diff --git a/src/TensorflowCpy/proto/tensorflow/core/protobuf/cluster.proto b/src/TensorflowCpy/proto/tensorflow/core/protobuf/cluster.proto
new file mode 100644
index 0000000..41a55e0
--- /dev/null
+++ b/src/TensorflowCpy/proto/tensorflow/core/protobuf/cluster.proto
@@ -0,0 +1,84 @@
+/* Copyright 2016 The TensorFlow Authors. All Rights Reserved.
+
+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.
+==============================================================================*/
+
+syntax = "proto3";
+
+package tensorflow;
+
+option cc_enable_arenas = true;
+option java_outer_classname = "ClusterProtos";
+option java_multiple_files = true;
+option java_package = "org.tensorflow.distruntime";
+option go_package = "github.com/tensorflow/tensorflow/tensorflow/go/core/protobuf/for_core_protos_go_proto";
+
+// This file contains protos to be used when defining a TensorFlow
+// cluster.
+//
+// EXAMPLES
+// --------
+//
+// 1. A single-process cluster, containing "/job:local/task:0".
+//
+//    Cluster:
+//      job { name: 'local' tasks { key: 0 value: 'localhost:2222' } }
+//
+//    Server:
+//      cluster { $CLUSTER } job_name: 'local' task_index: 0
+//
+// 2. A two-process cluster, containing "/job:local/task:{0,1}".
+//
+//    Cluster:
+//      job { name: 'local' tasks { key: 0 value: 'localhost:2222' }
+//                          tasks { key: 1 value: 'localhost:2223' } }
+//
+//    Servers:
+//      cluster { $CLUSTER } job_name: 'local' task_index: 0
+//      cluster { $CLUSTER } job_name: 'local' task_index: 1
+//
+// 3. A two-job cluster, containing "/job:worker/task:{0,1,2}" and
+//    "/job:ps/task:{0,1}".
+//
+//    Cluster:
+//      job { name: 'worker' tasks { key: 0 value: 'worker1:2222' }
+//                           tasks { key: 1 value: 'worker2:2222' }
+//                           tasks { key: 2 value: 'worker3:2222' } }
+//      job { name: 'ps'     tasks { key: 0 value: 'ps0:2222' }
+//                           tasks { key: 1 value: 'ps1:2222' } }
+//
+//    Servers:
+//      cluster { $CLUSTER } job_name: 'worker' task_index: 0
+//      cluster { $CLUSTER } job_name: 'worker' task_index: 1
+//      cluster { $CLUSTER } job_name: 'worker' task_index: 2
+//      cluster { $CLUSTER } job_name: 'ps'     task_index: 0
+//      cluster { $CLUSTER } job_name: 'ps'     task_index: 1
+
+// Defines a single job in a TensorFlow cluster.
+message JobDef {
+  // The name of this job.
+  string name = 1;
+
+  // Mapping from task ID to "hostname:port" string.
+  //
+  // If the `name` field contains "worker", and the `tasks` map contains a
+  // mapping from 7 to "example.org:2222", then the device prefix
+  // "/job:worker/task:7" will be assigned to "example.org:2222".
+  map<int32, string> tasks = 2;
+}
+
+// Defines a TensorFlow cluster as a set of jobs.
+message ClusterDef {
+  // The jobs that comprise the cluster.
+  repeated JobDef job = 1;
+}
diff --git a/src/TensorflowCpy/proto/tensorflow/core/protobuf/config.proto b/src/TensorflowCpy/proto/tensorflow/core/protobuf/config.proto
index 7e549b7..e437b51 100644
--- a/src/TensorflowCpy/proto/tensorflow/core/protobuf/config.proto
+++ b/src/TensorflowCpy/proto/tensorflow/core/protobuf/config.proto
@@ -5,6 +5,7 @@ package tensorflow;
 import "tensorflow/core/framework/cost_graph.proto";
 import "tensorflow/core/framework/graph.proto";
 import "tensorflow/core/framework/step_stats.proto";
+import "tensorflow/core/protobuf/cluster.proto";
 import "tensorflow/core/protobuf/coordination_config.proto";
 import "tensorflow/core/protobuf/debug.proto";
 import "tensorflow/core/protobuf/rewriter_config.proto";
@@ -529,6 +530,8 @@ message ConfigProto {
   // Options that apply when this session uses the distributed runtime.
   RPCOptions rpc_options = 13;
 
+  // Optional list of all workers to use in this session.
+  ClusterDef cluster_def = 14;
 
   // If true, any resources such as Variables used in the session will not be
   // shared with other sessions. However, when clusterspec propagation is