Add cluster config metrics in metrics-v3 (#19507)

endpoint: /minio/metrics/v3/cluster/config
metrics:
- write_quorum
- rrs_parity
- standard_parity

cmd/metrics-v3-cluster-config.go

@@ -0,0 +1,46 @@
+// Copyright (c) 2015-2024 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package cmd
+
+import "context"
+
+const (
+	configRRSParity      = "rrs_parity"
+	configStandardParity = "standard_parity"
+)
+
+var (
+	configRRSParityMD = NewGaugeMD(configRRSParity,
+		"Reduced redundancy storage class parity")
+	configStandardParityMD = NewGaugeMD(configStandardParity,
+		"Standard storage class parity")
+)
+
+// loadClusterConfigMetrics - `MetricsLoaderFn` for cluster config
+// such as standard and RRS parity.
+func loadClusterConfigMetrics(ctx context.Context, m MetricValues, c *metricsCache) error {
+	clusterDriveMetrics, err := c.clusterDriveMetrics.Get()
+	if err != nil {
+		metricsLogIf(ctx, err)
+	} else {
+		m.Set(configStandardParity, float64(clusterDriveMetrics.storageInfo.Backend.StandardSCParity))
+		m.Set(configRRSParity, float64(clusterDriveMetrics.storageInfo.Backend.RRSCParity))
+	}
+
+	return nil
+}

cmd/metrics-v3.go

@@ -52,6 +52,7 @@ const (
 	clusterUsageBucketsCollectorPath collectorPath = "/cluster/usage/buckets"
 	clusterErasureSetCollectorPath   collectorPath = "/cluster/erasure-set"
 	clusterIAMCollectorPath          collectorPath = "/cluster/iam"
+	clusterConfigCollectorPath       collectorPath = "/cluster/config"
 
 	auditCollectorPath         collectorPath = "/audit"
 	loggerWebhookCollectorPath collectorPath = "/logger/webhook"
@@ -342,6 +343,14 @@ func newMetricGroups(r *prometheus.Registry) *metricsV3Collection {
 		loadClusterReplicationMetrics,
 	)
 
+	clusterConfigMG := NewMetricsGroup(clusterConfigCollectorPath,
+		[]MetricDescriptor{
+			configRRSParityMD,
+			configStandardParityMD,
+		},
+		loadClusterConfigMetrics,
+	)
+
 	loggerWebhookMG := NewMetricsGroup(loggerWebhookCollectorPath,
 		[]MetricDescriptor{
 			webhookFailedMessagesMD,
@@ -378,6 +387,7 @@ func newMetricGroups(r *prometheus.Registry) *metricsV3Collection {
 		clusterNotificationMG,
 		clusterIAMMG,
 		clusterReplicationMG,
+		clusterConfigMG,
 
 		auditMG,
 		loggerWebhookMG,

docs/metrics/v3.md

@@ -261,6 +261,13 @@ The standard metrics group for GoCollector is not shown below.
 | `minio_cluster_health_capacity_usable_total_bytes` | `gauge` | Total cluster usable storage capacity in bytes |        |
 | `minio_cluster_health_capacity_usable_free_bytes`  | `gauge` | Total cluster usable storage free in bytes     |        |
 
+### `/cluster/config`
+
+| Name                                   | Type    | Help                                           | Labels |
+|----------------------------------------|---------|------------------------------------------------|--------|
+| `minio_cluster_config_rrs_parity`      | `gauge` | Reduced redundancy storage class parity        |        |
+| `minio_cluster_config_standard_parity` | `gauge` | Standard storage class parity                  |        |
+
 ### `/cluster/usage/objects`
 
 | Name                                                     | Type    | Help                                                           | Labels  |

internal/cachevalue/cache.go

@@ -92,7 +92,7 @@ func (t *Cache[T]) InitOnce(ttl time.Duration, opts Opts, update func(ctx contex
 // GetWithCtx will return a cached value or fetch a new one.
 // passes a caller context, if caller context cancels nothing
 // is cached.
-// Tf the Update function returns an error the value is forwarded as is and not cached.
+// If the Update function returns an error the value is forwarded as is and not cached.
 func (t *Cache[T]) GetWithCtx(ctx context.Context) (T, error) {
 	v := t.val.Load()
 	ttl := t.ttl