On 2026-10-18 an update on VDNT-Docker02 restarted the Docker daemon six
seconds in, before the drain that came only with the reboot, and every
container on the node stopped. Docker's own packages restart the daemon from
their install scripts; needrestart's list-only mode doesn't stop that.
- The helper gains a `check` action (agent 1.24.0): a dry run of the update
for each package manager, whether Docker is among it, and the running
containers outside the swarm with their restart policies.
- A swarm node is drained before an update that upgrades Docker, else only
before a reboot, and at most once a job.
- After a drain the job settles 5 minutes before the update or reboot.
- Once the work is over, the containers that ran outside the swarm must be
seen running again within 10 minutes, or the job fails naming them.
- An older agent gets no check and its job runs as before.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
#5834 "The host agent is always on, and the MCP sees a host's
maintenance", step 1 of milestone 520 "The MCP sees what Steward has
grown".
The host agent is a core system (operator, 2026-10-15: "it's very core
to the functionality of Steward as a whole and shouldn't be considered
something that can be toggled off"). ALWAYS_ON_PLUGINS in core settings
makes to_plugins_cfg report it enabled whatever its stored row says, so
it always loads and its MCP tools are always listed. Settings -> Plugins
shows it as "Built in: always on" with no switch, and a save keeps it
enabled. Its code and URLs stay under plugins/host_agent: every
installed agent posts to /plugins/host_agent/ingest.
Maintenance through the MCP:
- list_maintenance_plans: each plan's group, weekly slot, reboot policy,
next slot, and its latest run (hosts, how far it got, who it skipped
and why, how it ended).
- get_maintenance_job(host | job): a host's jobs, newest and running
first, or one job: state, packages updated, reboot, drained by, why it
failed, when its current state times out.
- run_maintenance(host, reboot="if_required" | "never"): admin, as the
host page's Update now; refuses a busy host or one with no helper;
audited "<user> via MCP".
- The overview names a host whose latest job in the last week failed or
timed out.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
MCP-5 of milestone 461 "MCP server: Steward as an LLM-inspectable,
LLM-operable hub". Contributed through each plugin's register_mcp_tools
hook, so they exist only while the plugin is enabled.
docker (viewer, read-only):
- list_containers: filter by host, status, compose project, or problem
(restarting, crash_looping, unhealthy, oom_killed, exited_nonzero);
problems sort first and each row names what is wrong.
- get_container: state, CPU/memory history across the raw/hourly seam,
lifecycle events. A unique part of a swarm task name is enough.
- list_swarm_services: replicas per node (agent-less placements as ghosts)
and the swarm's nodes.
- search_container_logs: text (% and _ literal), stream, range, context
lines, paging by a full-precision `before` cursor; over-long lines keep
both ends and say how much of the middle was cut.
- get_docker_disk_usage: bytes per host, reclaimable first.
- mcp_overview: failing containers and under-replicated swarm services
join get_overview.
host_agent: list_agents (reporting / stale / pending, version, OS), and an
overview finding for agents registered over 30 minutes ago that never
checked in.
Settings > Thresholds gains the TLS-expiry warn/crit days (were 14/3 in
code) and the crash-loop deaths-per-hour count (3), which get_overview
and the docker tools now read.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
bvandeusenandClaude Opus 5.5