Fix the semantic meaning of etcd server within component statuses and metrics.

Instead of numerating all the etcd endpoints known by apiserver, we will
group them by purpose. `etcd-0` will be the default etcd, `etcd-1` will
be the first resource override, `etcd-2` will be the second override and
so on.

pkg/registry/core/componentstatus/validator.go

@@ -117,5 +117,5 @@ func (server *EtcdServer) DoServerCheck() (probe.Result, string, error) {
 	if err != nil {
 		return probe.Failure, "", err
 	}
-	return probe.Success, "", err
+	return probe.Success, "ok", err
 }

staging/src/k8s.io/apiserver/pkg/server/storage/storage_factory.go

@@ -291,28 +291,17 @@ func Configs(storageConfig storagebackend.Config) []storagebackend.Config {
 
 // Returns all storage configurations including those for group resource overrides
 func configs(storageConfig storagebackend.Config, grOverrides map[schema.GroupResource]groupResourceOverrides) []storagebackend.Config {
-	locations := sets.NewString()
-	configs := []storagebackend.Config{}
-	for _, loc := range storageConfig.Transport.ServerList {
-		// copy
-		newConfig := storageConfig
-		newConfig.Transport.ServerList = []string{loc}
-		configs = append(configs, newConfig)
-		locations.Insert(loc)
-	}
+	configs := []storagebackend.Config{storageConfig}
 
 	for _, override := range grOverrides {
-		for _, loc := range override.etcdLocation {
-			if locations.Has(loc) {
-				continue
-			}
-			// copy
-			newConfig := storageConfig
-			override.Apply(&newConfig, &StorageCodecConfig{})
-			newConfig.Transport.ServerList = []string{loc}
-			configs = append(configs, newConfig)
-			locations.Insert(loc)
+		if len(override.etcdLocation) == 0 {
+			continue
 		}
+		// copy
+		newConfig := storageConfig
+		override.Apply(&newConfig, &StorageCodecConfig{})
+		newConfig.Transport.ServerList = override.etcdLocation
+		configs = append(configs, newConfig)
 	}
 	return configs
 }

staging/src/k8s.io/apiserver/pkg/server/storage/storage_factory_test.go

@@ -191,33 +191,36 @@ func TestConfigs(t *testing.T) {
 	defaultEtcdLocations := []string{"http://127.0.0.1", "http://127.0.0.2"}
 
 	testCases := []struct {
-		resource    schema.GroupResource
+		resource    *schema.GroupResource
 		servers     []string
 		wantConfigs []storagebackend.Config
 	}{
 		{
 			wantConfigs: []storagebackend.Config{
-				{Transport: storagebackend.TransportConfig{ServerList: []string{"http://127.0.0.1"}}, Prefix: "/registry", Paging: true},
-				{Transport: storagebackend.TransportConfig{ServerList: []string{"http://127.0.0.2"}}, Prefix: "/registry", Paging: true},
+				{Transport: storagebackend.TransportConfig{ServerList: defaultEtcdLocations}, Prefix: "/registry", Paging: true},
 			},
 		},
 		{
-			resource: schema.GroupResource{Group: example.GroupName, Resource: "resource"},
+			resource: &schema.GroupResource{Group: example.GroupName, Resource: "resource"},
+			servers:  []string{},
+			wantConfigs: []storagebackend.Config{
+				{Transport: storagebackend.TransportConfig{ServerList: defaultEtcdLocations}, Prefix: "/registry", Paging: true},
+			},
+		},
+		{
+			resource: &schema.GroupResource{Group: example.GroupName, Resource: "resource"},
 			servers:  []string{"http://127.0.0.1:10000"},
 			wantConfigs: []storagebackend.Config{
-				{Transport: storagebackend.TransportConfig{ServerList: []string{"http://127.0.0.1"}}, Prefix: "/registry", Paging: true},
-				{Transport: storagebackend.TransportConfig{ServerList: []string{"http://127.0.0.2"}}, Prefix: "/registry", Paging: true},
+				{Transport: storagebackend.TransportConfig{ServerList: defaultEtcdLocations}, Prefix: "/registry", Paging: true},
 				{Transport: storagebackend.TransportConfig{ServerList: []string{"http://127.0.0.1:10000"}}, Prefix: "/registry", Paging: true},
 			},
 		},
 		{
-			resource: schema.GroupResource{Group: example.GroupName, Resource: "resource"},
+			resource: &schema.GroupResource{Group: example.GroupName, Resource: "resource"},
 			servers:  []string{"http://127.0.0.1:10000", "https://127.0.0.1", "http://127.0.0.2"},
 			wantConfigs: []storagebackend.Config{
-				{Transport: storagebackend.TransportConfig{ServerList: []string{"http://127.0.0.1"}}, Prefix: "/registry", Paging: true},
-				{Transport: storagebackend.TransportConfig{ServerList: []string{"http://127.0.0.2"}}, Prefix: "/registry", Paging: true},
-				{Transport: storagebackend.TransportConfig{ServerList: []string{"http://127.0.0.1:10000"}}, Prefix: "/registry", Paging: true},
-				{Transport: storagebackend.TransportConfig{ServerList: []string{"https://127.0.0.1"}}, Prefix: "/registry", Paging: true},
+				{Transport: storagebackend.TransportConfig{ServerList: defaultEtcdLocations}, Prefix: "/registry", Paging: true},
+				{Transport: storagebackend.TransportConfig{ServerList: []string{"http://127.0.0.1:10000", "https://127.0.0.1", "http://127.0.0.2"}}, Prefix: "/registry", Paging: true},
 			},
 		},
 	}
@@ -230,8 +233,8 @@ func TestConfigs(t *testing.T) {
 			},
 		}
 		storageFactory := NewDefaultStorageFactory(defaultConfig, "", codecs, NewDefaultResourceEncodingConfig(scheme), NewResourceConfig(), nil)
-		if len(test.servers) > 0 {
-			storageFactory.SetEtcdLocation(test.resource, test.servers)
+		if test.resource != nil {
+			storageFactory.SetEtcdLocation(*test.resource, test.servers)
 		}
 
 		got := storageFactory.Configs()

staging/src/k8s.io/apiserver/pkg/storage/etcd3/metrics/metrics.go

@@ -84,7 +84,7 @@ var (
 		},
 		[]string{"endpoint"},
 	)
-	storageSizeDescription   = compbasemetrics.NewDesc("apiserver_storage_size_bytes", "Size of the storage database file physically allocated in bytes.", []string{"server"}, nil, compbasemetrics.ALPHA, "")
+	storageSizeDescription   = compbasemetrics.NewDesc("apiserver_storage_size_bytes", "Size of the storage database file physically allocated in bytes.", []string{"cluster"}, nil, compbasemetrics.ALPHA, "")
 	storageMonitor           = &monitorCollector{}
 	etcdEventsReceivedCounts = compbasemetrics.NewCounterVec(
 		&compbasemetrics.CounterOpts{
@@ -274,21 +274,21 @@ func (c *monitorCollector) CollectWithStability(ch chan<- compbasemetrics.Metric
 	}
 
 	for i, m := range monitors {
-		server := fmt.Sprintf("etcd-%d", i)
+		cluster := fmt.Sprintf("etcd-%d", i)
 
-		klog.V(4).InfoS("Start collecting storage metrics", "server", server)
+		klog.V(4).InfoS("Start collecting storage metrics", "cluster", cluster)
 		ctx, cancel := context.WithTimeout(context.Background(), time.Second)
 		metrics, err := m.Monitor(ctx)
 		cancel()
 		m.Close()
 		if err != nil {
-			klog.InfoS("Failed to get storage metrics", "server", server, "err", err)
+			klog.InfoS("Failed to get storage metrics", "cluster", cluster, "err", err)
 			continue
 		}
 
-		metric, err := compbasemetrics.NewConstMetric(storageSizeDescription, compbasemetrics.GaugeValue, float64(metrics.Size), server)
+		metric, err := compbasemetrics.NewConstMetric(storageSizeDescription, compbasemetrics.GaugeValue, float64(metrics.Size), cluster)
 		if err != nil {
-			klog.ErrorS(err, "Failed to create metric", "server", server)
+			klog.ErrorS(err, "Failed to create metric", "cluster", cluster)
 		}
 		ch <- metric
 	}

test/instrumentation/documentation/documentation-list.yaml

@@ -3760,7 +3760,7 @@
   type: Custom
   stabilityLevel: ALPHA
   labels:
-  - server
+  - cluster
 - name: transformation_duration_seconds
   subsystem: storage
   namespace: apiserver

test/instrumentation/documentation/documentation.md

@@ -932,7 +932,7 @@ components using an HTTP scrape, and fetch the current metrics data in Prometheu
 <td class="metric_stability_level" data-stability="alpha">ALPHA</td>
 <td class="metric_type" data-type="custom">Custom</td>
 <td class="metric_description">Size of the storage database file physically allocated in bytes.</td>
-<td class="metric_labels_varying"><div class="metric_label">server</div></td>
+<td class="metric_labels_varying"><div class="metric_label">cluster</div></td>
 <td class="metric_labels_constant"></td>
 <td class="metric_deprecated_version"></td></tr>
 <tr class="metric"><td class="metric_name">apiserver_storage_transformation_duration_seconds</td>

test/integration/metrics/metrics_test.go

@@ -77,7 +77,9 @@ func TestAPIServerProcessMetrics(t *testing.T) {
 }
 
 func TestAPIServerStorageMetrics(t *testing.T) {
-	s := kubeapiservertesting.StartTestServerOrDie(t, nil, nil, framework.SharedEtcd())
+	config := framework.SharedEtcd()
+	config.Transport.ServerList = []string{config.Transport.ServerList[0], config.Transport.ServerList[0]}
+	s := kubeapiservertesting.StartTestServerOrDie(t, nil, nil, config)
 	defer s.TearDownFn()
 
 	metrics, err := scrapeMetrics(s)