Fix embedded TargetAllocator CR labels (#4026)

* Fix embedded TargetAllocator CR labels

* Add changelog entry

Author: swiatekm

.chloggen/fix_ta-cr-labels-annotations.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. collector, target allocator, auto-instrumentation, opamp, 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: Add app.kubernetes.io/managed-by label to Target Allocator CRs created by the Collector CR
+
+# One or more tracking issues related to the change
+issues: [4025]
+
+# (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:

internal/controllers/builder_test.go

@@ -3136,7 +3136,9 @@ service:
 					ObjectMeta: metav1.ObjectMeta{
 						Name:      "test",
 						Namespace: "test",
-						Labels:    nil,
+						Labels: map[string]string{
+							"app.kubernetes.io/managed-by": "opentelemetry-operator",
+						},
 					},
 					Spec: v1alpha1.TargetAllocatorSpec{
 						FilterStrategy:     v1beta1.TargetAllocatorFilterStrategyRelabelConfig,
@@ -3378,7 +3380,9 @@ service:
 					ObjectMeta: metav1.ObjectMeta{
 						Name:      "test",
 						Namespace: "test",
-						Labels:    nil,
+						Labels: map[string]string{
+							"app.kubernetes.io/managed-by": "opentelemetry-operator",
+						},
 					},
 					Spec: v1alpha1.TargetAllocatorSpec{
 						FilterStrategy: v1beta1.TargetAllocatorFilterStrategyRelabelConfig,

internal/controllers/reconcile_test.go

@@ -533,7 +533,9 @@ func TestOpenTelemetryCollectorReconciler_Reconcile(t *testing.T) {
 								ObjectMeta: metav1.ObjectMeta{
 									Name:      params.Name,
 									Namespace: params.Namespace,
-									Labels:    nil,
+									Labels: map[string]string{
+										"app.kubernetes.io/managed-by": "opentelemetry-operator",
+									},
 								},
 								Spec: v1alpha1.TargetAllocatorSpec{
 									OpenTelemetryCommonFields: v1beta1.OpenTelemetryCommonFields{},

internal/manifests/collector/targetallocator.go

@@ -4,6 +4,8 @@
 package collector
 
 import (
+	"maps"
+
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	"github.com/open-telemetry/opentelemetry-operator/apis/v1alpha1"
@@ -13,18 +15,25 @@ import (
 
 // TargetAllocator builds the TargetAllocator CR for the given instance.
 func TargetAllocator(params manifests.Params) (*v1alpha1.TargetAllocator, error) {
-
 	taSpec := params.OtelCol.Spec.TargetAllocator
 	if !taSpec.Enabled {
 		return nil, nil
 	}
 
+	// setting all the labels normally here leads to some undesirable results, like the name label being wrong
+	// instead, only set managed-by and leave everything else as-is
+	labels := maps.Clone(params.OtelCol.Labels)
+	if labels == nil {
+		labels = make(map[string]string, 1)
+	}
+	labels["app.kubernetes.io/managed-by"] = "opentelemetry-operator"
+
 	return &v1alpha1.TargetAllocator{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:        params.OtelCol.Name,
 			Namespace:   params.OtelCol.Namespace,
 			Annotations: params.OtelCol.Annotations,
-			Labels:      params.OtelCol.Labels,
+			Labels:      labels,
 		},
 		Spec: v1alpha1.TargetAllocatorSpec{
 			OpenTelemetryCommonFields: v1beta1.OpenTelemetryCommonFields{

internal/manifests/collector/targetallocator_test.go

@@ -29,6 +29,17 @@ func TestTargetAllocator(t *testing.T) {
 			"label_key": "label_value",
 		},
 	}
+	expectedObjectMetadata := metav1.ObjectMeta{
+		Name:      "name",
+		Namespace: "namespace",
+		Annotations: map[string]string{
+			"annotation_key": "annotation_value",
+		},
+		Labels: map[string]string{
+			"app.kubernetes.io/managed-by": "opentelemetry-operator",
+			"label_key":                    "label_value",
+		},
+	}
 	replicas := int32(2)
 	runAsNonRoot := true
 	privileged := true
@@ -63,7 +74,7 @@ func TestTargetAllocator(t *testing.T) {
 				},
 			},
 			want: &v1alpha1.TargetAllocator{
-				ObjectMeta: objectMetadata,
+				ObjectMeta: expectedObjectMetadata,
 				Spec: v1alpha1.TargetAllocatorSpec{
 					GlobalConfig: v1beta1.AnyConfig{},
 				},
@@ -172,7 +183,7 @@ func TestTargetAllocator(t *testing.T) {
 				},
 			},
 			want: &v1alpha1.TargetAllocator{
-				ObjectMeta: objectMetadata,
+				ObjectMeta: expectedObjectMetadata,
 				Spec: v1alpha1.TargetAllocatorSpec{
 					OpenTelemetryCommonFields: v1beta1.OpenTelemetryCommonFields{
 						Replicas:     &replicas,