[receiver/k8s_cluster] Do not store unused service data in k8s API ca…

…che (open-telemetry#23434)

To reduce RAM utilization.

Resolves
open-telemetry#23433

This is the last PR to reduce the memory footprint of k8s API informers.
Other objects are more static and usually don't have a lot of instances
in user clusters, so there is no need to reduce their size.

receiver/k8sclusterreceiver/informer_transform.go

@@ -14,6 +14,7 @@ import (
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/node"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/pod"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/replicaset"
+ "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/service"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/statefulset"
 )
 
@@ -35,6 +36,8 @@ func transformObject(object interface{}) (interface{}, error) {
  return demonset.Transform(o), nil
  case *appsv1.StatefulSet:
  return statefulset.Transform(o), nil
+ case *corev1.Service:
+ return service.Transform(o), nil
  }
  return object, nil
 }

receiver/k8sclusterreceiver/informer_transform_test.go

@@ -93,6 +93,25 @@ func TestTransformObject(t *testing.T) {
  },
  same: false,
  },
+ {
+ name: "service",
+ object: &corev1.Service{
+ Spec: corev1.ServiceSpec{
+ Selector: map[string]string{
+ "app": "my-app",
+ },
+ Type: corev1.ServiceTypeClusterIP,
+ },
+ },
+ want: &corev1.Service{
+ Spec: corev1.ServiceSpec{
+ Selector: map[string]string{
+ "app": "my-app",
+ },
+ },
+ },
+ same: false,
+ },
  {
  // This is a case where we don't transform the object.
  name: "hpa",

receiver/k8sclusterreceiver/internal/pod/pods.go

@@ -4,7 +4,6 @@
 package pod // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/pod"
 
 import (
- "fmt"
  "strings"
  "time"
 
@@ -17,7 +16,6 @@ import (
  batchv1 "k8s.io/api/batch/v1"
  corev1 "k8s.io/api/core/v1"
  v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
- "k8s.io/apimachinery/pkg/labels"
  "k8s.io/apimachinery/pkg/types"
  "k8s.io/client-go/tools/cache"
 
@@ -26,6 +24,7 @@ import (
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/constants"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/container"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/metadata"
+ "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/service"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/utils"
 )
 
@@ -184,7 +183,7 @@ func GetMetadata(pod *corev1.Pod, mc *metadata.Store, logger *zap.Logger) map[ex
  }
 
  if mc.Services != nil {
- meta = maps.MergeStringMaps(meta, getPodServiceTags(pod, mc.Services))
+ meta = maps.MergeStringMaps(meta, service.GetPodServiceTags(pod, mc.Services))
  }
 
  if mc.Jobs != nil {
@@ -268,21 +267,6 @@ func logError(err error, ref *v1.OwnerReference, podUID types.UID, logger *zap.L
  )
 }
 
-// getPodServiceTags returns a set of services associated with the pod.
-func getPodServiceTags(pod *corev1.Pod, services cache.Store) map[string]string {
- properties := map[string]string{}
-
- for _, ser := range services.List() {
- serObj := ser.(*corev1.Service)
- if serObj.Namespace == pod.Namespace &&
- labels.Set(serObj.Spec.Selector).AsSelectorPreValidated().Matches(labels.Set(pod.Labels)) {
- properties[fmt.Sprintf("%s%s", constants.K8sServicePrefix, serObj.Name)] = ""
- }
- }
-
- return properties
-}
-
 // getWorkloadProperties returns workload metadata for provided owner reference.
 func getWorkloadProperties(ref *v1.OwnerReference, labelKey string) map[string]string {
  uidKey := metadata.GetOTelUIDFromKind(strings.ToLower(ref.Kind))

receiver/k8sclusterreceiver/internal/service/service.go

@@ -0,0 +1,40 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package service // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/service"
+import (
+ "fmt"
+
+ corev1 "k8s.io/api/core/v1"
+ "k8s.io/apimachinery/pkg/labels"
+ "k8s.io/client-go/tools/cache"
+
+ "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/constants"
+ "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sclusterreceiver/internal/metadata"
+)
+
+// Transform transforms the pod to remove the fields that we don't use to reduce RAM utilization.
+// IMPORTANT: Make sure to update this function before using new service fields.
+func Transform(service *corev1.Service) *corev1.Service {
+ return &corev1.Service{
+ ObjectMeta: metadata.TransformObjectMeta(service.ObjectMeta),
+ Spec: corev1.ServiceSpec{
+ Selector: service.Spec.Selector,
+ },
+ }
+}
+
+// GetPodServiceTags returns a set of services associated with the pod.
+func GetPodServiceTags(pod *corev1.Pod, services cache.Store) map[string]string {
+ properties := map[string]string{}
+
+ for _, ser := range services.List() {
+ serObj := ser.(*corev1.Service)
+ if serObj.Namespace == pod.Namespace &&
+ labels.Set(serObj.Spec.Selector).AsSelectorPreValidated().Matches(labels.Set(pod.Labels)) {
+ properties[fmt.Sprintf("%s%s", constants.K8sServicePrefix, serObj.Name)] = ""
+ }
+ }
+
+ return properties
+}

receiver/k8sclusterreceiver/internal/service/service_test.go

@@ -0,0 +1,55 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package service
+
+import (
+ "testing"
+
+ "github.com/stretchr/testify/assert"
+ corev1 "k8s.io/api/core/v1"
+ metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func TestTransform(t *testing.T) {
+ originalService := &corev1.Service{
+ ObjectMeta: metav1.ObjectMeta{
+ Name: "my-service",
+ Namespace: "default",
+ Labels: map[string]string{
+ "app": "my-app",
+ },
+ Annotations: map[string]string{
+ "annotation1": "value1",
+ },
+ },
+ Spec: corev1.ServiceSpec{
+ Selector: map[string]string{
+ "app": "my-app",
+ },
+ Ports: []corev1.ServicePort{
+ {
+ Name: "http",
+ Port: 80,
+ Protocol: corev1.ProtocolTCP,
+ },
+ },
+ Type: corev1.ServiceTypeClusterIP,
+ },
+ }
+ wantService := &corev1.Service{
+ ObjectMeta: metav1.ObjectMeta{
+ Name: "my-service",
+ Namespace: "default",
+ Labels: map[string]string{
+ "app": "my-app",
+ },
+ },
+ Spec: corev1.ServiceSpec{
+ Selector: map[string]string{
+ "app": "my-app",
+ },
+ },
+ }
+ assert.EqualValues(t, wantService, Transform(originalService))
+}