activate

Activates a node started on standby, at a migration's cut-over: joins every context's lease group and every topic's, starting the subscriptions there (one that starts at the end of its stream starts where the stream ends now), the retries of the parked entries, the jobs and the snapshot maintenance, and then admits commands. It is the operator's act, recorded for the audit: by names who activated it and reason why, both logged with the time. A node not on standby is left as it is: the answer says when it was activated, if it ever was. An activation that fails stops the node and throws.