory usage has no metric samples, cannot show internal histogram data!")
+		return
+	}
+	c, _ := s.SaveToCheckpoint()
+	prettyCheckpoint, err := json.MarshalIndent(c, "", "  ")
+	if err != nil {
+		klog.Errorf("Error during marshalling checkpoint: %s", err)
+	}
+	klog.Warningf("Here's the checkpoint/state: %s", prettyCheckpoint)
+}

vertical-pod-autoscaler/pkg/recommender/logic/recommender.go

@@ -38,7 +38,7 @@ var (
 
 // PodResourceRecommender computes resource recommendation for a Vpa object.
 type PodResourceRecommender interface {
-	GetRecommendedPodResources(containerNameToAggregateStateMap model.ContainerNameToAggregateStateMap) RecommendedPodResources
+	GetRecommendedPodResources(containerNameToAggregateStateMap model.ContainerNameToAggregateStateMap, vpaKey model.VpaID) RecommendedPodResources
 }
 
 // RecommendedPodResources is a Map from container name to recommended resources.
@@ -61,7 +61,7 @@ type podResourceRecommender struct {
 	upperBoundEstimator ResourceEstimator
 }
 
-func (r *podResourceRecommender) GetRecommendedPodResources(containerNameToAggregateStateMap model.ContainerNameToAggregateStateMap) RecommendedPodResources {
+func (r *podResourceRecommender) GetRecommendedPodResources(containerNameToAggregateStateMap model.ContainerNameToAggregateStateMap, vpaKey model.VpaID) RecommendedPodResources {
 	var recommendation = make(RecommendedPodResources)
 	if len(containerNameToAggregateStateMap) == 0 {
 		return recommendation
@@ -74,9 +74,9 @@ func (r *podResourceRecommender) GetRecommendedPodResources(containerNameToAggre
 	}
 
 	recommender := &podResourceRecommender{
-		WithMinResources(minResources, r.targetEstimator),
-		WithMinResources(minResources, r.lowerBoundEstimator),
-		WithMinResources(minResources, r.upperBoundEstimator),
+		WithMinResources(minResources, r.targetEstimator, vpaKey),
+		WithMinResources(minResources, r.lowerBoundEstimator, vpaKey),
+		WithMinResources(minResources, r.upperBoundEstimator, vpaKey),
 	}
 
 	for containerName, aggregatedContainerState := range containerNameToAggregateStateMap {

vertical-pod-autoscaler/pkg/recommender/logic/recommender_test.go

@@ -17,9 +17,10 @@ limitations under the License.
 package logic
 
 import (
+	"testing"
+
 	"github.com/stretchr/testify/assert"
 	"k8s.io/autoscaler/vertical-pod-autoscaler/pkg/recommender/model"
-	"testing"
 )
 
 func TestMinResourcesApplied(t *testing.T) {
@@ -36,7 +37,7 @@ func TestMinResourcesApplied(t *testing.T) {
 		"container-1": &model.AggregateContainerState{},
 	}
 
-	recommendedResources := recommender.GetRecommendedPodResources(containerNameToAggregateStateMap)
+	recommendedResources := recommender.GetRecommendedPodResources(containerNameToAggregateStateMap, nil)
 	assert.Equal(t, model.CPUAmountFromCores(*podMinCPUMillicores/1000), recommendedResources["container-1"].Target[model.ResourceCPU])
 	assert.Equal(t, model.MemoryAmountFromBytes(*podMinMemoryMb*1024*1024), recommendedResources["container-1"].Target[model.ResourceMemory])
 }
@@ -56,7 +57,7 @@ func TestMinResourcesSplitAcrossContainers(t *testing.T) {
 		"container-2": &model.AggregateContainerState{},
 	}
 
-	recommendedResources := recommender.GetRecommendedPodResources(containerNameToAggregateStateMap)
+	recommendedResources := recommender.GetRecommendedPodResources(containerNameToAggregateStateMap, nil)
 	assert.Equal(t, model.CPUAmountFromCores((*podMinCPUMillicores/1000)/2), recommendedResources["container-1"].Target[model.ResourceCPU])
 	assert.Equal(t, model.CPUAmountFromCores((*podMinCPUMillicores/1000)/2), recommendedResources["container-2"].Target[model.ResourceCPU])
 	assert.Equal(t, model.MemoryAmountFromBytes((*podMinMemoryMb*1024*1024)/2), recommendedResources["container-1"].Target[model.ResourceMemory])
@@ -80,7 +81,7 @@ func TestControlledResourcesFiltered(t *testing.T) {
 		},
 	}
 
-	recommendedResources := recommender.GetRecommendedPodResources(containerNameToAggregateStateMap)
+	recommendedResources := recommender.GetRecommendedPodResources(containerNameToAggregateStateMap, nil)
 	assert.Contains(t, recommendedResources[containerName].Target, model.ResourceMemory)
 	assert.Contains(t, recommendedResources[containerName].LowerBound, model.ResourceMemory)
 	assert.Contains(t, recommendedResources[containerName].UpperBound, model.ResourceMemory)
@@ -106,7 +107,7 @@ func TestControlledResourcesFilteredDefault(t *testing.T) {
 		},
 	}
 
-	recommendedResources := recommender.GetRecommendedPodResources(containerNameToAggregateStateMap)
+	recommendedResources := recommender.GetRecommendedPodResources(containerNameToAggregateStateMap, nil)
 	assert.Contains(t, recommendedResources[containerName].Target, model.ResourceMemory)
 	assert.Contains(t, recommendedResources[containerName].LowerBound, model.ResourceMemory)
 	assert.Contains(t, recommendedResources[containerName].UpperBound, model.ResourceMemory)

vertical-pod-autoscaler/pkg/recommender/routines/recommender.go

@@ -91,7 +91,7 @@ func (r *recommender) UpdateVPAs() {
 		if !found {
 			continue
 		}
-		resources := r.podResourceRecommender.GetRecommendedPodResources(GetContainerNameToAggregateStateMap(vpa))
+		resources := r.podResourceRecommender.GetRecommendedPodResources(GetContainerNameToAggregateStateMap(vpa), key)
 		had := vpa.HasRecommendation()
 
 		listOfResourceRecommendation := logic.MapToListOfRecommendedContainerResources(resources)

vertical-pod-autoscaler/pkg/utils/metrics/quality/quality.go

@@ -116,6 +116,13 @@ var (
 			Buckets:   relativeBuckets,
 		}, []string{"update_mode", "resource", "vpa_size_log2"},
 	)
+	lowerThanMinRecommendationCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: metricsNamespace,
+			Name:      "lower_than_min_recommendation_count",
+			Help:      "Count of usage samples when resource recommendation values are lower than the minimum",
+		}, []string{"update_mode", "resource", "vpa"},
+	)
 )
 
 // Register initializes all VPA quality metrics
@@ -129,6 +136,7 @@ func Register() {
 	prometheus.MustRegister(cpuRecommendations)
 	prometheus.MustRegister(memoryRecommendations)
 	prometheus.MustRegister(relativeRecommendationChange)
+	prometheus.MustRegister(lowerThanMinRecommendationCounter)
 }
 
 // observeUsageRecommendationRelativeDiff records relative diff between usage and
@@ -222,6 +230,11 @@ func ObserveRecommendationChange(previous, current corev1.ResourceList, updateMo
 	}
 }
 
+// ObserveLowerThanMinRecommendation counts usage samples with lower than min memory recommendations.
+func ObserveLowerThanMinRecommendation(updateMode *vpa_types.UpdateMode, resource corev1.ResourceName, vpaKey string) {
+	lowerThanMinRecommendationCounter.WithLabelValues(updateModeToString(updateMode), string(resource), vpaKey).Inc()
+}
+
 // quantityAsFloat converts resource.Quantity to a float64 value, in some scale (constant per resource but unspecified)
 func quantityAsFloat(resource corev1.ResourceName, quantity resource.Quantity) float64 {
 	switch resource {