Upgrades #

Upgrade a cluster by changing spec.version to an adjacent supported version (same minor patch bump, or the next minor). The admission webhook rejects non-adjacent jumps with UpgradePathInvalid.

The operator runs an ordered state machine, visible in status.upgrade.phase:

PreflightChecks -> SchemaMigrating -> RollingFrontend -> RollingHistory ->
RollingMatching -> RollingInternalFrontend? -> RollingWorker -> PostUpgrade -> Complete

• Schema migrations run before any service is rolled.
• Services adopt the new image one role at a time; each phase advances only once the previous role is fully rolled out.
• status.upgrade.rollbackable is true until schema migration begins.

status.version reflects the running version and only advances to the target once the rollout completes.