nordisk/knut

knut consolidation seam evaluation (jera / skidbladnir / draupnir / facett panels)

Seam audit against the constellation standard (workspace_nordisk/.nornir/consolidation-panels-maps-design.md): no app re-implements service/systemd, job execution, provisioning, pane hosting, or map drawing — there is ONE crate for each. This is the read-only evaluation for knut; each item states the gap and either the additive fix or the honest reason it is deferred (a working, often feature-gated, hot path — forcing it now would regress a green surface or pull an unrelated dep tree into knut).

1. jobs / provisioning (jera → draupnir)

1.1 knut-pipelines server feature = a bespoke bollard container manager — DEFER

crates/knut-pipelines/src/server.rs (SparkServer, feature server) drives the Spark-Connect + SDP container up/down through bollard 0.20 against podman's REST API directly (Cargo.toml:118). This is the exact concern the consolidation chain owns: app → jera (job) → draupnir (OCI backend). It is effectively a fourth independent bollard engine in the constellation (jera's BollardEngine, draupnir's backend-oci, nornir/src/viz/test_boot.rs, and this).

Target (when unblocked): SparkServer submits a container job to jera::jobs, and jera provisions via draupnir::container (the DraupnirContainerBootRunner + run_to_completion seam that landed 2026-07-12). knut would then drop its bollard dep entirely.

Why deferred, not forced now:

• The jera container consolidation is itself still gated — per bencher_agents_problems.md (2026-07-12 draupnir/jera responses) jera KEPT its BollardEngine and has NOT flipped its default off bollard; the repoint of jera run_container onto draupnir::run_to_completion is open jera/nornir work. Repointing knut onto jera before jera itself is consolidated would chase a moving seam.
• server is a working, feature-gated path (OFF by default — the default build never pulls bollard). It brings up a real Spark JVM and waits on a ready line; a rewrite is a genuine provisioning change that must be bench/-integration verified against a live podman, which the Loki bencher does not have. This is the same class as korp's deferred daemon adoption and draupnir's own deferred jera repoint.
• Adopting jera pulls jera + draupnir (+ their trees) into knut-pipelines for a feature that is a thin container up/down — the dependency cost wants the shared seam to settle first.

Filed for: the jera/draupnir owners to finish the bollard consolidation; then a follow-up knut pass repoints SparkServer and removes bollard.

1.2 UI stream/repaint threads — jera N/A (not tracked jobs)

knut-pipelines/src/gui.rs:677,740 and knut-popviz/src/main.rs:93 use std::thread::spawn, and web.rs:189 / knut-bifrost/src/flight.rs:336 use tokio::spawn. These are event-driven UI repaint pumps and a Flight server handler task — in-process, untracked, no durable ledger semantics. Same finding as ordning's seam eval: jera::jobs routing is not applicable to pure in-proc UI/stream threads. No change.

2. service / systemd (skidbladnir)

knut-pipelines/src/server.rs:325 start_podman_socket_unit auto-starts the rootless podman.socket systemd user unit over D-Bus (zbus StartUnit), and bin/knut-spark-server.rs is an up/stop/status/logs lifecycle CLI. This is external-unit lifecycle management (bring up podman's socket so the container API is reachable), not "run knut itself as a managed systemd service", which is what skidbladnir::service/Lifecycle standardises. The overlap is marginal: knut is not daemonising itself. No forced change; if knut ever ships its own long-running service (e.g. a hosted pipeline runner), it should declare a skidbladnir::ServiceSpec then — noted for that future.

3. facett panels — knut is ALREADY on the component-crate model (positive example)

Unlike korp/holger (welded egui, §1.2 of the constellation doc), knut already consumes shared facett component crates, so there is no duplication to remove:

• knut-popviz (feature gui) renders through facett-pop (Cargo.toml:58) — the progress-bar/pop visual components, cut over from a local copy.
• knut-pipelines (feature facett-adapter) maps its Spark/SDP ViewerState onto facett-pipeline's engine-agnostic PipelineModel via the PipelineAdapter trait (Cargo.toml:90), the facett types never leaking into knut's public API.

Remaining (plan-only — facett is off-limits to this repo): there is no facett-knut* panel + <guest>-embed adapter (constellation §2) that would let another app HOST knut's pipeline/pop viewer as a Panel tab (the reusable fn panel(endpoint) -> Box<dyn Panel> shape). knut consumes facett panes; it does not yet EXPORT one for embedding. Creating that adapter is facett-side work (new facett-knut* component crate + a knut-embed adapter linking a thin gRPC client) and is explicitly out of scope for the knut repo — captured here so the facett/panel owner can pick it up under the extraction order (dwarves → holger → korp → nornir → …knut).

4. map trait (facett-map) — N/A

knut has no map/geo surface. The selectable MapLayer trait (constellation §3) does not apply. No action.

Summary