Add option to select a different TPU zone in create_run_config

tensor2tensor/utils/trainer_lib.py

@@ -178,7 +178,8 @@ def create_run_config(model_name,
                       log_step_count_steps=100,
                       intra_op_parallelism_threads=0,
                       tpu_config_extra_kwargs=None,
-                      cloud_tpu_name=""):
+                      cloud_tpu_name="",
+                      cloud_tpu_zone=None):
   """Create RunConfig, TPUConfig, and Parallelism object."""
   session_config = create_session_config(
       log_device_placement=log_device_placement,
@@ -229,7 +230,7 @@ def create_run_config(model_name,
       # Update run_config to use cluster instead of master/evaluation_master
       # as we need the cluster spec to use Cloud Pods
       tpu_cluster_resolver = contrib.cluster_resolver().TPUClusterResolver(
-          cloud_tpu_name)
+          tpu=cloud_tpu_name, zone=cloud_tpu_zone)
       run_config_args["cluster"] = tpu_cluster_resolver
       del run_config_args["master"]
       del run_config_args["evaluation_master"]