diff --git a/generated/google/apis/monitoring_v3.rb b/generated/google/apis/monitoring_v3.rb
index 831d8564b..2d5bbd60d 100644
--- a/generated/google/apis/monitoring_v3.rb
+++ b/generated/google/apis/monitoring_v3.rb
@@ -29,7 +29,7 @@ module Google
     # @see https://cloud.google.com/monitoring/api/
     module MonitoringV3
       VERSION = 'V3'
-      REVISION = '20201116'
+      REVISION = '20201208'
 
       # View and manage your data across Google Cloud Platform services
       AUTH_CLOUD_PLATFORM = 'https://www.googleapis.com/auth/cloud-platform'
diff --git a/generated/google/apis/monitoring_v3/classes.rb b/generated/google/apis/monitoring_v3/classes.rb
index b9b58914f..01350d555 100644
--- a/generated/google/apis/monitoring_v3/classes.rb
+++ b/generated/google/apis/monitoring_v3/classes.rb
@@ -426,7 +426,8 @@ module Google
       end
       
       # Istio service scoped to a single Kubernetes cluster. Learn more at http://
-      # istio.io.
+      # istio.io. Clusters running OSS Istio will have their services ingested as this
+      # type.
       class ClusterIstio
         include Google::Apis::Core::Hashable
       
@@ -2088,7 +2089,8 @@ module Google
         end
       end
       
-      # Istio service scoped to an Istio mesh
+      # Istio service scoped to an Istio mesh. Anthos clusters running ASM < 1.6.8
+      # will have their services ingested as this type.
       class MeshIstio
         include Google::Apis::Core::Hashable
       
@@ -3235,7 +3237,8 @@ module Google
         attr_accessor :cloud_endpoints
       
         # Istio service scoped to a single Kubernetes cluster. Learn more at http://
-        # istio.io.
+        # istio.io. Clusters running OSS Istio will have their services ingested as this
+        # type.
         # Corresponds to the JSON property `clusterIstio`
         # @return [Google::Apis::MonitoringV3::ClusterIstio]
         attr_accessor :cluster_istio
@@ -3251,7 +3254,8 @@ module Google
         # @return [String]
         attr_accessor :display_name
       
-        # Istio service scoped to an Istio mesh
+        # Istio service scoped to an Istio mesh. Anthos clusters running ASM < 1.6.8
+        # will have their services ingested as this type.
         # Corresponds to the JSON property `meshIstio`
         # @return [Google::Apis::MonitoringV3::MeshIstio]
         attr_accessor :mesh_istio
diff --git a/generated/google/apis/monitoring_v3/synth.metadata b/generated/google/apis/monitoring_v3/synth.metadata
index ecce57b7e..7008e17b1 100644
--- a/generated/google/apis/monitoring_v3/synth.metadata
+++ b/generated/google/apis/monitoring_v3/synth.metadata
@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/google-api-ruby-client.git",
-        "sha": "9130303612a389b31944a2781cd7378460b09d84"
+        "sha": "bd2875d8c126ec19d1a37b9179f60def0bf24899"
       }
     }
   ]