Use standard collector selectors in target allocator config

.chloggen/feat_targetallocator-selector.yaml

@@ -0,0 +1,18 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. operator, target allocator, github action)
+component: target allocator
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Use standard K8s label selectors for collectors in target allocator config
+
+# One or more tracking issues related to the change
+issues: [2422]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: |
+  This is a breaking change only for users of standalone target allocator. Operator users are unaffected.
+  The operator is still compatible with previous target allocator versions, and will be for the next 3 releases.

cmd/otel-allocator/collector/collector.go

@@ -24,7 +24,6 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/watch"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
@@ -63,11 +62,15 @@ func NewClient(logger logr.Logger, kubeConfig *rest.Config) (*Client, error) {
 	}, nil
 }
 
-func (k *Client) Watch(ctx context.Context, labelMap map[string]string, fn func(collectors map[string]*allocation.Collector)) error {
+func (k *Client) Watch(ctx context.Context, labelSelector *metav1.LabelSelector, fn func(collectors map[string]*allocation.Collector)) error {
 	collectorMap := map[string]*allocation.Collector{}
 
+	selector, err := metav1.LabelSelectorAsSelector(labelSelector)
+	if err != nil {
+		return err
+	}
 	opts := metav1.ListOptions{
-		LabelSelector: labels.SelectorFromSet(labelMap).String(),
+		LabelSelector: selector.String(),
 	}
 	pods, err := k.k8sClient.CoreV1().Pods(ns).List(ctx, opts)
 	if err != nil {

cmd/otel-allocator/collector/collector_test.go

@@ -28,7 +28,6 @@ import (
 	"github.com/stretchr/testify/assert"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/client-go/kubernetes/fake"
 
 	"github.com/open-telemetry/opentelemetry-operator/cmd/otel-allocator/allocation"
@@ -42,14 +41,16 @@ func getTestClient() (Client, watch.Interface) {
 		close:     make(chan struct{}),
 		log:       logger,
 	}
-
-	labelMap := map[string]string{
-		"app.kubernetes.io/instance":   "default.test",
-		"app.kubernetes.io/managed-by": "opentelemetry-operator",
+	labelSelector := metav1.LabelSelector{
+		MatchLabels: map[string]string{
+			"app.kubernetes.io/instance":   "default.test",
+			"app.kubernetes.io/managed-by": "opentelemetry-operator",
+		},
 	}
+	selector, _ := metav1.LabelSelectorAsSelector(&labelSelector)
 
 	opts := metav1.ListOptions{
-		LabelSelector: labels.SelectorFromSet(labelMap).String(),
+		LabelSelector: selector.String(),
 	}
 	watcher, err := kubeClient.k8sClient.CoreV1().Pods("test-ns").Watch(context.Background(), opts)
 	if err != nil {

cmd/otel-allocator/config/config.go

@@ -27,6 +27,7 @@ import (
 	_ "github.com/prometheus/prometheus/discovery/install"
 	"github.com/spf13/pflag"
 	"gopkg.in/yaml.v2"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/klog/v2"
@@ -39,17 +40,17 @@ const DefaultConfigFilePath string = "/conf/targetallocator.yaml"
 const DefaultCRScrapeInterval model.Duration = model.Duration(time.Second * 30)
 
 type Config struct {
-	ListenAddr             string             `yaml:"listen_addr,omitempty"`
-	KubeConfigFilePath     string             `yaml:"kube_config_file_path,omitempty"`
-	ClusterConfig          *rest.Config       `yaml:"-"`
-	RootLogger             logr.Logger        `yaml:"-"`
-	LabelSelector          map[string]string  `yaml:"label_selector,omitempty"`
-	PromConfig             *promconfig.Config `yaml:"config"`
-	AllocationStrategy     *string            `yaml:"allocation_strategy,omitempty"`
-	FilterStrategy         *string            `yaml:"filter_strategy,omitempty"`
-	PrometheusCR           PrometheusCRConfig `yaml:"prometheus_cr,omitempty"`
-	PodMonitorSelector     map[string]string  `yaml:"pod_monitor_selector,omitempty"`
-	ServiceMonitorSelector map[string]string  `yaml:"service_monitor_selector,omitempty"`
+	ListenAddr             string                `yaml:"listen_addr,omitempty"`
+	KubeConfigFilePath     string                `yaml:"kube_config_file_path,omitempty"`
+	ClusterConfig          *rest.Config          `yaml:"-"`
+	RootLogger             logr.Logger           `yaml:"-"`
+	CollectorSelector      *metav1.LabelSelector `yaml:"collector_selector,omitempty"`
+	PromConfig             *promconfig.Config    `yaml:"config"`
+	AllocationStrategy     *string               `yaml:"allocation_strategy,omitempty"`
+	FilterStrategy         *string               `yaml:"filter_strategy,omitempty"`
+	PrometheusCR           PrometheusCRConfig    `yaml:"prometheus_cr,omitempty"`
+	PodMonitorSelector     map[string]string     `yaml:"pod_monitor_selector,omitempty"`
+	ServiceMonitorSelector map[string]string     `yaml:"service_monitor_selector,omitempty"`
 }
 
 type PrometheusCRConfig struct {
@@ -114,7 +115,6 @@ func LoadFromCLI(target *Config, flagSet *pflag.FlagSet) error {
 }
 
 func unmarshal(cfg *Config, configFile string) error {
-
 	yamlFile, err := os.ReadFile(configFile)
 	if err != nil {
 		return err

cmd/otel-allocator/config/config_test.go

@@ -21,6 +21,7 @@ import (
 
 	commonconfig "github.com/prometheus/common/config"
 	promconfig "github.com/prometheus/prometheus/config"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/prometheus/discovery"
@@ -44,9 +45,11 @@ func TestLoad(t *testing.T) {
 				file: "./testdata/config_test.yaml",
 			},
 			want: Config{
-				LabelSelector: map[string]string{
-					"app.kubernetes.io/instance":   "default.test",
-					"app.kubernetes.io/managed-by": "opentelemetry-operator",
+				CollectorSelector: &metav1.LabelSelector{
+					MatchLabels: map[string]string{
+						"app.kubernetes.io/instance":   "default.test",
+						"app.kubernetes.io/managed-by": "opentelemetry-operator",
+					},
 				},
 				PrometheusCR: PrometheusCRConfig{
 					ScrapeInterval: model.Duration(time.Second * 60),
@@ -108,9 +111,11 @@ func TestLoad(t *testing.T) {
 				file: "./testdata/pod_service_selector_test.yaml",
 			},
 			want: Config{
-				LabelSelector: map[string]string{
-					"app.kubernetes.io/instance":   "default.test",
-					"app.kubernetes.io/managed-by": "opentelemetry-operator",
+				CollectorSelector: &metav1.LabelSelector{
+					MatchLabels: map[string]string{
+						"app.kubernetes.io/instance":   "default.test",
+						"app.kubernetes.io/managed-by": "opentelemetry-operator",
+					},
 				},
 				PrometheusCR: PrometheusCRConfig{
 					ScrapeInterval: DefaultCRScrapeInterval,

cmd/otel-allocator/config/testdata/config_test.yaml

@@ -1,6 +1,7 @@
-label_selector:
-  app.kubernetes.io/instance: default.test
-  app.kubernetes.io/managed-by: opentelemetry-operator
+collector_selector:
+  matchlabels:
+    app.kubernetes.io/instance: default.test
+    app.kubernetes.io/managed-by: opentelemetry-operator
 prometheus_cr:
   scrape_interval: 60s
 config:

cmd/otel-allocator/config/testdata/pod_service_selector_test.yaml

@@ -1,6 +1,7 @@
-label_selector:
-  app.kubernetes.io/instance: default.test
-  app.kubernetes.io/managed-by: opentelemetry-operator
+collector_selector:
+  matchlabels:
+    app.kubernetes.io/instance: default.test
+    app.kubernetes.io/managed-by: opentelemetry-operator
 pod_monitor_selector:
   release: test
 service_monitor_selector:

cmd/otel-allocator/main.go

@@ -149,7 +149,7 @@ func main() {
 		})
 	runGroup.Add(
 		func() error {
-			err := collectorWatcher.Watch(ctx, cfg.LabelSelector, allocator.SetCollectors)
+			err := collectorWatcher.Watch(ctx, cfg.CollectorSelector, allocator.SetCollectors)
 			setupLog.Info("Collector watcher exited")
 			return err
 		},

cmd/otel-allocator/target/testdata/test.yaml

@@ -1,6 +1,7 @@
-label_selector:
-  app.kubernetes.io/instance: default.test
-  app.kubernetes.io/managed-by: opentelemetry-operator
+collector_selector:
+  matchlabels:
+    app.kubernetes.io/instance: default.test
+    app.kubernetes.io/managed-by: opentelemetry-operator
 config:
   scrape_configs:
   - job_name: prometheus

cmd/otel-allocator/target/testdata/test_update.yaml

@@ -1,6 +1,7 @@
-label_selector:
-  app.kubernetes.io/instance: default.test
-  app.kubernetes.io/managed-by: opentelemetry-operator
+collector_selector:
+  matchlabels:
+    app.kubernetes.io/instance: default.test
+    app.kubernetes.io/managed-by: opentelemetry-operator
 config:
   scrape_configs:
     - job_name: prometheus

controllers/builder_test.go

@@ -1316,7 +1316,36 @@ service:
 						Annotations: nil,
 					},
 					Data: map[string]string{
-						"targetallocator.yaml": "allocation_strategy: least-weighted\nconfig:\n  scrape_configs:\n  - job_name: example\n    metric_relabel_configs:\n    - replacement: $1_$2\n      source_labels:\n      - job\n      target_label: job\n    relabel_configs:\n    - replacement: my_service_$1\n      source_labels:\n      - __meta_service_id\n      target_label: job\n    - replacement: $1\n      source_labels:\n      - __meta_service_name\n      target_label: instance\nlabel_selector:\n  app.kubernetes.io/component: opentelemetry-collector\n  app.kubernetes.io/instance: test.test\n  app.kubernetes.io/managed-by: opentelemetry-operator\n  app.kubernetes.io/part-of: opentelemetry\n",
+						"targetallocator.yaml": `allocation_strategy: least-weighted
+collector_selector:
+  matchlabels:
+    app.kubernetes.io/component: opentelemetry-collector
+    app.kubernetes.io/instance: test.test
+    app.kubernetes.io/managed-by: opentelemetry-operator
+    app.kubernetes.io/part-of: opentelemetry
+config:
+  scrape_configs:
+  - job_name: example
+    metric_relabel_configs:
+    - replacement: $1_$2
+      source_labels:
+      - job
+      target_label: job
+    relabel_configs:
+    - replacement: my_service_$1
+      source_labels:
+      - __meta_service_id
+      target_label: job
+    - replacement: $1
+      source_labels:
+      - __meta_service_name
+      target_label: instance
+label_selector:
+  app.kubernetes.io/component: opentelemetry-collector
+  app.kubernetes.io/instance: test.test
+  app.kubernetes.io/managed-by: opentelemetry-operator
+  app.kubernetes.io/part-of: opentelemetry
+`,
 					},
 				},
 				&appsv1.Deployment{
@@ -1348,7 +1377,7 @@ service:
 									"app.kubernetes.io/version":    "latest",
 								},
 								Annotations: map[string]string{
-									"opentelemetry-targetallocator-config/hash": "4d1911fd40106e9e2dd3d928f067a6c8c9eab0c569f737ba3701c6f5a9aad6d7",
+									"opentelemetry-targetallocator-config/hash": "20c09760c240d08287ff05bd2375985220b577d938e82efd85467e17174690e0",
 								},
 							},
 							Spec: corev1.PodSpec{
@@ -1676,7 +1705,36 @@ service:
 						Annotations: nil,
 					},
 					Data: map[string]string{
-						"targetallocator.yaml": "allocation_strategy: least-weighted\nconfig:\n  scrape_configs:\n  - job_name: example\n    metric_relabel_configs:\n    - replacement: $1_$2\n      source_labels:\n      - job\n      target_label: job\n    relabel_configs:\n    - replacement: my_service_$1\n      source_labels:\n      - __meta_service_id\n      target_label: job\n    - replacement: $1\n      source_labels:\n      - __meta_service_name\n      target_label: instance\nlabel_selector:\n  app.kubernetes.io/component: opentelemetry-collector\n  app.kubernetes.io/instance: test.test\n  app.kubernetes.io/managed-by: opentelemetry-operator\n  app.kubernetes.io/part-of: opentelemetry\n",
+						"targetallocator.yaml": `allocation_strategy: least-weighted
+collector_selector:
+  matchlabels:
+    app.kubernetes.io/component: opentelemetry-collector
+    app.kubernetes.io/instance: test.test
+    app.kubernetes.io/managed-by: opentelemetry-operator
+    app.kubernetes.io/part-of: opentelemetry
+config:
+  scrape_configs:
+  - job_name: example
+    metric_relabel_configs:
+    - replacement: $1_$2
+      source_labels:
+      - job
+      target_label: job
+    relabel_configs:
+    - replacement: my_service_$1
+      source_labels:
+      - __meta_service_id
+      target_label: job
+    - replacement: $1
+      source_labels:
+      - __meta_service_name
+      target_label: instance
+label_selector:
+  app.kubernetes.io/component: opentelemetry-collector
+  app.kubernetes.io/instance: test.test
+  app.kubernetes.io/managed-by: opentelemetry-operator
+  app.kubernetes.io/part-of: opentelemetry
+`,
 					},
 				},
 				&appsv1.Deployment{
@@ -1708,7 +1766,7 @@ service:
 									"app.kubernetes.io/version":    "latest",
 								},
 								Annotations: map[string]string{
-									"opentelemetry-targetallocator-config/hash": "4d1911fd40106e9e2dd3d928f067a6c8c9eab0c569f737ba3701c6f5a9aad6d7",
+									"opentelemetry-targetallocator-config/hash": "20c09760c240d08287ff05bd2375985220b577d938e82efd85467e17174690e0",
 								},
 							},
 							Spec: corev1.PodSpec{

controllers/reconcile_test.go

@@ -443,6 +443,14 @@ func TestOpenTelemetryCollectorReconciler_Reconcile(t *testing.T) {
 							assert.NoError(t, err)
 
 							taConfig := make(map[interface{}]interface{})
+							taConfig["collector_selector"] = map[string]any{
+								"matchlabels": map[string]string{
+									"app.kubernetes.io/instance":   "default.test",
+									"app.kubernetes.io/managed-by": "opentelemetry-operator",
+									"app.kubernetes.io/component":  "opentelemetry-collector",
+									"app.kubernetes.io/part-of":    "opentelemetry",
+								},
+							}
 							taConfig["label_selector"] = map[string]string{
 								"app.kubernetes.io/instance":   "default.test",
 								"app.kubernetes.io/managed-by": "opentelemetry-operator",

internal/manifests/targetallocator/configmap.go

@@ -44,7 +44,13 @@ func ConfigMap(params manifests.Params) (*corev1.ConfigMap, error) {
 
 	taConfig := make(map[interface{}]interface{})
 	prometheusCRConfig := make(map[interface{}]interface{})
-	taConfig["label_selector"] = manifestutils.SelectorLabels(params.OtelCol.ObjectMeta, collector.ComponentOpenTelemetryCollector)
+	collectorSelectorLabels := manifestutils.SelectorLabels(params.OtelCol.ObjectMeta, collector.ComponentOpenTelemetryCollector)
+	taConfig["collector_selector"] = map[string]any{
+		"matchlabels": collectorSelectorLabels,
+	}
+	// The below instruction is here for compatibility with the previous target allocator version
+	// TODO: Drop it after 3 more versions
+	taConfig["label_selector"] = collectorSelectorLabels
 	// We only take the "config" from the returned object, if it's present
 	if prometheusConfig, ok := prometheusReceiverConfig["config"]; ok {
 		taConfig["config"] = prometheusConfig

internal/manifests/targetallocator/configmap_test.go

@@ -40,6 +40,12 @@ func TestDesiredConfigMap(t *testing.T) {
 
 		expectedData := map[string]string{
 			"targetallocator.yaml": `allocation_strategy: least-weighted
+collector_selector:
+  matchlabels:
+    app.kubernetes.io/component: opentelemetry-collector
+    app.kubernetes.io/instance: default.my-instance
+    app.kubernetes.io/managed-by: opentelemetry-operator
+    app.kubernetes.io/part-of: opentelemetry
 config:
   scrape_configs:
   - job_name: otel-collector
@@ -76,6 +82,12 @@ label_selector:
 
 		expectedData := map[string]string{
 			"targetallocator.yaml": `allocation_strategy: least-weighted
+collector_selector:
+  matchlabels:
+    app.kubernetes.io/component: opentelemetry-collector
+    app.kubernetes.io/instance: default.my-instance
+    app.kubernetes.io/managed-by: opentelemetry-operator
+    app.kubernetes.io/part-of: opentelemetry
 config:
   scrape_configs:
   - job_name: otel-collector
@@ -122,6 +134,12 @@ service_monitor_selector:
 
 		expectedData := map[string]string{
 			"targetallocator.yaml": `allocation_strategy: least-weighted
+collector_selector:
+  matchlabels:
+    app.kubernetes.io/component: opentelemetry-collector
+    app.kubernetes.io/instance: default.my-instance
+    app.kubernetes.io/managed-by: opentelemetry-operator
+    app.kubernetes.io/part-of: opentelemetry
 config:
   scrape_configs:
   - job_name: otel-collector