A new revision starts with zero traffic, on purpose.
Old revisions never disappear on their own — that's what makes rollback instant.
Deploy--no-traffic + a canary tag
Shift 10%Real traffic, watch metrics
Promote100% once healthy
Rollback?Reassign to old revision — no redeploy
Cloud Run functions is the current name for Cloud Functions 2nd gen — same revision/traffic model, no relearning needed. Eventarc routes CloudEvents-formatted events (storage, Pub/Sub, audit logs) to any target, decoupled from the source.