External (Cloud SQL) GCP database will not work until PAS 2.5

[matthewfischer]

Describe the bug
Due to the way GCP Cloud SQL presents its certificate, credhub will refuse to connect to it. Credhub added a setting for this in credhub 2.0.3 but PAS will not have the config option until probably 2.5

We need to recommend strongly against external DB for credhub when deploying on Google Cloud.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this. Unfortunately, the Pivotal Tracker project is private so you may be unable to view the contents of the story.

The labels on this github issue will be updated when the story is started.