/
hpa.go
378 lines (326 loc) · 11.9 KB
/
hpa.go
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package provider
import (
"context"
"errors"
"reflect"
"sync"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promauto"
log "github.com/sirupsen/logrus"
autoscalingv2 "k8s.io/api/autoscaling/v2"
apiv1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/types"
"k8s.io/client-go/kubernetes"
kube_record "k8s.io/client-go/tools/record"
"k8s.io/metrics/pkg/apis/custom_metrics"
"k8s.io/metrics/pkg/apis/external_metrics"
"sigs.k8s.io/custom-metrics-apiserver/pkg/provider"
"github.com/zalando-incubator/kube-metrics-adapter/pkg/collector"
"github.com/zalando-incubator/kube-metrics-adapter/pkg/recorder"
)
var (
// CollectionSuccesses is the total number of successful collections.
CollectionSuccesses = promauto.NewCounter(prometheus.CounterOpts{
Name: "kube_metrics_adapter_collections_success",
Help: "The total number of successful collections",
})
// CollectionErrors is the total number of failed collection attempts.
CollectionErrors = promauto.NewCounter(prometheus.CounterOpts{
Name: "kube_metrics_adapter_collections_error",
Help: "The total number of failed collection attempts",
})
// UpdateSuccesses is the total number of successful HPA updates.
UpdateSuccesses = promauto.NewCounter(prometheus.CounterOpts{
Name: "kube_metrics_adapter_updates_success",
Help: "The total number of successful HPA updates",
})
// UpdateErrors is the total number of failed HPA update attempts.
UpdateErrors = promauto.NewCounter(prometheus.CounterOpts{
Name: "kube_metrics_adapter_updates_error",
Help: "The total number of failed HPA update attempts",
})
)
// HPAProvider is a base provider for initializing metric collectors based on
// HPA resources.
type HPAProvider struct {
client kubernetes.Interface
interval time.Duration
collectorScheduler *CollectorScheduler
collectorInterval time.Duration
metricSink chan metricCollection
hpaCache map[resourceReference]autoscalingv2.HorizontalPodAutoscaler
metricStore *MetricStore
collectorFactory *collector.CollectorFactory
recorder kube_record.EventRecorder
logger *log.Entry
disregardIncompatibleHPAs bool
gcInterval time.Duration
}
// metricCollection is a container for sending collected metrics across a
// channel.
type metricCollection struct {
Values []collector.CollectedMetric
Error error
}
// NewHPAProvider initializes a new HPAProvider.
func NewHPAProvider(client kubernetes.Interface, interval, collectorInterval time.Duration, collectorFactory *collector.CollectorFactory, disregardIncompatibleHPAs bool, metricsTTL time.Duration, gcInterval time.Duration) *HPAProvider {
metricsc := make(chan metricCollection)
return &HPAProvider{
client: client,
interval: interval,
collectorInterval: collectorInterval,
metricSink: metricsc,
metricStore: NewMetricStore(func() time.Time {
return time.Now().UTC().Add(metricsTTL)
}),
collectorFactory: collectorFactory,
recorder: recorder.CreateEventRecorder(client),
logger: log.WithFields(log.Fields{"provider": "hpa"}),
disregardIncompatibleHPAs: disregardIncompatibleHPAs,
gcInterval: gcInterval,
}
}
// Run runs the HPA resource discovery and metric collection.
func (p *HPAProvider) Run(ctx context.Context) {
// initialize collector table
p.collectorScheduler = NewCollectorScheduler(ctx, p.metricSink)
go p.collectMetrics(ctx)
for {
err := p.updateHPAs()
if err != nil {
p.logger.Error(err)
UpdateErrors.Inc()
} else {
UpdateSuccesses.Inc()
}
select {
case <-time.After(p.interval):
case <-ctx.Done():
p.logger.Info("Stopped HPA provider.")
return
}
}
}
// updateHPAs discovers all HPA resources and sets up metric collectors for new
// HPAs.
func (p *HPAProvider) updateHPAs() error {
p.logger.Info("Looking for HPAs")
hpas, err := p.client.AutoscalingV2().HorizontalPodAutoscalers(metav1.NamespaceAll).List(context.TODO(), metav1.ListOptions{})
if err != nil {
return err
}
newHPACache := make(map[resourceReference]autoscalingv2.HorizontalPodAutoscaler, len(hpas.Items))
newHPAs := 0
for _, hpa := range hpas.Items {
hpa := *hpa.DeepCopy()
resourceRef := resourceReference{
Name: hpa.Name,
Namespace: hpa.Namespace,
}
cachedHPA, ok := p.hpaCache[resourceRef]
hpaUpdated := !equalHPA(cachedHPA, hpa)
if !ok || hpaUpdated {
// if the hpa has changed then remove the previous
// scheduled collector.
if hpaUpdated {
p.logger.Infof("Removing previously scheduled metrics collector: %s", resourceRef)
p.collectorScheduler.Remove(resourceRef)
}
metricConfigs, err := collector.ParseHPAMetrics(&hpa)
if err != nil {
p.logger.Errorf("Failed to parse HPA metrics: %v", err)
continue
}
cache := true
for _, config := range metricConfigs {
interval := config.Interval
if interval == 0 {
interval = p.collectorInterval
}
c, err := p.collectorFactory.NewCollector(&hpa, config, interval)
if err != nil {
// Only log when it's not a PluginNotFoundError AND flag disregardIncompatibleHPAs is true
if !(errors.Is(err, &collector.PluginNotFoundError{}) && p.disregardIncompatibleHPAs) {
p.recorder.Eventf(&hpa, apiv1.EventTypeWarning, "CreateNewMetricsCollector", "Failed to create new metrics collector: %v", err)
}
cache = false
continue
}
p.logger.Infof("Adding new metrics collector: %T", c)
p.collectorScheduler.Add(resourceRef, config.MetricTypeName, c)
}
newHPAs++
// if we get an error setting up the collectors for the
// HPA, don't cache it, but try again later.
if !cache {
continue
}
}
newHPACache[resourceRef] = hpa
}
for ref := range p.hpaCache {
if _, ok := newHPACache[ref]; ok {
continue
}
p.logger.Infof("Removing previously scheduled metrics collector: %s", ref)
p.collectorScheduler.Remove(ref)
}
p.logger.Infof("Found %d new/updated HPA(s)", newHPAs)
p.hpaCache = newHPACache
return nil
}
// equalHPA returns true if two HPAs are identical (apart from their status).
func equalHPA(a, b autoscalingv2.HorizontalPodAutoscaler) bool {
// reset resource version to not compare it since this will change
// whenever the status of the object is updated. We only want to
// compare the metadata and the spec.
a.ObjectMeta.ResourceVersion = ""
b.ObjectMeta.ResourceVersion = ""
return reflect.DeepEqual(a.ObjectMeta, b.ObjectMeta) && reflect.DeepEqual(a.Spec, b.Spec)
}
// collectMetrics collects all metrics from collectors and manages a central
// metric store.
func (p *HPAProvider) collectMetrics(ctx context.Context) {
// run garbage collection every 10 minutes
go func(ctx context.Context) {
for {
select {
case <-time.After(p.gcInterval):
p.metricStore.RemoveExpired()
case <-ctx.Done():
p.logger.Info("Stopped metrics store garbage collection.")
return
}
}
}(ctx)
for {
select {
case collection := <-p.metricSink:
if collection.Error != nil {
p.logger.Errorf("Failed to collect metrics: %v", collection.Error)
CollectionErrors.Inc()
} else {
CollectionSuccesses.Inc()
}
p.logger.Infof("Collected %d new metric(s)", len(collection.Values))
for _, value := range collection.Values {
switch value.Type {
case autoscalingv2.ObjectMetricSourceType, autoscalingv2.PodsMetricSourceType:
p.logger.Infof("Collected new custom metric '%s' (%s) for %s %s/%s",
value.Custom.Metric.Name,
value.Custom.Value.String(),
value.Custom.DescribedObject.Kind,
value.Custom.DescribedObject.Namespace,
value.Custom.DescribedObject.Name,
)
case autoscalingv2.ExternalMetricSourceType:
p.logger.Infof("Collected new external metric '%s/%s' (%s) [%s]",
value.Namespace,
value.External.MetricName,
value.External.Value.String(),
labels.Set(value.External.MetricLabels).String(),
)
}
p.metricStore.Insert(value)
}
case <-ctx.Done():
p.logger.Info("Stopped metrics collection.")
return
}
}
}
// GetMetricByName gets a single metric by name.
func (p *HPAProvider) GetMetricByName(ctx context.Context, name types.NamespacedName, info provider.CustomMetricInfo, metricSelector labels.Selector) (*custom_metrics.MetricValue, error) {
metric := p.metricStore.GetMetricsByName(ctx, name, info, metricSelector)
if metric == nil {
return nil, provider.NewMetricNotFoundForError(info.GroupResource, info.Metric, name.Name)
}
return metric, nil
}
// GetMetricBySelector returns metrics for namespaced resources by
// label selector.
func (p *HPAProvider) GetMetricBySelector(ctx context.Context, namespace string, selector labels.Selector, info provider.CustomMetricInfo, metricSelector labels.Selector) (*custom_metrics.MetricValueList, error) {
return p.metricStore.GetMetricsBySelector(ctx, objectNamespace(namespace), selector, info), nil
}
// ListAllMetrics list all available metrics from the provicer.
func (p *HPAProvider) ListAllMetrics() []provider.CustomMetricInfo {
return p.metricStore.ListAllMetrics()
}
func (p *HPAProvider) GetExternalMetric(ctx context.Context, namespace string, metricSelector labels.Selector, info provider.ExternalMetricInfo) (*external_metrics.ExternalMetricValueList, error) {
return p.metricStore.GetExternalMetric(ctx, objectNamespace(namespace), metricSelector, info)
}
func (p *HPAProvider) ListAllExternalMetrics() []provider.ExternalMetricInfo {
return p.metricStore.ListAllExternalMetrics()
}
type resourceReference struct {
Name string
Namespace string
}
// CollectorScheduler is a scheduler for running metric collection jobs.
// It keeps track of all running collectors and stops them if they are to be
// removed.
type CollectorScheduler struct {
ctx context.Context
table map[resourceReference]map[collector.MetricTypeName]context.CancelFunc
metricSink chan<- metricCollection
sync.RWMutex
}
// NewCollectorScheudler initializes a new CollectorScheduler.
func NewCollectorScheduler(ctx context.Context, metricsc chan<- metricCollection) *CollectorScheduler {
return &CollectorScheduler{
ctx: ctx,
table: map[resourceReference]map[collector.MetricTypeName]context.CancelFunc{},
metricSink: metricsc,
}
}
// Add adds a new collector to the collector scheduler. Once the collector is
// added it will be started to collect metrics.
func (t *CollectorScheduler) Add(resourceRef resourceReference, typeName collector.MetricTypeName, metricCollector collector.Collector) {
t.Lock()
defer t.Unlock()
collectors, ok := t.table[resourceRef]
if !ok {
collectors = map[collector.MetricTypeName]context.CancelFunc{}
t.table[resourceRef] = collectors
}
if cancelCollector, ok := collectors[typeName]; ok {
// stop old collector
cancelCollector()
}
ctx, cancel := context.WithCancel(t.ctx)
collectors[typeName] = cancel
// start runner for new collector
go collectorRunner(ctx, metricCollector, t.metricSink)
}
// collectorRunner runs a collector at the desirec interval. If the passed
// context is canceled the collection will be stopped.
func collectorRunner(ctx context.Context, collector collector.Collector, metricsc chan<- metricCollection) {
for {
values, err := collector.GetMetrics()
metricsc <- metricCollection{
Values: values,
Error: err,
}
select {
case <-time.After(collector.Interval()):
case <-ctx.Done():
log.Info("stopping collector runner...")
return
}
}
}
// Remove removes a collector from the Collector scheduler. The collector is
// stopped before it's removed.
func (t *CollectorScheduler) Remove(resourceRef resourceReference) {
t.Lock()
defer t.Unlock()
if collectors, ok := t.table[resourceRef]; ok {
for _, cancelCollector := range collectors {
cancelCollector()
}
delete(t.table, resourceRef)
}
}