The forward upgrade to 26.7.3 was zero downtime across 87 samples, and since databasechangelog stayed at 210 the rollback to 26.7.0 also succeeded, which narrows D-2's conclusion: rolling back fails when the schema moved, not because of the version number. The row count is the check.
Role changes never reach the upstream through request repetition; the session is a snapshot taken at login and only a new session picks up the new claim. Auditing the docs also surfaced that Prometheus scrapes only keycloak, kubelet, node-exporter and itself, so the B-layer experiments have no metrics to screenshot rather than missing screenshots.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Five simultaneous refreshes with one token return a single 200, and that winner's new token is already dead. Reuse detection removes the client session while the user session stays, which is why the other responses read Session doesn't have required client rather than a reuse error.
Comparing policies shows rotation off passes all five and keeps the session, while raising refreshTokenMaxReuse to one still destroys it. Since no retry can recover a removed client session, Q2's own criterion resolves to a lock, and a database row lock is the natural place because its lifetime is tied to the connection.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
