feat(observability): add vllm-fleet rule group for frank-archon

radiance exports vllm:* metrics (verified on the live endpoint), not
llamacpp:*: nothing in llm-fleet could ever see frank-archon. Add a
vllm-fleet group - 1 recording + 4 alert (queueing, prefix-cache
collapse, preemption, p95 time-to-first-token) keyed to vllm:*.

Split the observability seam so llm-fleet rules bind llamacpp:* and
vllm-fleet rules bind vllm:*, and neither may evaluate the other's
namespace. Drops the retired no-metrics-for-archon doctrine the seam
still asserted and the vacuous namespace grep.
This commit is contained in:
Frank
2026-10-20 19:28:20 -07:00
parent 5cc2b3c25a
commit eb4d9910cb
2 changed files with 146 additions and 46 deletions
+93 -9
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@@ -1,10 +1,15 @@
# Alerting and recording rules for the LLM fleet.
#
# One metric namespace: llamacpp:* — frank-zealot and frank-dragoon, both
# llama.cpp with /metrics (the family verified from /metrics on 2026-09-16
# and 2026-09-20). frank-archon LEFT the family 2026-10-05: FreeToken (the
# PR587 ROCm engine) has no /metrics endpoint, so its scrape job was
# deleted rather than left never-green.
# Two metric namespaces, because two runtime families are scraped:
#
# * llamacpp:* — frank-zealot (llama.cpp) and frank-dragoon (halogen, which
# re-exports the llama.cpp metric names). Verified from /metrics on
# 2026-09-16 / 2026-09-20.
# * vllm:* — frank-archon, the radiance engine on Dankserver since
# 2026-10-05. It exports vLLM-compatible names, a DIFFERENT namespace, so
# it is a separate scrape job in prometheus.yml and the rules below are a
# separate group. (The old claim that its scrape job was deleted is false:
# it re-joined the day it left the FreeToken engine and is `up` today.)
# (The netavark published-port quirk that forces the Dankclaw endpoints
# onto the gateway is same-host only.)
#
@@ -22,7 +27,8 @@
# cached by cached + prompt.
# * Speculative decoding: drafts and accepted tokens are both counters,
# so LlmSpecDecodeOff watches the pair.
# * No latency histograms exist, so there is no p95 alert.
# * No latency histograms in llama.cpp, so no p95 alert there; radiance's
# vllm:* namespace DOES export one, so the vllm-fleet group alerts on it.
#
# IMPORTANT: delivery. Since 2026-09-17 a firing alert reaches Frank on
# Signal: Prometheus pushes to Alertmanager (dankclaw/observability/quadlet/
@@ -112,6 +118,84 @@ groups:
description: >-
Prometheus cannot reach the LLM endpoint. frank-zealot and
frank-dragoon are root units on Dankclaw: `systemctl is-active
frank-zealot` / `frank-dragoon`. Both scraped endpoints export
the llamacpp:* family. (frank-archon left the scrape set
2026-10-05 — FreeToken exports no /metrics.)
frank-zealot` / `frank-dragoon` (both export llamacpp:* —
dragoon via halogen's llama.cpp-compatible names). frank-archon
is a radiance endpoint on Dankserver (`systemctl show
frank-archon` there) exporting the vllm:* family; the
`frank-.*` selector covers all three regardless of namespace.
# frank-archon (radiance) exports the vLLM-compatible namespace, NOT
# llamacpp:*. Every rule here is keyed to a series the exporter actually
# emits (verified from /metrics 2026-10-20: num_requests_waiting,
# gpu_prefix_cache_hit_rate, num_preemptions_total, prompt_tokens_total,
# time_to_first_token_seconds). The llamacpp rules above evaluate nothing for
# this job and these evaluate nothing for llama.cpp/halogen — two clean
# namespaces, each keyed only to what its runtime exports.
- name: vllm-fleet
interval: 30s
rules:
# p95 time-to-first-token, shared with the dashboard. When the endpoint
# is idle every bucket rate is zero, histogram_quantile yields NaN, and
# neither this nor the alert below can fire on an idle engine.
- record: job:vllm_ttft_p95:rate5m
expr: |
histogram_quantile(0.95, sum by (job, le)
(rate(vllm:time_to_first_token_seconds_bucket[5m])))
# Radiance exports a real queue-depth gauge (llama.cpp only shows the
# wall as requests_deferred). --max-num-seqs is small, so a sustained
# wait is either real load or this endpoint carrying the fleet alone.
- alert: VllmRequestsQueueing
expr: vllm:num_requests_waiting > 0
for: 10m
labels:
severity: warning
annotations:
summary: "{{ $labels.job }}: requests waiting for 10 minutes"
description: >-
The radiance scheduler has requests queued. Either the fleet is
genuinely busy or this endpoint is carrying it alone.
# Radiance reports prefix reuse directly as a hit-rate gauge — no
# counter division needed. The token-rate floor keeps an idle engine
# (hit rate 0 with no traffic) from firing.
- alert: VllmPrefixCacheCollapse
expr: >-
vllm:gpu_prefix_cache_hit_rate < 0.20
and rate(vllm:prompt_tokens_total[5m]) > 0.05
for: 15m
labels:
severity: info
annotations:
summary: "{{ $labels.job }}: prefix hit rate below 20 % for 15 minutes"
description: >-
Nearly every request prefilling from scratch. With several large
contexts in flight this is the capacity wall, not a routing fault.
# Preemption is the KV-thrash signature radiance reports that llama.cpp
# cannot: the engine evicts a running request to admit another. Any
# sustained rate means the KV cache cannot hold the concurrency in flight.
- alert: VllmPreempting
expr: rate(vllm:num_preemptions_total[5m]) > 0
for: 5m
labels:
severity: warning
annotations:
summary: "{{ $labels.job }}: engine preempting requests"
description: >-
The engine is evicting running requests to admit new ones — the KV
cache is undersized for the concurrency in flight.
# p95 first-token latency, kept HIGH on purpose: a large-prompt prefill
# legitimately spends many seconds before token 1, so this fires only on
# a wedged scheduler or a queue backed up behind one request.
- alert: VllmTtftSlow
expr: job:vllm_ttft_p95:rate5m > 120
for: 10m
labels:
severity: warning
annotations:
summary: "{{ $labels.job }}: p95 time-to-first-token over 120 s"
description: >-
First-token latency is pathological, not an honest big prefill.
Likely a wedged scheduler or one request stalling the queue.
+53 -37
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@@ -313,33 +313,33 @@ PAIRS
done
}
@test "prometheus scrapes every LLM endpoint that exports metrics" {
# The LLM endpoints are the services whose behaviour this fleet argues about
# most (KV pressure, prefix-cache reuse, queue depth). Both Dankclaw
# endpoints export the llamacpp:* family. frank-archon LEFT the set
# 2026-10-05: the FreeToken PR587 ROCm engine has NO /metrics endpoint —
# scraping it was a structural never-green (404), so the job was deleted
# rather than left vacuous (the Lucebox DS4.1 precedent, 2026-09-26).
# The two Dankclaw endpoints are HOST processes reached through
# host.containers.internal: this Prometheus is a bridge-networked
# container, and on this netavark host a container can only reach the
# host's LAN IP at a PUBLISHED port — a host-process bind like
# llama-server's 0.0.0.0:7770 is refused at 192.168.0.143:7770 while it
# answers at 169.254.1.2:7770 (why frank-zealot stayed red by construction
# for days until the 2026-09-20 /targets audit).
@test "prometheus scrapes every LLM endpoint, in its real metric namespace" {
# Every LLM endpoint that exports /metrics must have a scrape job. As of
# 2026-10-05 there are TWO runtime namespaces scraped:
# * llamacpp:* — frank-zealot (llama.cpp) and frank-dragoon (halogen,
# re-exporting the llama.cpp names), both root host processes on
# Dankclaw reached via host.containers.internal — this Prometheus is a
# bridge container and a host-process bind is refused at the LAN IP,
# which is why frank-zealot read red by construction for days.
# * vllm:* — frank-archon (radiance) on Dankserver, a different machine,
# so plain LAN routing reaches 192.168.0.235:7770. It RE-JOINED the
# scrape set with radiance; the old "job deleted, exports no /metrics"
# note belonged to the retired FreeToken engine and is false today, so
# this seam now asserts archon IS scraped (a bare `! grep` here was
# set -e-exempt and never enforced the opposite).
local cfg="$REPO_ROOT/shared/prometheus/prometheus.yml"
grep -q '"host.containers.internal:7771"' "$cfg" || { echo "frank-zealot not scraped"; return 1; }
grep -q '"host.containers.internal:7770"' "$cfg" || { echo "frank-dragoon not scraped"; return 1; }
! grep -q '"192.168.0.235:7770"' "$cfg"
grep -q '"host.containers.internal:7770,192.168.0.235:7770"' "$cfg" \
&& { echo "frank-archon folded into a Dankclaw gateway target"; return 1; }
for job in frank-zealot frank-dragoon; do
grep -q '"192.168.0.235:7770"' "$cfg" || { echo "frank-archon not scraped"; return 1; }
for job in frank-zealot frank-dragoon frank-archon; do
grep -q "job_name: \"$job\"" "$cfg" || { echo "no scrape job for $job"; return 1; }
done
! grep -q 'job_name: "frank-archon"' "$cfg"
# None of them is reached through a guarded vhost: Prometheus cannot solve
# an Anubis challenge, so a franksdank.cloud target is red by construction.
! grep -qE '^\s*-\s*"?https?://[^"]*franksdank' "$cfg"
# No LLM endpoint is reached through a guarded vhost: Prometheus cannot
# solve an Anubis challenge, so a franksdank.cloud target is red by
# construction.
grep -qE '^[[:space:]]*-[[:space:]]*"?https?://[^"]*franksdank' "$cfg" \
&& { echo "a scrape target points at a guarded vhost"; return 1; }
true
}
@test "grafana provisioning is declared in git and installed by the deployer" {
@@ -378,28 +378,44 @@ names = [r.get('alert') or r.get('record') for g in d['groups'] for r in g['rule
for want in ('job:llm_prefix_cache_reuse:rate5m',
'job:llm_spec_accept_length:rate5m',
'LlmRequestsQueueing', 'LlmPrefixCacheCollapse',
'LlmSpecDecodeOff', 'LlmEndpointDown'):
'LlmSpecDecodeOff', 'LlmEndpointDown',
'job:vllm_ttft_p95:rate5m', 'VllmRequestsQueueing',
'VllmPrefixCacheCollapse', 'VllmPreempting', 'VllmTtftSlow'):
assert want in names, want
# Every rule must be keyed to a series that actually exists. A rule naming a
# series nobody exports evaluates nothing forever and errors never — the
# failure this seam exists for. Since the 2026-09-26 cutover the only scraped
# LLM runtime is llama.cpp (frank-zealot, frank-dragoon); the vllm: family left
# with frank-medium's radiance runtime and must not survive in any expr.
# failure this seam exists for. Two runtimes are scraped in two namespaces:
# llama.cpp/halogen (llamacpp:*) for frank-zealot and frank-dragoon, and
# radiance (vllm:*) for frank-archon. Both families were read straight off the
# endpoints' /metrics; anything else is a guess.
exprs = [r.get('expr', '') for g in d['groups'] for r in g['rules']]
# llama.cpp families measured from /metrics on 2026-09-16 and 2026-09-20
# (frank-zealot, frank-dragoon). Anything else is a guess.
live = {'llamacpp:prompt_tokens_total', 'llamacpp:prompt_tokens_cached_total',
'llamacpp:requests_deferred', 'llamacpp:requests_processing',
'llamacpp:spec_decode_num_drafts_total',
'llamacpp:spec_decode_num_accepted_tokens_total',
'llamacpp:spec_decode_num_draft_tokens_total',
'llamacpp:tokens_predicted_total',
'llamacpp:predicted_tokens_seconds', 'llamacpp:prompt_tokens_seconds',
'llamacpp:n_decode_total', 'llamacpp:n_busy_slots_per_decode'}
live = {
# llama.cpp / halogen, measured from /metrics 2026-09-16 and 2026-09-20.
'llamacpp:prompt_tokens_total', 'llamacpp:prompt_tokens_cached_total',
'llamacpp:requests_deferred', 'llamacpp:requests_processing',
'llamacpp:spec_decode_num_drafts_total',
'llamacpp:spec_decode_num_accepted_tokens_total',
'llamacpp:spec_decode_num_draft_tokens_total',
'llamacpp:tokens_predicted_total',
'llamacpp:predicted_tokens_seconds', 'llamacpp:prompt_tokens_seconds',
'llamacpp:n_decode_total', 'llamacpp:n_busy_slots_per_decode',
# radiance (frank-archon), measured from /metrics 2026-10-20.
'vllm:num_requests_waiting', 'vllm:gpu_prefix_cache_hit_rate',
'vllm:num_preemptions_total', 'vllm:prompt_tokens_total',
'vllm:time_to_first_token_seconds_bucket',
}
used = {m for e in exprs
for m in re.findall(r'(?:llamacpp|vllm):[a-z_0-9]+', e)}
assert used <= live, used - live
assert not any(':vllm' in e for e in exprs), 'vllm: series in rules but no vllm endpoint is scraped'
# The two namespaces must not bleed across groups: a llamacpp: selector
# evaluates nothing for the radiance job and vice versa, so each group may
# reference only its own family.
per = {g['name']: {m.split(':')[0] for r in g['rules']
for m in re.findall(r'(?:llamacpp|vllm):[a-z_0-9]+', r.get('expr', ''))}
for g in d['groups']}
for name, fams in per.items():
allowed = {'llamacpp'} if name == 'llm-fleet' else {'vllm'}
assert fams <= allowed, (name, fams)
print('rules ok:', len(names))
"
# A rule file that nothing loads evaluates nothing, and Prometheus reports