A GKE-deployed app uses the Cloud SQL proxy container and reports database connection failures. For a post-mortem, what should you do first?

The first step in a post-mortem for connection failures is to gather diagnostic information. Consulting logs in Stackdriver (now Cloud Logging) for both GKE and Cloud SQL provides crucial details about the nature of the failures, such as authentication errors, network issues, or database unavailability. Restarting the SQL instance or restoring a backup are actions taken after understanding the problem, not initial diagnostic steps. Validating the Cloud Build Editor role is incorrect because the Cloud SQL proxy requires roles like Cloud SQL Client or Cloud SQL Editor, not Cloud Build Editor, and this check would come after an initial log review if permission issues were suspected.