In order to install GCS software, you must sudo. The GCS install creates 2 files in the user's current working directory:
-rw-------. 1 root root 1615 Apr 21 15:27 deployment-key.json
-rw-r--r--. 1 root root 0 Apr 21 15:27 globus-connect-server.log
Then, during the globus-connect-server endpoint create step, which should be done as the user, it tries to read the deployment-key.json file which it cannot do. So I sudo'd and chmod'd it to be 644. Then went back and reran the command. it then tried to write to the globus-connect-server.log file. It couldn't do that either since it was 644. So I sudo'd and chmod'd it to 666.