Generate and configure Prometheus client certs

When TLS and metricStorage are enabled, generate client certificate for
Prometheus. This will later be used by Prometheus to access metric
exporters which require client certificates.

jira: https://redhat.atlassian.net/browse/OSPRH-33208
Depends-On: openstack-k8s-operators/telemetry-operator#976
Generated-By: Claude-Code claude-opus-4-6

Author: vyzigold

internal/openstack/telemetry.go

@@ -4,7 +4,10 @@ import (
 	"context"
 	"fmt"
 
+	certmgrv1 "github.com/cert-manager/cert-manager/pkg/apis/certmanager/v1"
+	"github.com/openstack-k8s-operators/lib-common/modules/certmanager"
 	"github.com/openstack-k8s-operators/lib-common/modules/common"
+	"github.com/openstack-k8s-operators/lib-common/modules/common/clusterdns"
 	"github.com/openstack-k8s-operators/lib-common/modules/common/condition"
 	"github.com/openstack-k8s-operators/lib-common/modules/common/helper"
 	"github.com/openstack-k8s-operators/lib-common/modules/common/service"
@@ -29,6 +32,7 @@ const (
 
 // ReconcileTelemetry puts telemetry resources to required state
 func ReconcileTelemetry(ctx context.Context, instance *corev1beta1.OpenStackControlPlane, version *corev1beta1.OpenStackVersion, helper *helper.Helper) (ctrl.Result, error) {
+	Log := helper.GetLogger()
 	telemetry := &telemetryv1.Telemetry{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      telemetryName,
@@ -273,6 +277,7 @@ func ReconcileTelemetry(ctx context.Context, instance *corev1beta1.OpenStackCont
 		instance.Spec.Telemetry.Template.Autoscaling.Aodh.TLS = telemetry.Spec.Autoscaling.Aodh.TLS
 		instance.Spec.Telemetry.Template.MetricStorage.PrometheusTLS = telemetry.Spec.MetricStorage.PrometheusTLS
 		instance.Spec.Telemetry.Template.MetricStorage.AlertmanagerTLS = telemetry.Spec.MetricStorage.AlertmanagerTLS
+		instance.Spec.Telemetry.Template.MetricStorage.PrometheusClientCertSecret = telemetry.Spec.MetricStorage.PrometheusClientCertSecret
 		instance.Spec.Telemetry.Template.Ceilometer.TLS = telemetry.Spec.Ceilometer.TLS
 		instance.Spec.Telemetry.Template.Ceilometer.MysqldExporterTLS = telemetry.Spec.Ceilometer.MysqldExporterTLS
 		instance.Spec.Telemetry.Template.Ceilometer.KSMTLS = telemetry.Spec.Ceilometer.KSMTLS
@@ -442,6 +447,47 @@ func ReconcileTelemetry(ctx context.Context, instance *corev1beta1.OpenStackCont
 		// update TLS settings with cert secret
 		instance.Spec.Telemetry.Template.MetricStorage.PrometheusTLS.SecretName = prometheusEndpointDetails.GetEndptCertSecret(service.EndpointInternal)
 
+		// Generate Prometheus client certificate for scraping metrics from TLS-enabled endpoints
+		if instance.Spec.TLS.PodLevel.Enabled {
+			if promSvc, ok := prometheusEndpointDetails.EndpointDetails[service.EndpointInternal]; ok {
+				Log.Info("Reconciling Prometheus client certificate", telemetryNamespaceLabel, instance.Namespace)
+				clusterDomain := clusterdns.GetDNSClusterDomain()
+				certRequest := certmanager.CertificateRequest{
+					IssuerName: instance.GetInternalIssuer(),
+					CertName:   fmt.Sprintf("%s-client", promSvc.Name),
+					Hostnames: []string{
+						fmt.Sprintf("*.%s.svc", instance.Namespace),
+						fmt.Sprintf("*.%s.svc.%s", instance.Namespace, clusterDomain),
+					},
+					Usages: []certmgrv1.KeyUsage{
+						certmgrv1.UsageKeyEncipherment,
+						certmgrv1.UsageDigitalSignature,
+						certmgrv1.UsageClientAuth,
+					},
+					Labels: map[string]string{ServiceCertSelector: ""},
+				}
+				if instance.Spec.TLS.PodLevel.Internal.Cert.Duration != nil {
+					certRequest.Duration = &instance.Spec.TLS.PodLevel.Internal.Cert.Duration.Duration
+				}
+				if instance.Spec.TLS.PodLevel.Internal.Cert.RenewBefore != nil {
+					certRequest.RenewBefore = &instance.Spec.TLS.PodLevel.Internal.Cert.RenewBefore.Duration
+				}
+				certSecret, ctrlResult, err := certmanager.EnsureCert(
+					ctx,
+					helper,
+					certRequest,
+					nil)
+				if err != nil {
+					return ctrlResult, err
+				} else if (ctrlResult != ctrl.Result{}) {
+					return ctrlResult, nil
+				}
+				instance.Spec.Telemetry.Template.MetricStorage.PrometheusClientCertSecret.SecretName = &certSecret.Name
+			} else {
+				Log.Info("Prometheus internal endpoint not found, skipping client certificate generation", telemetryNamespaceLabel, instance.Namespace)
+			}
+		}
+
 		// EnsureEndpoint for alertmanager
 		// NOTE: We don't manage the alertmanager service, it's managed by COO, we just annotate it
 		alertmanagerEndpointDetails, ctrlResult, err := EnsureEndpointConfig(
@@ -539,7 +585,7 @@ func ReconcileTelemetry(ctx context.Context, instance *corev1beta1.OpenStackCont
 		instance.Spec.Telemetry.Template.Ceilometer.KSMTLS.SecretName = ksmEpDetails.GetEndptCertSecret(service.EndpointInternal)
 	}
 
-	helper.GetLogger().Info("Reconciling Telemetry", telemetryNamespaceLabel, instance.Namespace, telemetryNameLabel, telemetryName)
+	Log.Info("Reconciling Telemetry", telemetryNamespaceLabel, instance.Namespace, telemetryNameLabel, telemetryName)
 	op, err := controllerutil.CreateOrPatch(ctx, helper.GetClient(), telemetry, func() error {
 		instance.Spec.Telemetry.Template.TelemetrySpecBase.DeepCopyInto(&telemetry.Spec.TelemetrySpecBase)
 		instance.Spec.Telemetry.Template.Autoscaling.AutoscalingSpecBase.DeepCopyInto(&telemetry.Spec.Autoscaling.AutoscalingSpecBase)
@@ -639,11 +685,11 @@ func ReconcileTelemetry(ctx context.Context, instance *corev1beta1.OpenStackCont
 		return ctrl.Result{}, err
 	}
 	if op != controllerutil.OperationResultNone {
-		helper.GetLogger().Info(fmt.Sprintf("%s %s - %s", telemetryName, telemetry.Name, op))
+		Log.Info(fmt.Sprintf("%s %s - %s", telemetryName, telemetry.Name, op))
 	}
 
 	if telemetry.Status.ObservedGeneration == telemetry.Generation && telemetry.IsReady() {
-		helper.GetLogger().Info("Telemetry ready condition is true")
+		Log.Info("Telemetry ready condition is true")
 		instance.Status.ContainerImages.CeilometerCentralImage = version.Status.ContainerImages.CeilometerCentralImage
 		instance.Status.ContainerImages.CeilometerComputeImage = version.Status.ContainerImages.CeilometerComputeImage
 		instance.Status.ContainerImages.CeilometerIpmiImage = version.Status.ContainerImages.CeilometerIpmiImage