Error running Radical on GCP

[aalothman]

Hello, I am having a trouble running radical on GCP. I reach the point on the tutorial where I start the radical run but I get this error always.
`aalothman@tutserver:~/autolfads/pbt_opt$ python2 pbt_script_multiVM.py

Traceback (most recent call last):

File "pbt_script_multiVM.py", line 25, in
helper = pbtHelper(bucket_name, data_path, run_path, name, nprocess_gpu)
File "/home/aalothma/autolfads/pbt_opt/pbt_helper_fn.py", line 19, in init
self.server_id = os.environ["HOSTNAME"]
File "/usr/lib/python2.7/UserDict.py", line 40, in getitem
raise KeyError(key)
KeyError: 'HOSTNAME'`

Things I have done:
1- checked that docker is installed correctly on clients
2- deleted client and server three times and created new one. I still get the same error each run.

Things to note:
I only have one client, as opposed to the recommended number in the tutorial.

I appreciate any help that can be provided.

Thank you so much.