Removes the six OTel packages (opentelemetry, _api, _exporter,
_phoenix, _oban, _bandit) and their 9 transitive deps. Tracing was
only wired for Phoenix/Bandit/Oban auto-instrumentation — PromEx
already covers the metrics we actually use on the status page +
Grafana. Also drops the OTEL_EXPORTER_OTLP_ENDPOINT env var and
its comment block from both deployment manifests.
Adds HorizontalPodAutoscaler resources for the three load-responsive
Deployments:
- prop (web): min 2, max 5, averageValue 800m CPU
- prop-grid-rs: min 1, max 4, averageValue 400m
- hrrr-point-rs: min 1, max 4, averageValue 400m
- prop-backfill is intentionally unmanaged (queue-driven, not CPU-bound)
The scale-up policy reacts in 30 s with up-to-2-pods or +100 % per
window; scale-down stabilises over 10 min so the hourly propagation
chain doesn't churn replicas right after the :05 cron.
Removes `spec.replicas` from the HPA-managed Deployments so Flux's
periodic reconcile stops fighting HPA's live scaling decisions.
Drops `podAntiAffinity` from prop, prop-grid-rs, and hrrr-point-rs
so HPA can actually reach its maxReplicas when one physical host has
capacity for two pods; the scheduler picks whatever fits.
Updates runbook + project memory to drop the `talos5` hostname —
Postgres is now addressed strictly by IP (10.0.15.30).
IemreFetchWorker now writes an empty stub observation when IEM returns
a permanent-failure status (404, 422), mirroring the existing {:ok, []}
path. The backfill cron's next tick sees the stub via
has_iemre_observation?/3, generates no job, and mark_status!/3 flips
the contact's iemre_status from :queued to :complete — draining the
51 contacts that have been stuck behind cancelled out-of-grid IEMRE
jobs.
Raise hot pod CPU limit 2 → 3 so BEAM gets 3 schedulers online.
Observed run queues of [2, 10, 0, 0, 0, 0] on the 2-scheduler
configuration during the :05 propagation chain, starving /live and
/health probe handlers and tripping intermittent liveness timeouts.
Per-pod IEM rate limiter was 700ms (~1.4 req/sec); four pods put the
fleet at ~5.7 req/sec, above the observed 429 threshold. Retry storm
(Req exponential backoff up to 32s) piled concurrent sleeps on top of
live workers and tripped Bandit's acceptor + Oban's leader heartbeat.
- Raise default interval to 1500ms (~2.7 req/sec fleet).
- Hot pod /live timeout 3s → 5s (acceptor stalls under retry sleeps).
- prop-backfill exec probe period 30s → 120s, timeout 15s → 30s; the
release CLI round-trips through distributed Erlang and 15s wasn't
enough under load, restart-looping every ~10 min.
Every prop pod restart was dumping a pair of ArgumentError stack
traces from grpcbox_channel / grpcbox_subchannel terminate/3:
:ets.select(:gproc, …)
* 1st argument: the table identifier does not refer to an
existing ETS table
This is a known grpcbox shutdown race: the OTLP/gRPC transport's
terminate callback tries to look itself up in gproc's ETS just
after gproc's supervisor has already torn the table down. Noisy,
not harmful — but one ArgumentError per restart × N pods adds up.
The OTLP/HTTP transport (port 4318 on the same otel-collector
Service) has no gproc/ETS channel machinery, so shutdown is
quiet. Spans are identical — our collector already accepts both.
- `config/runtime.exs`: default `otlp_protocol: :http_protobuf`,
with an `OTEL_EXPORTER_OTLP_PROTOCOL=grpc` escape hatch.
- `k8s/deployment.yaml`: point `OTEL_EXPORTER_OTLP_ENDPOINT` at
:4318 instead of :4317. The Rust workers stay on :4317 — their
native opentelemetry-otlp transport doesn't share the grpcbox
bug.
Investigated why all three prop pods were restart-looping every few
minutes (RESTARTS counts 7–11 in 99m). The trail:
20:53:33.058 [error] Postgrex.Protocol ("db_conn_10") disconnected:
client (:"Elixir.Microwaveprop.PromEx.Poller.5000") timed out
because it queued and checked out the connection for longer than
15000ms
PromEx's Oban queue-depth poller was scanning the oban_jobs table
every 5s and holding an Ecto connection past its checkout timeout.
That starved the rest of the pool, so /health's `SELECT 1` couldn't
acquire a connection inside the 3s liveness probe timeout, the
kubelet's failureThreshold=3 tripped, and SIGKILL landed on the
BEAM. Every replica cycled on the same cadence.
Two fixes:
1. Split /live (no DB) from /health (DB ping). Kubernetes livenessProbe
now points at /live so a saturated Ecto pool can never cascade into
SIGKILL. Readiness still hits /health so a genuine DB outage drains
the pod from Service endpoints gracefully.
2. Turn off the PromEx Oban plugin in prod via the same flag already
used in test. The queue-depth query isn't worth pod instability;
the oban_web dashboard surfaces the same information without
scanning the job table on a timer.
Locked both down with HealthController tests that verify /live never
touches the Repo (no sandbox owner, controller.live/2 called directly,
200 ok) and /health does (sanity query round-trips).
Set OTEL_EXPORTER_OTLP_ENDPOINT on the prop deployment to the cluster
Collector so Phoenix/Bandit/Oban spans export and link up with
downstream prop-grid-rs / prop-hrrr-point-rs traces in Tempo. Without
this the Elixir app fell back to traces_exporter :none and the Rust
worker spans had no parent, leaving the trace graph disconnected.
The stale comment referenced opentelemetry_ecto as the reason export
was off, but that package was never added to mix.exs (only
opentelemetry_phoenix / _bandit / _oban are listed), so the
span-flood concern no longer applies.
