Comment 4 for bug 1829388

I've attempted several things to force the GCE credentials into an error state. If an account is deleted, Google returns an error, but Juju continually retries:

machine-7: 15:47:23 INFO juju.worker.machiner "machine-7" started
machine-7: 15:47:23 ERROR juju.worker.dependency "machiner" manifold worker returned unexpected error: cannot update observed network config: cannot get network interfaces of "juju-eaa547-7": Get https://www.googleapis.com/compute/v1/projects/juju-qa-checking-broken-creds/aggregated/instances?alt=json&filter=name+eq+juju-eaa547-.%2A: oauth2: cannot fetch token: 400 Bad Request
Response: {
  "error": "invalid_grant",
  "error_description": "Not a valid email or user ID."
}