Owner decision 2026-11-11: /fleet/diagnostics "Faulted devices" counts DISTINCT
devices across the nodes of the selected node's cluster, Faulted state only.
- DriverHostActor: FaultedDevices = HostState.Faulted only (Stopped no longer
counted); new StoppedDevices + FaultedHostNames. Counting extracted to the
testable DiagnosticsFromHealth.
- DriverInstanceDiagnostics: StoppedDevices (default 0) and FaultedHostNames
(default null) are additive with defaults, so a pre-#786 sender's snapshot
still deserializes over Akka's default JSON serializer (pinned by a test).
- FleetDiagnosticsAggregation (pure): identity key = (driver-instance string
id, HostName), case-insensitive; a single-host driver / nameless pre-#786
count is combined by MAX across nodes, never summed. Cluster peers come from
enabled ClusterNode rows of the selected node's ClusterId.
- FleetDiagnostics.razor: tile fetches the cluster peers and shows the
distinct count + "n of m nodes answered"; per-driver table gains a Stopped
devices column.
Claude-Session: https://claude.ai/code/session_01GT67AD99zQQqpLCVm3p7xk
DriverInstanceDiagnostics.Name carries the string driver-instance id
(what /hosts, telemetry and the artifact key on) and DriverInstanceId
the DB row Guid; the wire record has no slot for the authored display
name. The write-cap test asserts entry order per slot pair instead of
completion order of two concurrent writes.
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
DriverHostActor wraps the health publisher it hands its children in a
ChildHealthLedger (last snapshot per driver id, forwarded to the real
publisher), so GetDiagnostics now answers with each child's row id,
authored name, last-published state, device counts (host statuses when
the driver probes hosts, else one device) and last-change time — instead
of Guid.Empty / "Spawned" / 0 / now. Entries are forgotten on StopChild
and operator Restart.
IFleetDiagnosticsClient gains its first consumer: the new
/fleet/diagnostics page (node selector + ?node= query, revision,
running-from-cache notice, per-driver table). FleetDiagnosticsClient
logs the degrade-to-empty path at Warning.
Review ref: 02/U1.
Refs #731
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty