Importing plugins.docker.models by path defines its tables a second time,
because the plugin manager loaded them as _steward_plugin_docker.models.
Inside the app that raises InvalidRequestError, not ImportError. The cadence
integration test hit it, and #5767's _swarm (used when a job is planned)
carried the same import. Both now go through maintenance.docker_models().
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
#5768 "A maintenance cadence: a group's updates and reboots, one host at a
time, on a schedule". A plan names an inventory group, a weekday and time
in a time zone, a window and a reboot policy (only when required by
default). At its slot a run takes the group's hosts in order and gives each
a #5767 maintenance job. The next host starts only when the last is back in
service: its agent is posting and, for a swarm node, the node is active and
every replicated service is at its replicas. A failure stops the run, and
no host is started once the window has passed. A host's latest failure
shows as host_agent/<host>/maintenance_failed, for an ordinary alert rule.
The page is Hosts → Maintenance.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>