diff --git a/metrics/doc.go b/metrics/doc.go
new file mode 100644
index 0000000000..631bb5966c
--- /dev/null
+++ b/metrics/doc.go
@@ -0,0 +1,16 @@
+/*
+Copyright 2018 The Knative Authors
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package metrics provides Knative utilities for exporting metrics to Stackdriver
+// backend or Prometheus backend based on config-observability settings.
+package metrics
diff --git a/metrics/metricskey/constants.go b/metrics/metricskey/constants.go
new file mode 100644
index 0000000000..57d8338a38
--- /dev/null
+++ b/metrics/metricskey/constants.go
@@ -0,0 +1,62 @@
+/*
+Copyright 2018 The Knative Authors
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package metricskey
+
+const (
+	// ResourceTypeKnativeRevision is the Stackdriver resource type for Knative revision
+	ResourceTypeKnativeRevision = "knative_revision"
+
+	// LabelProject is the label for project (e.g. GCP GAIA ID, AWS project name)
+	LabelProject = "project"
+
+	// LabelLocation is the label for location (e.g. GCE zone, AWS region) where the service is deployed
+	LabelLocation = "location"
+
+	// LabelClusterName is the label for immutable name of the cluster
+	LabelClusterName = "cluster_name"
+
+	// LabelNamespaceName is the label for immutable name of the namespace that the service is deployed
+	LabelNamespaceName = "namespace_name"
+
+	// LabelServiceName is the label for the deployed service name
+	LabelServiceName = "service_name"
+
+	// LabelConfigurationName is the label for the configuration which created the monitored revision
+	LabelConfigurationName = "configuration_name"
+
+	// LabelRevisionName is the label for the monitored revision
+	LabelRevisionName = "revision_name"
+
+	// ValueUnknown is the default value if the field is unknown, e.g. project will be unknown if Knative
+	// is not running on GKE.
+	ValueUnknown = "unknown"
+)
+
+var (
+	// KnativeRevisionLabels stores the set of resource labels for resource type knative_revision
+	KnativeRevisionLabels = map[string]struct{}{
+		LabelProject:           struct{}{},
+		LabelLocation:          struct{}{},
+		LabelClusterName:       struct{}{},
+		LabelNamespaceName:     struct{}{},
+		LabelServiceName:       struct{}{},
+		LabelConfigurationName: struct{}{},
+		LabelRevisionName:      struct{}{},
+	}
+
+	// ResourceTypeToLabelsMap maps resource type to the set of resource labels
+	ResourceTypeToLabelsMap = map[string]map[string]struct{}{
+		ResourceTypeKnativeRevision: KnativeRevisionLabels,
+	}
+)