Refactor kubelet metricsets to share response from endpoint (#25782)

(cherry picked from commit a39dd00)

CHANGELOG.next.asciidoc

@@ -616,6 +616,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Refactor state_* metricsets to share response from endpoint. {pull}25640[25640]
 - Add server id to zookeeper events. {pull}25550[25550]
 - Add additional network metrics to docker/network {pull}25354[25354]
+- Reduce number of requests done by kubernetes metricsets to kubelet. {pull}25782[25782]
 
 *Packetbeat*
 

metricbeat/module/kubernetes/container/container.go

@@ -18,12 +18,15 @@
 package container
 
 import (
+	"fmt"
+
 	"github.com/pkg/errors"
 
 	"github.com/elastic/beats/v7/libbeat/logp"
 	"github.com/elastic/beats/v7/metricbeat/helper"
 	"github.com/elastic/beats/v7/metricbeat/mb"
 	"github.com/elastic/beats/v7/metricbeat/mb/parse"
+	k8smod "github.com/elastic/beats/v7/metricbeat/module/kubernetes"
 	"github.com/elastic/beats/v7/metricbeat/module/kubernetes/util"
 )
 
@@ -58,6 +61,7 @@ type MetricSet struct {
 	mb.BaseMetricSet
 	http     *helper.HTTP
 	enricher util.Enricher
+	mod      k8smod.Module
 }
 
 // New create a new instance of the MetricSet
@@ -68,10 +72,15 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 	if err != nil {
 		return nil, err
 	}
+	mod, ok := base.Module().(k8smod.Module)
+	if !ok {
+		return nil, fmt.Errorf("must be child of kubernetes module")
+	}
 	return &MetricSet{
 		BaseMetricSet: base,
 		http:          http,
 		enricher:      util.NewContainerMetadataEnricher(base, true),
+		mod:           mod,
 	}, nil
 }
 
@@ -81,7 +90,7 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *MetricSet) Fetch(reporter mb.ReporterV2) error {
 	m.enricher.Start()
 
-	body, err := m.http.FetchContent()
+	body, err := m.mod.GetKubeletStats(m.http)
 	if err != nil {
 		return errors.Wrap(err, "error doing HTTP request to fetch 'container' Metricset data")
 

metricbeat/module/kubernetes/kubernetes.go

@@ -25,6 +25,7 @@ import (
 	"github.com/pkg/errors"
 	dto "github.com/prometheus/client_model/go"
 
+	"github.com/elastic/beats/v7/metricbeat/helper"
 	p "github.com/elastic/beats/v7/metricbeat/helper/prometheus"
 	"github.com/elastic/beats/v7/metricbeat/mb"
 )
@@ -38,7 +39,8 @@ func init() {
 
 type Module interface {
 	mb.Module
-	GetSharedFamilies(prometheus p.Prometheus) ([]*dto.MetricFamily, error)
+	GetStateMetricsFamilies(prometheus p.Prometheus) ([]*dto.MetricFamily, error)
+	GetKubeletStats(http *helper.HTTP) ([]byte, error)
 }
 
 type familiesCache struct {
@@ -53,55 +55,95 @@ type kubeStateMetricsCache struct {
 }
 
 func (c *kubeStateMetricsCache) getCacheMapEntry(hash uint64) *familiesCache {
-	c.lock.Lock()
-	defer c.lock.Unlock()
 	if _, ok := c.cacheMap[hash]; !ok {
 		c.cacheMap[hash] = &familiesCache{}
 	}
 	return c.cacheMap[hash]
 }
 
+type statsCache struct {
+	sharedStats        []byte
+	lastFetchErr       error
+	lastFetchTimestamp time.Time
+}
+
+type kubeletStatsCache struct {
+	cacheMap map[uint64]*statsCache
+	lock     sync.Mutex
+}
+
+func (c *kubeletStatsCache) getCacheMapEntry(hash uint64) *statsCache {
+	if _, ok := c.cacheMap[hash]; !ok {
+		c.cacheMap[hash] = &statsCache{}
+	}
+	return c.cacheMap[hash]
+}
+
 type module struct {
 	mb.BaseModule
 
 	kubeStateMetricsCache *kubeStateMetricsCache
-	familiesCache         *familiesCache
+	kubeletStatsCache     *kubeletStatsCache
+	cacheHash             uint64
 }
 
 func ModuleBuilder() func(base mb.BaseModule) (mb.Module, error) {
 	kubeStateMetricsCache := &kubeStateMetricsCache{
 		cacheMap: make(map[uint64]*familiesCache),
 	}
+	kubeletStatsCache := &kubeletStatsCache{
+		cacheMap: make(map[uint64]*statsCache),
+	}
 	return func(base mb.BaseModule) (mb.Module, error) {
 		hash, err := generateCacheHash(base.Config().Hosts)
 		if err != nil {
 			return nil, errors.Wrap(err, "error generating cache hash for kubeStateMetricsCache")
 		}
-		// NOTE: These entries will be never removed, this can be a leak if
-		// metricbeat is used to monitor clusters dynamically created.
-		// (https://github.com/elastic/beats/pull/25640#discussion_r633395213)
-		familiesCache := kubeStateMetricsCache.getCacheMapEntry(hash)
 		m := module{
 			BaseModule:            base,
 			kubeStateMetricsCache: kubeStateMetricsCache,
-			familiesCache:         familiesCache,
+			kubeletStatsCache:     kubeletStatsCache,
+			cacheHash:             hash,
 		}
 		return &m, nil
 	}
 }
 
-func (m *module) GetSharedFamilies(prometheus p.Prometheus) ([]*dto.MetricFamily, error) {
+func (m *module) GetStateMetricsFamilies(prometheus p.Prometheus) ([]*dto.MetricFamily, error) {
 	m.kubeStateMetricsCache.lock.Lock()
 	defer m.kubeStateMetricsCache.lock.Unlock()
 
 	now := time.Now()
+	// NOTE: These entries will be never removed, this can be a leak if
+	// metricbeat is used to monitor clusters dynamically created.
+	// (https://github.com/elastic/beats/pull/25640#discussion_r633395213)
+	familiesCache := m.kubeStateMetricsCache.getCacheMapEntry(m.cacheHash)
+
+	if familiesCache.lastFetchTimestamp.IsZero() || now.Sub(familiesCache.lastFetchTimestamp) > m.Config().Period {
+		familiesCache.sharedFamilies, familiesCache.lastFetchErr = prometheus.GetFamilies()
+		familiesCache.lastFetchTimestamp = now
+	}
+
+	return familiesCache.sharedFamilies, familiesCache.lastFetchErr
+}
+
+func (m *module) GetKubeletStats(http *helper.HTTP) ([]byte, error) {
+	m.kubeletStatsCache.lock.Lock()
+	defer m.kubeletStatsCache.lock.Unlock()
+
+	now := time.Now()
+
+	// NOTE: These entries will be never removed, this can be a leak if
+	// metricbeat is used to monitor clusters dynamically created.
+	// (https://github.com/elastic/beats/pull/25640#discussion_r633395213)
+	statsCache := m.kubeletStatsCache.getCacheMapEntry(m.cacheHash)
 
-	if m.familiesCache.lastFetchTimestamp.IsZero() || now.Sub(m.familiesCache.lastFetchTimestamp) > m.Config().Period {
-		m.familiesCache.sharedFamilies, m.familiesCache.lastFetchErr = prometheus.GetFamilies()
-		m.familiesCache.lastFetchTimestamp = now
+	if statsCache.lastFetchTimestamp.IsZero() || now.Sub(statsCache.lastFetchTimestamp) > m.Config().Period {
+		statsCache.sharedStats, statsCache.lastFetchErr = http.FetchContent()
+		statsCache.lastFetchTimestamp = now
 	}
 
-	return m.familiesCache.sharedFamilies, m.familiesCache.lastFetchErr
+	return statsCache.sharedStats, statsCache.lastFetchErr
 }
 
 func generateCacheHash(host []string) (uint64, error) {

metricbeat/module/kubernetes/node/node.go

@@ -18,6 +18,8 @@
 package node
 
 import (
+	"fmt"
+
 	"github.com/pkg/errors"
 
 	"github.com/elastic/beats/v7/libbeat/common"
@@ -26,6 +28,7 @@ import (
 	"github.com/elastic/beats/v7/metricbeat/helper"
 	"github.com/elastic/beats/v7/metricbeat/mb"
 	"github.com/elastic/beats/v7/metricbeat/mb/parse"
+	k8smod "github.com/elastic/beats/v7/metricbeat/module/kubernetes"
 	"github.com/elastic/beats/v7/metricbeat/module/kubernetes/util"
 )
 
@@ -60,6 +63,7 @@ type MetricSet struct {
 	mb.BaseMetricSet
 	http     *helper.HTTP
 	enricher util.Enricher
+	mod      k8smod.Module
 }
 
 // New create a new instance of the MetricSet
@@ -70,11 +74,15 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 	if err != nil {
 		return nil, err
 	}
-
+	mod, ok := base.Module().(k8smod.Module)
+	if !ok {
+		return nil, fmt.Errorf("must be child of kubernetes module")
+	}
 	return &MetricSet{
 		BaseMetricSet: base,
 		http:          http,
 		enricher:      util.NewResourceMetadataEnricher(base, &kubernetes.Node{}, false),
+		mod:           mod,
 	}, nil
 }
 
@@ -84,7 +92,7 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *MetricSet) Fetch(reporter mb.ReporterV2) error {
 	m.enricher.Start()
 
-	body, err := m.http.FetchContent()
+	body, err := m.mod.GetKubeletStats(m.http)
 	if err != nil {
 		return errors.Wrap(err, "error doing HTTP request to fetch 'node' Metricset data")
 

metricbeat/module/kubernetes/pod/pod.go

@@ -18,13 +18,16 @@
 package pod
 
 import (
+	"fmt"
+
 	"github.com/pkg/errors"
 
 	"github.com/elastic/beats/v7/libbeat/common/kubernetes"
 	"github.com/elastic/beats/v7/libbeat/logp"
 	"github.com/elastic/beats/v7/metricbeat/helper"
 	"github.com/elastic/beats/v7/metricbeat/mb"
 	"github.com/elastic/beats/v7/metricbeat/mb/parse"
+	k8smod "github.com/elastic/beats/v7/metricbeat/module/kubernetes"
 	"github.com/elastic/beats/v7/metricbeat/module/kubernetes/util"
 )
 
@@ -59,6 +62,7 @@ type MetricSet struct {
 	mb.BaseMetricSet
 	http     *helper.HTTP
 	enricher util.Enricher
+	mod      k8smod.Module
 }
 
 // New create a new instance of the MetricSet
@@ -69,11 +73,15 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 	if err != nil {
 		return nil, err
 	}
-
+	mod, ok := base.Module().(k8smod.Module)
+	if !ok {
+		return nil, fmt.Errorf("must be child of kubernetes module")
+	}
 	return &MetricSet{
 		BaseMetricSet: base,
 		http:          http,
 		enricher:      util.NewResourceMetadataEnricher(base, &kubernetes.Pod{}, true),
+		mod:           mod,
 	}, nil
 }
 
@@ -83,9 +91,9 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *MetricSet) Fetch(reporter mb.ReporterV2) error {
 	m.enricher.Start()
 
-	body, err := m.http.FetchContent()
+	body, err := m.mod.GetKubeletStats(m.http)
 	if err != nil {
-		return errors.Wrap(err, "error doing HTTP request to fetch 'pod' Metricset data")
+		return errors.Wrap(err, "error fetching shared data for 'pod' Metricset")
 	}
 
 	events, err := eventMapping(body, util.PerfMetrics)

metricbeat/module/kubernetes/state_container/state_container.go

@@ -120,7 +120,7 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *MetricSet) Fetch(reporter mb.ReporterV2) error {
 	m.enricher.Start()
 
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		return errors.Wrap(err, "error getting families")
 	}

metricbeat/module/kubernetes/state_cronjob/state_cronjob.go

@@ -87,7 +87,7 @@ func NewCronJobMetricSet(base mb.BaseMetricSet) (mb.MetricSet, error) {
 //
 // Copied from other kube state metrics.
 func (m *CronJobMetricSet) Fetch(reporter mb.ReporterV2) error {
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		return errors.Wrap(err, "error getting family metrics")
 	}

metricbeat/module/kubernetes/state_daemonset/state_daemonset.go

@@ -101,7 +101,7 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *MetricSet) Fetch(reporter mb.ReporterV2) {
 	m.enricher.Start()
 
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		m.Logger().Error(err)
 		reporter.Error(err)

metricbeat/module/kubernetes/state_deployment/state_deployment.go

@@ -102,7 +102,7 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *MetricSet) Fetch(reporter mb.ReporterV2) {
 	m.enricher.Start()
 
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		m.Logger().Error(err)
 		reporter.Error(err)

metricbeat/module/kubernetes/state_node/state_node.go

@@ -113,7 +113,7 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *MetricSet) Fetch(reporter mb.ReporterV2) error {
 	m.enricher.Start()
 
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		return errors.Wrap(err, "error doing HTTP request to fetch 'state_node' Metricset data")
 	}

metricbeat/module/kubernetes/state_persistentvolume/state_persistentvolume.go

@@ -77,7 +77,7 @@ func NewPersistentVolumeMetricSet(base mb.BaseMetricSet) (mb.MetricSet, error) {
 // Fetch prometheus metrics and treats those prefixed by mb.ModuleDataKey as
 // module rooted fields at the event that gets reported
 func (m *PersistentVolumeMetricSet) Fetch(reporter mb.ReporterV2) {
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		m.Logger().Error(err)
 		reporter.Error(err)

metricbeat/module/kubernetes/state_persistentvolumeclaim/state_persistentvolumeclaim.go

@@ -82,7 +82,7 @@ func NewpersistentvolumeclaimMetricSet(base mb.BaseMetricSet) (mb.MetricSet, err
 // module rooted fields at the event that gets reported
 func (m *persistentvolumeclaimMetricSet) Fetch(reporter mb.ReporterV2) error {
 
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		return err
 	}

metricbeat/module/kubernetes/state_pod/state_pod.go

@@ -104,7 +104,7 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *MetricSet) Fetch(reporter mb.ReporterV2) {
 	m.enricher.Start()
 
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		m.Logger().Error(err)
 		reporter.Error(err)

metricbeat/module/kubernetes/state_replicaset/state_replicaset.go

@@ -102,7 +102,7 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *MetricSet) Fetch(reporter mb.ReporterV2) {
 	m.enricher.Start()
 
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		m.Logger().Error(err)
 		reporter.Error(err)

metricbeat/module/kubernetes/state_resourcequota/state_resourcequota.go

@@ -76,7 +76,7 @@ func NewResourceQuotaMetricSet(base mb.BaseMetricSet) (mb.MetricSet, error) {
 // Fetch prometheus metrics and treats those prefixed by mb.ModuleDataKey as
 // module rooted fields at the event that gets reported
 func (m *ResourceQuotaMetricSet) Fetch(reporter mb.ReporterV2) {
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		m.Logger().Error(err)
 		reporter.Error(err)

metricbeat/module/kubernetes/state_service/state_service.go

@@ -95,7 +95,7 @@ func NewServiceMetricSet(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *ServiceMetricSet) Fetch(reporter mb.ReporterV2) {
 	m.enricher.Start()
 
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		m.Logger().Error(err)
 		reporter.Error(err)

metricbeat/module/kubernetes/state_statefulset/state_statefulset.go

@@ -101,7 +101,7 @@ func New(base mb.BaseMetricSet) (mb.MetricSet, error) {
 func (m *MetricSet) Fetch(reporter mb.ReporterV2) {
 	m.enricher.Start()
 
-	families, err := m.mod.GetSharedFamilies(m.prometheus)
+	families, err := m.mod.GetStateMetricsFamilies(m.prometheus)
 	if err != nil {
 		m.Logger().Error(err)
 		reporter.Error(err)