Propagate annotations to target allocator deployment

[nelsih]

Component(s)

target allocator

What happened?

Description

We need annotations under the targetallocator Deployment resource, which is needed for downscaling of it through the py-kube-downscaler application.

Currently, it's not possible to add annotations in the target allocator deployment. The following options have not worked so far to add annotations in the Deployment:

• Adding annotations under the OpenTelemetryCollector resource (they are propagated in the Pod annotations, but not in the Deployment annotations of TargetAllocator).
• Using the TargetAllocator CRD through usage of podAnnotations or annotations under metadata (annotations get also attached to the pods, but not the Deployment itself).

Expected Result

Having Annotations under the metadata of the TargetAllocator Deployment.

Actual Result

Annotations are attached to the Pods of the TargetAllocator, but not on the Deployment.

Kubernetes Version

1.33

Operator version

v0.134.0

Collector version

v0.134.0

Environment information

Environment

OS: Linux

Additional context

No response

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[mikel-jason]

I can contribute to this, but I need guidance here. What would we want to do? I see options:

• Introduce deploymentAnnotations similar to podAnnotations. But when using OpenTelemetryCollector, params.OtelCol.Spec.PodAnnotations is passed from OTelCol to TA spec. So it should be added to the OTelCol resource, too. There, we don't only have deployments but also statefulsets or daemonsets. So it might be a lot for such a simple change.
• Introduce deploymentAnnotations as described above, but as "TA CRD-only" feature
• Do what is already in place for OTelCol workload resources and just put the OTelCol CR annotations. They are passed to the TA, so that would be easy!

Relevant code

How TA annotations are (not) set to the workload

opentelemetry-operator/internal/manifests/targetallocator/deployment.go

Lines 25 to 42 in 2584188

	annotations := Annotations(params.TargetAllocator, configMap, params.Config.AnnotationsFilter)
	return &appsv1.Deployment{
	ObjectMeta: metav1.ObjectMeta{
	Name: name,
	Namespace: params.TargetAllocator.Namespace,
	Labels: labels,
	},
	Spec: appsv1.DeploymentSpec{
	Replicas: params.TargetAllocator.Spec.Replicas,
	Selector: &metav1.LabelSelector{
	MatchLabels: manifestutils.TASelectorLabels(params.TargetAllocator, ComponentOpenTelemetryTargetAllocator),
	},
	Template: corev1.PodTemplateSpec{
	ObjectMeta: metav1.ObjectMeta{
	Labels: labels,
	Annotations: annotations,
	},

How TA annotations are generated

opentelemetry-operator/internal/manifests/targetallocator/annotations.go

Lines 18 to 40 in 2584188

	// Annotations returns the annotations for the TargetAllocator Pod.
	func Annotations(instance v1alpha1.TargetAllocator, configMap *v1.ConfigMap, filterAnnotations []string) map[string]string {
	// Make a copy of PodAnnotations to be safe
	annotations := make(map[string]string, len(instance.Spec.PodAnnotations))
	for key, value := range instance.Spec.PodAnnotations {
	annotations[key] = value
	}
	if instance.ObjectMeta.Annotations != nil {
	for k, v := range instance.ObjectMeta.Annotations {
	if !manifestutils.IsFilteredSet(k, filterAnnotations) {
	annotations[k] = v
	}
	}
	}
	if configMap != nil {
	cmHash := getConfigMapSHA(configMap)
	if cmHash != "" {
	annotations[configMapHashAnnotationKey] = getConfigMapSHA(configMap)
	}
	}
	return annotations
	}

How a TA resource is generated from an OTelCol CR

opentelemetry-operator/internal/manifests/collector/targetallocator.go

Lines 31 to 63 in 2584188

	return &v1alpha1.TargetAllocator{
	ObjectMeta: metav1.ObjectMeta{
	Name: params.OtelCol.Name,
	Namespace: params.OtelCol.Namespace,
	Annotations: params.OtelCol.Annotations,
	Labels: labels,
	},
	Spec: v1alpha1.TargetAllocatorSpec{
	NetworkPolicy: v1beta1.NetworkPolicy{
	Enabled: params.OtelCol.Spec.NetworkPolicy.Enabled,
	},
	OpenTelemetryCommonFields: v1beta1.OpenTelemetryCommonFields{
	Replicas: taSpec.Replicas,
	NodeSelector: taSpec.NodeSelector,
	Resources: taSpec.Resources,
	ServiceAccount: taSpec.ServiceAccount,
	Image: taSpec.Image,
	Affinity: taSpec.Affinity,
	SecurityContext: taSpec.SecurityContext,
	PodSecurityContext: taSpec.PodSecurityContext,
	TopologySpreadConstraints: taSpec.TopologySpreadConstraints,
	Tolerations: taSpec.Tolerations,
	Env: taSpec.Env,
	PodAnnotations: params.OtelCol.Spec.PodAnnotations,
	PodDisruptionBudget: taSpec.PodDisruptionBudget,
	},
	AllocationStrategy: taSpec.AllocationStrategy,
	FilterStrategy: taSpec.FilterStrategy,
	PrometheusCR: taSpec.PrometheusCR,
	Observability: taSpec.Observability,
	CollectorNotReadyGracePeriod: taSpec.CollectorNotReadyGracePeriod,
	},
	}, nil

How annotations are set for OTelCol workloads

opentelemetry-operator/internal/manifests/collector/deployment.go

Lines 20 to 36 in 2584188

	annotations, err := manifestutils.Annotations(params.OtelCol, params.Config.AnnotationsFilter)
	if err != nil {
	return nil, err
	}
	podAnnotations, err := manifestutils.PodAnnotations(params.OtelCol, params.Config.AnnotationsFilter)
	if err != nil {
	return nil, err
	}
	return &appsv1.Deployment{
	ObjectMeta: metav1.ObjectMeta{
	Name: name,
	Namespace: params.OtelCol.Namespace,
	Labels: labels,
	Annotations: annotations,
	},

opentelemetry-operator/internal/manifests/collector/daemonset.go

Lines 21 to 37 in 2584188

	annotations, err := manifestutils.Annotations(params.OtelCol, params.Config.AnnotationsFilter)
	if err != nil {
	return nil, err
	}
	podAnnotations, err := manifestutils.PodAnnotations(params.OtelCol, params.Config.AnnotationsFilter)
	if err != nil {
	return nil, err
	}
	return &appsv1.DaemonSet{
	ObjectMeta: metav1.ObjectMeta{
	Name: naming.Collector(params.OtelCol.Name),
	Namespace: params.OtelCol.Namespace,
	Labels: labels,
	Annotations: annotations,
	},

opentelemetry-operator/internal/manifests/collector/statefulset.go

Lines 21 to 42 in 2584188

	annotations, err := manifestutils.Annotations(params.OtelCol, params.Config.AnnotationsFilter)
	if err != nil {
	return nil, err
	}
	podAnnotations, err := manifestutils.PodAnnotations(params.OtelCol, params.Config.AnnotationsFilter)
	if err != nil {
	return nil, err
	}
	serviceName := params.OtelCol.Spec.ServiceName
	if serviceName == "" {
	serviceName = naming.HeadlessService(params.OtelCol.Name)
	}
	return &appsv1.StatefulSet{
	ObjectMeta: metav1.ObjectMeta{
	Name: name,
	Namespace: params.OtelCol.Namespace,
	Labels: labels,
	Annotations: annotations,
	},

[maxutlvl]

@mikel-jason according to this issue, labels and annotations defined in the Collector CR are properly propagated to the Collector deployment.
However, the same labels are not propagated to the TargetAllocator deployment. Since the TargetAllocator now has its own CRD in recent OpenTelemetry Operator releases, the most consistent approach would be to handle label and annotations propagation in the same way as it is done for the OTelCol CR.