I installed the plugin.

Copied the service account to a location that Jenkins can 'see' (/var/jenkins_home)

Set env vars in the helm chart and in the the Jenkins UI.

GOOGLE_APPLICATION_CREDENTIALS /var/jenkins_home/jenkins-test-project.json

But when I try to access GCP secret manager credentials in the Jenkins UI, I get the following error message:

Could not retrieve the credentials from GCP Secrets Manager java.io.IOException: The Application Default Credentials are not available. They are available if running in Google Compute Engine. Otherwise, the environment variable GOOGLE_APPLICATION_CREDENTIALS must be defined pointing to a file defining the credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information.

etc...

Any ideas on how this is supposed to work on a system running K8S but not in GCP?