fixup! MON-3500: Enable sending exemplars over RW in UWM

Author: rexagod

Documentation/api.md

@@ -525,7 +525,7 @@ The `RemoteWriteSpec` resource defines the settings for remote write storage.
 | proxyUrl | string | Defines an optional proxy URL. |
 | queueConfig | *[monv1.QueueConfig](https://github.com/prometheus-operator/prometheus-operator/blob/v0.66.0/Documentation/api.md#queueconfig) | Allows tuning configuration for remote write queue parameters. |
 | remoteTimeout | string | Defines the timeout value for requests to the remote write endpoint. |
-| sendExemplars | *bool | Enables sending of exemplars over remote write. Note that the experimental \"exemplar-storage\" feature must be enabled using the `spec.enableFeature` option for exemplars to be scraped in the first place. Only supported for UWM configurations. |
+| sendExemplars | *bool | Enables sending of exemplars over remote write. Note when enabled, Prometheus is configured to store exemplars in memory with a maximum number of 100,000 exemplars. The setting is only effective for user-defined monitoring and has no effect for cluster monitoring. |
 | sigv4 | *monv1.Sigv4 | Defines AWS Signature Version 4 authentication settings. |
 | tlsConfig | *[monv1.SafeTLSConfig](https://github.com/prometheus-operator/prometheus-operator/blob/v0.66.0/Documentation/api.md#safetlsconfig) | Defines TLS authentication settings for the remote write endpoint. |
 | url | string | Defines the URL of the remote write endpoint to which samples will be sent. |

Documentation/openshiftdocs/modules/remotewritespec.adoc

@@ -41,7 +41,7 @@ link:prometheusrestrictedconfig.adoc[PrometheusRestrictedConfig]
 
 |remoteTimeout|string|Defines the timeout value for requests to the remote write endpoint.
 
-|sendExemplars|*bool|Enables sending of exemplars over remote write. Note that the experimental \"exemplar-storage\" feature must be enabled using the `spec.enableFeature` option for exemplars to be scraped in the first place. Only supported for UWM configurations.
+|sendExemplars|*bool|Enables sending of exemplars over remote write. Note when enabled, Prometheus is configured to store exemplars in memory with a maximum number of 100,000 exemplars. The setting is only effective for user-defined monitoring and has no effect for cluster monitoring.
 
 |sigv4|*monv1.Sigv4|Defines AWS Signature Version 4 authentication settings.
 

pkg/manifests/manifests.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"hash/fnv"
 	"io"
+	"k8s.io/utils/ptr"
 	"net"
 	"net/url"
 	"path/filepath"
@@ -49,7 +50,6 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/util/yaml"
 	auditv1 "k8s.io/apiserver/pkg/apis/audit/v1"
-	"k8s.io/klog/v2"
 	apiregistrationv1 "k8s.io/kube-aggregator/pkg/apis/apiregistration/v1"
 )
 
@@ -1459,14 +1459,6 @@ func (f *Factory) PrometheusK8s(grpcTLS *v1.Secret, trustedCABundleCM *v1.Config
 
 	if len(f.config.ClusterMonitoringConfiguration.PrometheusK8sConfig.RemoteWrite) > 0 {
 		p.Spec.RemoteWrite = addRemoteWriteConfigs(clusterID, p.Spec.RemoteWrite, f.config.ClusterMonitoringConfiguration.PrometheusK8sConfig.RemoteWrite...)
-
-		// Explicitly warn that we are ignoring the `SendExemplars` configuration for in-cluster scenarios.
-		for _, rws := range f.config.ClusterMonitoringConfiguration.PrometheusK8sConfig.RemoteWrite {
-			if rws.SendExemplars != nil && *rws.SendExemplars {
-				klog.Warningln("Enabling `SendExemplars` in the in-cluster Prometheus configuration has no affect, as it is only supported for UWM configurations.")
-				break
-			}
-		}
 	}
 
 	for _, rw := range p.Spec.RemoteWrite {
@@ -1775,7 +1767,7 @@ func (f *Factory) PrometheusUserWorkload(grpcTLS *v1.Secret, trustedCABundleCM *
 		// Since `SendExemplars` is experimental currently, we need to enable "exemplar-storage" explicitly to make sure
 		// CMO turns this on automatically in Prometheus if any *UWM* RemoteWrite[] enables this.
 		for _, rws := range f.config.UserWorkloadConfiguration.Prometheus.RemoteWrite {
-			if *rws.SendExemplars {
+			if ptr.Deref(rws.SendExemplars, false) {
 				p.Spec.EnableFeatures = append(p.Spec.EnableFeatures, EnableFeatureExemplarStorageString)
 				break
 			}

pkg/manifests/types.go

@@ -753,10 +753,10 @@ type RemoteWriteSpec struct {
 	QueueConfig *monv1.QueueConfig `json:"queueConfig,omitempty"`
 	// Defines the timeout value for requests to the remote write endpoint.
 	RemoteTimeout string `json:"remoteTimeout,omitempty"`
-	// Enables sending of exemplars over remote write. Note that the experimental
-	// "exemplar-storage" feature must be enabled using the `spec.enableFeature`
-	// option for exemplars to be scraped in the first place. Only supported for
-	// UWM configurations.
+	// Enables sending of exemplars over remote write. Note when enabled, Prometheus is
+	// configured to store exemplars in memory with a maximum number of 100,000 exemplars.
+	// The setting is only effective for user-defined monitoring and has no effect for
+	// cluster monitoring.
 	SendExemplars *bool `json:"sendExemplars,omitempty"`
 	// Defines AWS Signature Version 4 authentication settings.
 	Sigv4 *monv1.Sigv4 `json:"sigv4,omitempty"`