Admin Bot c5a91cf647
CI / CI (pull_request) Successful in 34m5s
feat(proxy): engine-wide LLM admission control via vLLM gauges (#64)
The per-pod semaphore was not a cap: 3 replicas x 4 slots advertised 12
concurrent requests while the engine runs 4, and nothing coordinated the
replicas. Admission is now gated on the engine's own published gauges,
which is global by construction because every replica contends for the
same engine.

- new internal/proxy/engine_state.go: 2s scrape of the backend /metrics,
  hand-rolled exposition parse (no new dependency), unhealthy after 3
  consecutive failed polls, and a startup self-check that raises
  observer_degraded rather than falling back to fail-open silently
- gate: park while kv_cache_usage_perc >= 0.90 or running + waiting >=
  ADMISSION_MAX_INFLIGHT, bounded by ADMISSION_MAX_PARK_SECONDS, then
  503 + Retry-After: 5. Unknown state fails open on purpose
- streaming requests receive SSE keep-alive heartbeats while parked
- router: extract only the top-level model field instead of unmarshalling
  the whole body into a map; body cap from MAX_BODY_BYTES (1 MiB, the
  model path previously inherited the 100 MB default)
- GOMAXPROCS from the cgroup CPU quota: the container is limited to 500m
  while Go defaulted to the host core count and was CFS-throttled
- VLLM_MAX_QUEUE_DEPTH default 20 -> 8
- delete k8s/configmap.yaml: absent from kustomization.yaml, and the live
  ConfigMap of that name carries an unrelated key
- correct the llm-client NetworkPolicy comment; llm-serving-ingress now
  selects by namespace, not by that label

Observers run only for models named in ADMISSION_OBSERVE_MODELS.
reasoning is the only vLLM engine here; ornith and qwen-cpu are Ollama
and embeddings/rerank are TEI, none of which publish vllm:* series, so
observing them would hold observer_degraded at 1 permanently.

Companion change (engine flags + dashboard panels) is
riotpiao-poimen/homelab#51.
2026-09-30 17:39:47 +08:00

homelab-frontend

Production API gateway for the homelab cluster. Single entry point (api.riotpiao.com) for all services: LLM inference, workflows, queues, memory, and cluster operations.

Status: Live in production. Replaced Kong OSS entirely.


  • API Reference: See API.md — how to call every service
  • Base URL: https://api.riotpiao.com
  • Source: ssh://git.riotpiao.com:2222/rock/homelab-frontend.git

Architecture

┌─────────────┬──────────────┬────────────┐
│  Browser    │     SDK      │    CLI     │
└──────┬──────┴──────┬───────┴────┬───────┘
       │             │            │
       └─────────────┼────────────┘
                     │
                  HTTPS/TLS
                     │
       ┌─────────────┼────────────┐
       │   Cloudflare Edge        │
       │   (DDoS, caching)        │
       └──────────┬──────────────┘
                  │
            ingress-nginx
         (SSL termination)
                  │
    ┌─────────────────────────────┐
    │   homelab-frontend Gateway  │
    │   (routing, auth, limits)    │
    └──────┬───────────────────────┘
           │
    ┌──────┴───────────────────────────────────┐
    │                                           │
 /v1/*           X-Service header routing       /
(LLM)    (workflow, sqs, s3, iam, memory)    /
    │             │                           │
    ▼             ▼                           ▼
llm-serving  temporal:7233   kmsvc/Kafka, MinIO,
(vLLM, Ollama) (gRPC)        Authentik, poimen-memory
(TEI)

Design principles:

  • ✅ Single hostname, unified X-Service + X-Resource header routing
  • ✅ HTTP REST gateway → gRPC Temporal bridge (via X-Service: workflow)
  • ✅ Bearer token auth via Authentik (JWT + RBAC)
  • ✅ Streaming unbuffered (SSE, WebSocket, HTTP/2 multiplexing)
  • ✅ Per-route timeouts & rate limits
  • ✅ No cluster credentials held by gateway

Services & Capabilities

Service Method Upstream Status
LLM Chat POST /v1/chat/completions llm-serving (vLLM) ✅ Live
Embeddings POST /v1/embeddings llm-serving (TEI) ✅ Live
Reranking POST /v1/rerank llm-serving (TEI) ✅ Live
Workflows X-Service: workflow + X-Resource: {action} Temporal gRPC (7233) ✅ Live (START, DESCRIBE, SIGNAL, QUERY, etc)
Queues X-Service: sqs + X-Resource: {action} kmsvc/Kafka ✅ Live
Memory X-Service: memory + X-Resource: {action} poimen-memory ✅ Live
IAM X-Service: iam + X-Resource: {action} Authentik API ✅ Live
S3 X-Service: s3 + X-Resource: {action} MinIO ✅ Live

How to Use

1. Get a token

Human (OIDC device code):

core auth login
export TOKEN=$(cat ~/.cache/talos/authentik_id_token)

Service account (client credentials):

core mwinit login --username sa-name --password secret
export TOKEN=$(cat ~/.talos/.riotpiao-auth)

2. Call any service

Chat:

curl -X POST https://api.riotpiao.com/v1/chat/completions \
  -H "Authorization: Bearer $TOKEN" \
  -d '{
    "model": "reasoning",
    "messages": [{"role": "user", "content": "What is 2+2?"}]
  }'

Workflow (via X-Service header):

curl -X POST https://api.riotpiao.com/ \
  -H "Authorization: Bearer $TOKEN" \
  -H "X-Service: workflow" \
  -H "X-Resource: start" \
  -d '{
    "namespace": "default",
    "workflow_id": "my-workflow",
    "workflow_type": "MyWorkflow",
    "task_queue": "default"
  }'

Memory:

curl -X GET https://api.riotpiao.com/ \
  -H "Authorization: Bearer $TOKEN" \
  -H 'X-Service: memory' \
  -H 'X-Resource: query' \
  -G --data-urlencode 'query=explain machine learning'

Full examples: See API.md


Available Models

LLM (Chat & Reasoning)

  • reasoning — DeepSeek-R1-Distill-Qwen-32B (8 concurrent slots)
  • ornith:35b — Ollama 35B
  • qwen2.5:3b-instruct — Qwen 2.5 3B

Embeddings

  • nomic-ai/nomic-embed-text-v2-moe — Fast, multilingual

Reranking

  • BAAI/bge-reranker-base — Document relevance scoring

Authentication

All endpoints (except /healthz, /readyz) require:

Authorization: Bearer <jwt-token>

Tokens validated via Authentik JWKS (runtime fetched, cached, auto-rotated).

Capabilities (RBAC):

  • llm:inference — /v1/* chat/embeddings/rerank
  • workflow:execute — /workflow operations
  • memory:read / memory:write — Memory operations
  • sqs:access — Queue operations
  • s3:access — S3 operations
  • iam:admin — User/group management

Error Handling

All errors return RFC 9457 application/problem+json:

{
  "type": "https://api.example.com/problems/unknown-model",
  "title": "Unknown Model",
  "status": 400,
  "detail": "Model 'gpt-4' is not available",
  "valid_models": ["reasoning", "ornith:35b", ...]
}

Common status codes:

  • 200 OK
  • 400 Bad Request (validation, unknown model)
  • 401 Unauthorized (missing/invalid token)
  • 403 Forbidden (insufficient capability)
  • 404 Not Found (workflow, resource)
  • 429 Too Many Requests (rate limit)
  • 503 Service Unavailable (backend down)

Rate Limits

Endpoint Limit Retry-After
/v1/chat/completions 8 concurrent Yes
/v1/embeddings 10 concurrent Yes
/v1/rerank 10 concurrent Yes
/workflow 100 concurrent Yes

Hitting limit returns 429 with Retry-After header.


Timeouts

Endpoint Connect Read Write
/v1/chat 10s 1h 1h
/v1/embeddings 10s 10m 10m
/v1/rerank 10s 10m 10m
/workflow 10s 30s 10s

Client disconnects cancel upstream request immediately (no orphaned slots).


Local Development

Run without cluster, no credentials needed:

# Build
go build ./cmd/gateway

# Run locally
./gateway

# Test in another terminal
curl http://localhost:8080/healthz

Points upstreams at local stubs if not connected to cluster (see internal/config).


Code Layout

cmd/gateway/               Server entrypoint
internal/
  server/                  Router, health checks
  proxy/                   Reverse proxy, streaming, timeouts
  temporal/                Workflow handler + gRPC bridge
  serviceadapter/          X-Service dispatcher (CRD-driven)
  config/                  Route + upstream configuration
  auth/                    Authentik JWT validation
  observability/           Metrics, structured logging
k8s/
  configmap.yaml           Route definitions
  rbac.yaml                Service account, roles
  deployment.yaml          Pod spec
  networkpolicy.yaml       Ingress/egress rules
testdata/                  Fixtures for offline tests

Deployment

Deployed to Kubernetes via ArgoCD:

# Check deployment
kubectl -n api get deployment homelab-frontend

# View logs
kubectl -n api logs -l app=homelab-frontend -f

# Restart
kubectl -n api rollout restart deployment/homelab-frontend

Configuration mounted as ConfigMap (k8s/configmap.yaml).


Health Checks

# Liveness (always succeeds)
curl https://api.riotpiao.com/healthz

# Readiness (waits for config + JWKS)
curl https://api.riotpiao.com/readyz

# List available models
curl https://api.riotpiao.com/v1/models

Support

Issues: Check pod logs

kubectl -n api logs deployment/homelab-frontend

Debug config:

kubectl -n api get configmap homelab-frontend-config -o yaml

Restart pod:

kubectl -n api rollout restart deployment/homelab-frontend

Test endpoint directly:

kubectl -n api port-forward svc/homelab-frontend 8080:8080
curl http://localhost:8080/healthz

See Also

  • API.md — Complete API reference with examples
  • internal/ — Source code (handlers, routing, auth)
  • k8s/ — Kubernetes manifests
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