Add flag to compress the Prometheus ConfigMap

cmd/operator/deploy/crds/monitoring.googleapis.com_operatorconfigs.yaml

@@ -93,6 +93,16 @@ spec:
             type: object
             description: Features holds configuration for optional managed-collection features.
             properties:
+              config:
+                type: object
+                description: Settings for the collector configuration propagation.
+                properties:
+                  compression:
+                    type: string
+                    description: Compression enables compression of the config data propagated by the operator to collectors. It is recommended to use the gzip option when using a large number of ClusterPodMonitoring and/or PodMonitoring.
+                    enum:
+                    - none
+                    - gzip
               targetStatus:
                 type: object
                 description: Configuration of target status reporting.

doc/api.md

@@ -26,6 +26,7 @@ This Document documents the types introduced by the GMP CRDs to be consumed by u
 * [ClusterRules](#clusterrules)
 * [ClusterRulesList](#clusterruleslist)
 * [CollectionSpec](#collectionspec)
+* [ConfigSpec](#configspec)
 * [ExportFilters](#exportfilters)
 * [GlobalRules](#globalrules)
 * [GlobalRulesList](#globalruleslist)
@@ -190,6 +191,19 @@ CollectionSpec specifies how the operator configures collection of metric data.
 
 [Back to TOC](#table-of-contents)
 
+## ConfigSpec
+
+ConfigSpec holds configurations for the Prometheus configuration.
+
+
+<em>appears in: [OperatorFeatures](#operatorfeatures)</em>
+
+| Field | Description | Scheme | Required |
+| ----- | ----------- | ------ | -------- |
+| compression | Compression enables compression of the config data propagated by the operator to collectors. It is recommended to use the gzip option when using a large number of ClusterPodMonitoring and/or PodMonitoring. | CompressionType | false |
+
+[Back to TOC](#table-of-contents)
+
 ## ExportFilters
 
 ExportFilters provides mechanisms to filter the scraped data that's sent to GMP.
@@ -325,6 +339,7 @@ OperatorFeatures holds configuration for optional managed-collection features.
 | Field | Description | Scheme | Required |
 | ----- | ----------- | ------ | -------- |
 | targetStatus | Configuration of target status reporting. | [TargetStatusSpec](#targetstatusspec) | false |
+| config | Settings for the collector configuration propagation. | [ConfigSpec](#configspec) | false |
 
 [Back to TOC](#table-of-contents)
 

manifests/setup.yaml

@@ -929,6 +929,16 @@ spec:
             type: object
             description: Features holds configuration for optional managed-collection features.
             properties:
+              config:
+                type: object
+                description: Settings for the collector configuration propagation.
+                properties:
+                  compression:
+                    type: string
+                    description: Compression enables compression of the config data propagated by the operator to collectors. It is recommended to use the gzip option when using a large number of ClusterPodMonitoring and/or PodMonitoring.
+                    enum:
+                    - none
+                    - gzip
               targetStatus:
                 type: object
                 description: Configuration of target status reporting.

pkg/operator/apis/monitoring/v1/types.go

@@ -117,6 +117,16 @@ type CollectionSpec struct {
 type OperatorFeatures struct {
 	// Configuration of target status reporting.
 	TargetStatus TargetStatusSpec `json:"targetStatus,omitempty"`
+	// Settings for the collector configuration propagation.
+	Config ConfigSpec `json:"config,omitempty"`
+}
+
+// ConfigSpec holds configurations for the Prometheus configuration.
+type ConfigSpec struct {
+	// Compression enables compression of the config data propagated by the operator to collectors.
+	// It is recommended to use the gzip option when using a large number of ClusterPodMonitoring
+	// and/or PodMonitoring.
+	Compression CompressionType `json:"compression,omitempty"`
 }
 
 // TargetStatusSpec holds configuration for target status reporting.
@@ -128,6 +138,9 @@ type TargetStatusSpec struct {
 // +kubebuilder:validation:Enum=none;gzip
 type CompressionType string
 
+const CompressionNone CompressionType = "none"
+const CompressionGzip CompressionType = "gzip"
+
 // KubeletScraping allows enabling scraping of the Kubelets' metric endpoints.
 type KubeletScraping struct {
 	// The interval at which the metric endpoints are scraped.

pkg/operator/collection.go

@@ -15,6 +15,8 @@
 package operator
 
 import (
+	"bytes"
+	"compress/gzip"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -174,7 +176,7 @@ func (r *collectionReconciler) Reconcile(ctx context.Context, req reconcile.Requ
 		return reconcile.Result{}, fmt.Errorf("ensure collector daemon set: %w", err)
 	}
 
-	if err := r.ensureCollectorConfig(ctx, &config.Collection); err != nil {
+	if err := r.ensureCollectorConfig(ctx, &config.Collection, config.Features.Config.Compression); err != nil {
 		return reconcile.Result{}, fmt.Errorf("ensure collector config: %w", err)
 	}
 
@@ -255,7 +257,7 @@ func (r *collectionReconciler) ensureCollectorDaemonSet(ctx context.Context, spe
 		flags = append(flags, fmt.Sprintf("--export.credentials-file=%q", p))
 	}
 
-	if len(spec.Compression) > 0 && spec.Compression != "none" {
+	if len(spec.Compression) > 0 && spec.Compression != monitoringv1.CompressionNone {
 		flags = append(flags, fmt.Sprintf("--export.compression=%s", spec.Compression))
 	}
 
@@ -300,8 +302,20 @@ func resolveLabels(opts Options, externalLabels map[string]string) (projectID st
 	return
 }
 
+func gzipData(data []byte) ([]byte, error) {
+	var b bytes.Buffer
+	gz := gzip.NewWriter(&b)
+	if _, err := gz.Write(data); err != nil {
+		return nil, err
+	}
+	if err := gz.Close(); err != nil {
+		return nil, err
+	}
+	return b.Bytes(), nil
+}
+
 // ensureCollectorConfig generates the collector config and creates or updates it.
-func (r *collectionReconciler) ensureCollectorConfig(ctx context.Context, spec *monitoringv1.CollectionSpec) error {
+func (r *collectionReconciler) ensureCollectorConfig(ctx context.Context, spec *monitoringv1.CollectionSpec, compression monitoringv1.CompressionType) error {
 	cfg, err := r.makeCollectorConfig(ctx, spec)
 	if err != nil {
 		return fmt.Errorf("generate Prometheus config: %w", err)
@@ -316,9 +330,26 @@ func (r *collectionReconciler) ensureCollectorConfig(ctx context.Context, spec *
 			Namespace: r.opts.OperatorNamespace,
 			Name:      NameCollector,
 		},
-		Data: map[string]string{
+	}
+
+	// Thanos config-reloader detects gzip compression automatically, so no sync with
+	// config-reloaders is needed when switching between these.
+	switch compression {
+	case monitoringv1.CompressionGzip:
+		compressedCfg, err := gzipData(cfgEncoded)
+		if err != nil {
+			return fmt.Errorf("gzip Prometheus config: %w", err)
+		}
+
+		cm.BinaryData = map[string][]byte{
+			configFilename: compressedCfg,
+		}
+	case "", monitoringv1.CompressionNone:
+		cm.Data = map[string]string{
 			configFilename: string(cfgEncoded),
-		},
+		}
+	default:
+		return fmt.Errorf("unknown compression type: %q", compression)
 	}
 
 	if err := r.client.Update(ctx, cm); apierrors.IsNotFound(err) {