Previous comments described llm_ttft_seconds / llm_itl_seconds /
llm_tokens_total as "streaming-only". That was wrong, and optimistic.
They are dead code. internal/proxy/llm_metrics.go defines
LLMMetricsCapture, which is the only thing that calls RecordTTFT /
RecordITL / RecordTokens — but NewLLMMetricsCapture() has zero call sites
anywhere in the repo, verified by grep. The exporter skips keys with no
samples, so those three series render as HELP-only stubs and can never be
graphed, streaming or not.
No behaviour change here; only the comments and the dashboard generator's
header are corrected so the next person does not build on a false
assumption. The gateway latency panels are left in place so the gap stays
visible — they populate unchanged once the capture wrapper is wired into
the streaming proxy path.
Series that DO work from the gateway, confirmed live with 3 series (one
per replica): queue_full_requests_total, warmup_requests_delayed_total,
vllm_prefix_cache_hit_tokens_total.
Both new ServiceMonitors sat permanently OutOfSync. Cause: `action: replace`
is the API server default for relabeling rules, so the live object carried it
while the manifests omitted it.
Rather than write out the default to paper over drift, removed the rules that
were never needed:
- vllm.yaml: the namespace/pod/service relabelings were redundant —
Kubernetes service discovery already supplies all three. Only `app` has to
be derived (TEI panels aggregate by it and SD does not promote arbitrary
pod labels). Kept that one, with an explicit action.
- api-gateway.yaml: the metricRelabelings block was a no-op — it mapped
__address__ onto instance, which is already the default. Removed. The
series inventory it was documenting moved up into the file header, which
is where it belonged anyway.
New Grafana dashboard (llm-observability) with 27 panels across 5 rows:
TTFT, inter-token latency, batching/scheduling, KV cache, throughput.
Both metric sources are shown side by side because they answer different
questions and neither is complete alone:
vLLM 0.11.0 (reasoning) — engine truth: kv_cache_usage_perc,
num_requests_running/waiting, num_preemptions_total, prefill vs
decode time, prefix cache, per-request histogram quantiles.
TEI 1.8.2 (embeddings, reranker) — te_batch_next_size, te_queue_size,
te_embed_duration, te_embed_queue_duration.
api-gateway — the ONLY per-request latency source covering Ollama
models (ornith:35b, qwen2.5:3b-instruct), which expose no metrics.
It is derived from the SSE byte stream, so it is streaming-only and
counts SSE chunks rather than true tokens. vLLM's own histograms are
authoritative for reasoning.
All 44 panel queries were executed against live Prometheus before commit —
all return success. vLLM/TEI panels have live series; gateway panels show
no data until the netpol fix in homelab-frontend PR #62 merges.
Also fixes a dead alert. alerts/cag-kv-cache-rules.yaml derived
vllm:prefix_cache_hit_rate from vllm:cache_query_hit_total and
vllm:cache_query_miss_total. Those metric names do not exist in vLLM
0.11.0 — the real series are vllm:prefix_cache_hits_total and
vllm:prefix_cache_queries_total. The recording rule produced no data, so
VLLMPrefixCacheHitRateLow could never fire.
Not included: real GPU hardware metrics (SM utilisation, framebuffer,
power, temperature). Only nvidia-device-plugin is deployed, which exposes
none of them; DCGM exporter is required. vllm:kv_cache_usage_perc and
preemption rate are the only GPU-pressure proxies available today.
Both metric sources existed but neither was scraped:
- servicemonitors/vllm.yaml was orphaned (absent from kustomization
resources:) and would not have matched anyway — it used 'port: http'
but KServe-generated Services in llm-serving have UNNAMED ports.
Switched to targetPort: 8080 (prometheus-operator v0.94.1 supports it),
which avoids editing the InferenceServices and therefore avoids a
predictor restart / weights reload.
- api-gw exposes llm_ttft_seconds, llm_itl_seconds, llm_tokens_total,
queue_full_requests_total, warmup_requests_delayed_total and
vllm_prefix_cache_hit_tokens_total, but the Deployment's
prometheus.io/scrape annotation is ignored by kube-prometheus-stack
(no additionalScrapeConfigs). Added a ServiceMonitor for it. This is
the only per-request latency source covering the two Ollama models,
which expose no metrics endpoint at all.
Ollama services are excluded from the vllm ServiceMonitor selector to
avoid permanently-DOWN targets.
Note: alerts/cag-kv-cache-rules.yaml references vllm:prefix_cache_hit_rate
derived from vllm:cache_query_hit_total/miss, which were never scraped.
Those alerts were dead; verify the metric names after the first scrape.
Actual TSDB data is ~2Gi. 100Gi over-provisioned Longhorn storage
contributed to the cluster-wide scheduling pressure; 25Gi is ample
with room for retention growth.
- Increase PVC from 20Gi to 100Gi (talos-cp-1 disk full)
- Move from az-a (talos-cp-1) to worker-1 (648GB available)
- Increase retention from 15d to 30d (95GB limit)
- Fixes Prometheus pod restarts due to disk pressure
Add ServiceMonitor for llm-serving namespace. Wire prometheus.io annotations to all vLLM pods (reasoning, ornith, embeddings, reranker). Scrape /metrics@8080 every 30s with proper relabeling.
Ingress api/api now backs onto api-gateway:8080; the kong Application, its
Helm values, plugins and llm-routes are removed. Gateway image v0.0.0 is in
the Forgejo registry and the pull secret is in the api namespace.
rock
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