How to get gcloud auth activate-service-account persist

I asked the GCloud devs and they mention a known bug where service accounts don't show up unless the environment variable CLOUDSDK_PYTHON_SITEPACKAGES is set.

Hopefully this will be fixed soon, but in the meantime, when you log in again, can you try running

export CLOUDSDK_PYTHON_SITEPACKAGES=1

and seeing if it then works?

You can run

gcloud auth list

to see what accounts there are credentials for; it should list your service account.