Files
homelab/k8s/apps/llm-serving/inferenceservice-verifier.yaml
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Story Crater Bot 4fb1c6feeb feat(gpu): serve 6 models on worker-1 via KServe — vLLM v0.11.0 (bitsandbytes) + Ollama + TEI, plus RuntimeClass/privileged-PSA prereqs and a local-NVMe StorageClass, working around Volta sm_70 limits
Layout on 4x Tesla V100 32GB (PCIe, no NVLink), all TP=1:
  GPU0+1  vLLM    DeepSeek-R1-Distill-Qwen-32B bnb-nf4  (2 replicas)
  GPU2    Ollama  ornith:35b + qwen2.5:3b-instruct      (co-resident)
  GPU3    vLLM    Qwen2.5-Math-PRM-7B                   (reward model)
  CPU     TEI     nomic-embed-text-v2-moe, bge-reranker-base

Volta constraints, each verified against live output rather than config:
- vLLM pinned v0.11.0: sm_70 dropped from CUDA_SUPPORTED_ARCHS at v0.11.1.
- AWQ hard-rejected (needs sm_75). GPTQ passes vLLM's min_capability=60 gate
  but is NUMERICALLY WRONG on sm_70 — emits garbage logits. Proven by an fp16
  control run producing correct text on an identical backend. bitsandbytes nf4
  verified correct by output.
- flashinfer's check_cuda_arch() crashes on any sm_7x (calls .isdigit() on an
  int) -> VLLM_USE_FLASHINFER_SAMPLER=0.
- xformers has no sm_70 kernel for V1's paged-attention bias, and V0 was
  removed in v0.11.0 -> TRITON_ATTN.
- Ornith is Qwen3.5-MoE hybrid-attention; vLLM added that arch after dropping
  Volta, so no build has both -> Ollama, which also multiplexes a second model
  on the same card for free.

Cluster prereqs that were absent:
- RuntimeClass nvidia: the Talos toolkit extension registers the containerd
  handler but not the k8s object; without it every pod is rejected at admission.
- gpu-system pinned to privileged PSA: a device plugin cannot satisfy the
  cluster-default baseline, it must mount hostPath.
- device-plugin affinity=null: the chart requires NFD labels that do not exist
  here, so it matched zero nodes and reported desiredNumberScheduled=0 silently.
- Recreate strategy on GPU services: with GPUs allocated exactly 4/4, a
  RollingUpdate surge pod has no card and deadlocks the rollout.
- longhorn-llm-local SC (1 replica, strict-local, disk tag llm): the default
  3-replica class could not place the volume at all (every control-plane disk
  was at its over-provisioning ceiling), and this keeps ~60GB of weights on
  worker-1's own NVMe instead of reading them over the network.

deploy-gpu-serving.sh sequences ArgoCD syncs (or helm/kubectl in --manual mode)
and never applies a manifest absent from git; doctor/unstick/teardown stages
exist so this is diagnosable without ad-hoc kubectl archaeology.
2026-08-13 07:02:53 -07:00

102 lines
3.6 KiB
YAML

# Verifier — Qwen2.5-Math-PRM-7B, step-level process reward model, vLLM.
#
# Model choice was constrained by vLLM v0.11.0's registry: its arch
# (Qwen2ForProcessRewardModel) is natively registered, whereas the smaller
# community PRMs are Qwen2ForTokenClassification / Qwen2ForPrmModel, neither of
# which v0.11.0 can load (ForTokenClassification is absent from
# _SUFFIX_TO_DEFAULTS, so it won't even auto-convert).
#
# --runner pooling, NOT --task reward: --task is [DEPRECATED] in v0.11.0.
# Scoring goes to /pooling, not /v1/completions — this is a reward model, it
# returns scores, not tokens.
#
# Gets a whole dedicated GPU despite only needing ~15Gi: it sits on the
# harness's critical path (every reasoning->action->verify iteration waits on
# it), so isolation from the generation engines' decode loops matters more than
# the idle VRAM.
apiVersion: serving.kserve.io/v1beta1
kind: InferenceService
metadata:
name: verifier
labels:
app.kubernetes.io/name: llm-verifier
app.kubernetes.io/part-of: llm-serving
spec:
predictor:
minReplicas: 1
# Recreate, not the default RollingUpdate: GPUs are allocated exactly 4/4,
# so a surge pod has no card to claim and sits Pending while the old pod is
# never torn down — a deadlock. Recreate tears down first, accepting a brief
# gap during updates.
deploymentStrategy:
type: Recreate
maxReplicas: 1
nodeSelector:
kubernetes.io/hostname: worker-1
runtimeClassName: nvidia
containers:
- name: kserve-container
image: vllm/vllm-openai:v0.11.0@sha256:014a95f21c9edf6abe0aea6b07353f96baa4ec291c427bb1176dc7c93a85845c
args:
- --model=Qwen/Qwen2.5-Math-PRM-7B
- --served-model-name=verifier
# Pooling runner => reward scoring. Weights are bf16; Volta needs fp16.
- --runner=pooling
- --dtype=float16
- --tensor-parallel-size=1
- --max-model-len=4096
- --max-num-seqs=8
- --host=0.0.0.0
- --port=8080
env:
# flashinfer's check_cuda_arch() has an upstream bug that crashes on
# ANY sm_7x GPU: `elif major == 7 and minor.isdigit()` calls .isdigit()
# on an int, so instead of reporting "unsupported" it raises
# AttributeError: 'int' object has no attribute 'isdigit'
# and engine init dies. Default is None (auto-detect), which walks
# straight into that path. 0 disables the flashinfer sampler outright.
# Only affects the generate runner — the verifier (pooling) never hits
# the sampler, which is why it started fine and this did not.
- name: VLLM_USE_FLASHINFER_SAMPLER
value: "0"
- name: VLLM_ATTENTION_BACKEND
value: XFORMERS
- name: HF_HOME
value: /mnt/models
ports:
- containerPort: 8080
protocol: TCP
resources:
requests:
cpu: "4"
memory: 8Gi
nvidia.com/gpu: "1"
limits:
cpu: "16"
memory: 16Gi
nvidia.com/gpu: "1"
volumeMounts:
- name: models
mountPath: /mnt/models
- name: shm
mountPath: /dev/shm
startupProbe:
httpGet:
path: /health
port: 8080
periodSeconds: 15
failureThreshold: 60
readinessProbe:
httpGet:
path: /health
port: 8080
periodSeconds: 10
volumes:
- name: models
persistentVolumeClaim:
claimName: llm-models
- name: shm
emptyDir:
medium: Memory
sizeLimit: 1Gi