pkg/manifests: Expose retention size settings for Platform Prometheus

Introduce a new "retentionSize" field under the prometheusK8s key
When neither retention nor retentionSize are defined, a default of 15d for time retention applies.
When "retentionSize" is defined and "retention" isn't, only size retention applies.
When "retentionSize" isn't defined and "retention" is, only time retention applies
When both time and size retention fields are defined, both apply.

Signed-off-by: Jayapriya Pai <[email protected]>

Author: slashpai

CHANGELOG.md

@@ -8,6 +8,7 @@
 - [#1350](https://github.com/openshift/cluster-monitoring-operator/pull/1350) Support label scrape limits in user-workload monitoring
 - [#1601](https://github.com/openshift/cluster-monitoring-operator/pull/1601) Expose the /federate endpoint of UWM Prometheus as a service
 - [#1617](https://github.com/openshift/cluster-monitoring-operator/pull/1617) Add Oauth2 setting to PrometheusK8s remoteWrite config
+- [#1579](https://github.com/openshift/cluster-monitoring-operator/pull/1579) Expose retention size settings for Platform Prometheus
 
 ## 4.10
 

pkg/manifests/config.go

@@ -171,6 +171,7 @@ type RemoteWriteSpec struct {
 type PrometheusK8sConfig struct {
 	LogLevel            string                               `json:"logLevel"`
 	Retention           string                               `json:"retention"`
+	RetentionSize       string                               `json:"retentionSize"`
 	NodeSelector        map[string]string                    `json:"nodeSelector"`
 	Tolerations         []v1.Toleration                      `json:"tolerations"`
 	Resources           *v1.ResourceRequirements             `json:"resources"`
@@ -339,7 +340,7 @@ func (c *Config) applyDefaults() {
 	if c.ClusterMonitoringConfiguration.PrometheusK8sConfig == nil {
 		c.ClusterMonitoringConfiguration.PrometheusK8sConfig = &PrometheusK8sConfig{}
 	}
-	if c.ClusterMonitoringConfiguration.PrometheusK8sConfig.Retention == "" {
+	if c.ClusterMonitoringConfiguration.PrometheusK8sConfig.Retention == "" && c.ClusterMonitoringConfiguration.PrometheusK8sConfig.RetentionSize == "" {
 		c.ClusterMonitoringConfiguration.PrometheusK8sConfig.Retention = DefaultRetentionValue
 	}
 	if c.ClusterMonitoringConfiguration.AlertmanagerMainConfig == nil {

pkg/manifests/manifests.go

@@ -1442,6 +1442,10 @@ func (f *Factory) PrometheusK8s(grpcTLS *v1.Secret, trustedCABundleCM *v1.Config
 		p.Spec.Retention = f.config.ClusterMonitoringConfiguration.PrometheusK8sConfig.Retention
 	}
 
+	if f.config.ClusterMonitoringConfiguration.PrometheusK8sConfig.RetentionSize != "" {
+		p.Spec.RetentionSize = f.config.ClusterMonitoringConfiguration.PrometheusK8sConfig.RetentionSize
+	}
+
 	p.Spec.Image = &f.config.Images.Prometheus
 
 	if f.consoleConfig != nil && f.consoleConfig.Status.ConsoleURL != "" {

pkg/manifests/manifests_test.go

@@ -1557,6 +1557,74 @@ func TestPrometheusQueryLogFileConfig(t *testing.T) {
 	}
 }
 
+func TestPrometheusRetentionConfigs(t *testing.T) {
+	for _, tc := range []struct {
+		name                  string
+		retention             string
+		retentionSize         string
+		expectedRetention     string
+		expectedRetentionSize string
+	}{
+		{
+			name:                  "both retention and retentionSize defined",
+			retention:             "30d",
+			retentionSize:         "15GiB",
+			expectedRetention:     "30d",
+			expectedRetentionSize: "15GiB",
+		},
+		{
+			name:                  "only retention defined",
+			retention:             "45d",
+			expectedRetention:     "45d",
+			expectedRetentionSize: "",
+		},
+		{
+			name:                  "only retentionSize defined",
+			retentionSize:         "25GB",
+			expectedRetention:     "",
+			expectedRetentionSize: "25GB",
+		},
+		{
+			name:                  "both retention and retentionSize empty",
+			expectedRetention:     "15d",
+			expectedRetentionSize: "",
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			c := NewDefaultConfig()
+			c.ClusterMonitoringConfiguration.PrometheusK8sConfig.Retention = tc.retention
+			c.ClusterMonitoringConfiguration.PrometheusK8sConfig.RetentionSize = tc.retentionSize
+
+			f := NewFactory("openshift-monitoring", "openshift-user-workload-monitoring", c, defaultInfrastructureReader(), &fakeProxyReader{}, NewAssets(assetsPath), &APIServerConfig{}, &configv1.Console{})
+
+			p, err := f.PrometheusK8s(
+				&v1.Secret{ObjectMeta: metav1.ObjectMeta{Name: "foo"}},
+				&v1.ConfigMap{ObjectMeta: metav1.ObjectMeta{Name: "foo"}},
+			)
+
+			if tc.retention == "" && tc.retentionSize == "" {
+				if p.Spec.Retention != "15d" && p.Spec.RetentionSize != "" {
+					t.Fatal("Default Retention is not configured correctly")
+				}
+				return
+			}
+
+			if p.Spec.Retention != tc.expectedRetention {
+				t.Fatal("Retention is not configured correctly")
+			}
+
+			if p.Spec.RetentionSize != tc.expectedRetentionSize {
+				t.Fatal("RetentionSize is not configured correctly")
+			}
+
+			if err != nil {
+				t.Fatalf("Unexpected error occured %v", err)
+				return
+			}
+		})
+	}
+}
+
 func TestPrometheusK8sAdditionalAlertManagerConfigsSecret(t *testing.T) {
 	testCases := []struct {
 		name           string