title: GCP OS Login creates user_domain account
body: <p>I am testing OS login and created a instance with metadata "enable-oslogin=TRUE". I then added OS Login role to my account(user@mydomainname.com). When I tried:</p>
  
  <pre><code>user@original_host$ gcloud compute ssh my_instance --project my_project --zone my_zone
  </code></pre>
  
  <p>GCP allowed me login, but as user user_mydomainname instead of my original account "user"</p>
  
  <p>When I tried:</p>
  
  <p><code>user@original_host$ ssh my_instance, it denied my login</code>.</p>
  
  <p>When I tried:</p>
  
  <pre><code>user@original_host$ ssh user_mydomainname@my_instance, it allowed me login, but as user_mydomainname of course.
  </code></pre>
  
  <p>I read a bunch of OS login documents from Google and could not figure out the reason. IN one doc: <a href="https://cloud.google.com/compute/docs/instances/managing-instance-access#login_messages" rel="nofollow noreferrer">https://cloud.google.com/compute/docs/instances/managing-instance-access#login_messages</a></p>
  
  <p>At the <code>Expected login behaviors</code> section, it reads "If a username is not set by a G Suite administrator, OS Login generates a default Linux username by combining the username and domain from the email associated with the user's Google profile. This naming convention ensures uniqueness. For example, if the user email associated with the Google profile is user@example.com, then their generated username is user_example_com."</p>
  
  <p>This looks like what I am getting, but I had set OS login role to my account.</p>
  
  <p>I was expecting with the OS login role setup, I could login to the instance as my original account: user</p>
  
  <p>Did I miss anything here or this is indeed the expected behavior? Is is possible to get my account "user" to use OS Login w/o getting user_mydomainname?</p>
  
  <p>Thanks,
  Philip</p>