Every deploy creates a new revision with zero traffic.
Traffic assignment is a separate, explicit step — the mechanism that makes canary and instant rollback both possible.
Deploy v13--no-traffic, tagged canary
Shift 10%Real canary, not all-or-nothing
Promote to 100%Once confidence established
RollbackInstant traffic reassignment — no redeploy
--min-instances=1 is deliberate, not a default — it trades a small always-on cost for eliminating a customer-visible cold start on the first request after idle time.