Critical finding: flipping vllm_service_enabled/state=true/started and
restarting llama-swap alongside it broke llama-swap's ability to load
ANY of its own generative models -- every /v1/chat/completions request
against Qwen3.8-27B-Q4_K_M or Qwen3-8B aux models failed with
'upstream command exited prematurely' (llama-server OOM at spawn,
~1.8GB free on this 24GB card once vLLM's ~22.8GB was claimed).
Confirmed by direct A/B: same request 500s with vLLM running, 200s
seconds after stopping it.
This breaks 21 Hermes agent profiles' aux-model tasks (skills_hub,
approval, mcp, title_generation, profile_describer, compression) plus
OpenViking's VLM -- a far larger blast radius than Hindsight's single
LLM endpoint. Reverted:
- vllm_service_enabled/state back to role defaults (false/stopped) --
vLLM stays staged, startable for a brief validated shadow window,
NOT safe to leave resident in production.
- Hindsight's HINDSIGHT_API_LLM_BASE_URL back to llama-swap
(astro-orbiter:8001, Qwen3.8-27B-Q4_K_M) and the API key secret
source back to the Nous fallback item (pre-task state) --
the vLLM cutover, while functionally validated in isolation
(health, /v1/chat/completions, and a live hindsight_retain+recall
round-trip all succeeded), requires continuous vLLM availability
which is now known to be unsafe on this card.
Comment posted on t_6dff1ecc: teardown remains correctly blocked --
full cutover is not achievable within this card's VRAM budget as
currently scoped. Needs a human decision on aux-model migration
strategy (see roles/deploy-vllm README's 'Critical architectural
finding' section) before any further progress.
- vllm.service.j2: branch on role==embedding for --runner pooling
--convert embed, --no-enable-prefix-caching, per-model
trust_remote_code toggle (needed for nomic-embed-text-v1.5's custom
NomicBertModel code), and enforce_eager toggle (needed to avoid CUDA
graph capture OOM when co-resident with another vLLM process on this
24GB card).
- tasks/verify.yml: split completions vs embedding smoke tests --
embedding-mode instances don't serve /v1/completions. Assert a
non-empty embedding vector, not just HTTP 200.
- host_vars/astro-orbiter: enable nomic-embed-text-v1.5 (port 8020),
lower primary model's gpu_memory_utilization 0.95->0.90 + add
enforce_eager after finding 0.95 crash-looped 6-7x before stabilizing
with co-resident nomic-embed (real fix, confirmed via NRestarts=0
after clean stop/start, not luck).
- Hindsight (values.yaml + externalsecret.yaml): cut LLM + embeddings
over to vLLM (:8000, :8020), wire the previously-unset
HINDSIGHT_API_EMBEDDINGS_* env vars for the first time, and swap the
API key secret source from the Nous fallback item to vllm/api-key
(vLLM enforces real auth, llama-swap did not).
- README: document the embedding-mode branch, VRAM findings, and a
genuine architecture gap -- vLLM's one-model-per-process design
cannot replace llama-swap's 5-model LRU roster on this 24GB card, so
21 Hermes profiles' aux-model consumers (Qwen3-8B-no_think,
Phi-3.5-mini, Meta-Llama-3.1-8B, Qwen2.5-Coder-14B) and OpenViking's
VLM stay on llama-swap. Full teardown (t_6dff1ecc) needs a human
decision on the aux-model strategy before it can proceed.
Idempotent vLLM OpenAI-compatible serving role, staged-first (does not
start/enable the systemd unit or touch production traffic by default).
Validated end-to-end against astro-orbiter in a brief shadow window
(llama-swap stopped ~5 min, per homelab-llm-inference skill's documented
shadow-validation pattern):
- /health 200, /v1/models returns Qwen2.5-32B-Instruct-AWQ,
/v1/completions live smoke test passes, clean journalctl
- 3 consecutive full-role runs confirmed changed=0 (idempotent)
- production restored: llama-swap active, /v1/embeddings against
nomic-embed-text-v1.5 confirmed still working (Hindsight retain path)
Deviates from the original spec's model choices (Qwen2.5-32B-Instruct /
Qwen3-8B-Instruct bf16) to use the official Qwen AWQ pre-quantized variants
instead -- vLLM does not do safe on-the-fly quantization on this host
(bitsandbytes OOM history) and unquantized bf16 32B does not fit 24GB VRAM.
Two real bugs found+fixed during first-start validation (systemd-only
repro, not visible via interactive SSH testing):
1. ninja not on systemd's minimal PATH -> vLLM torch.compile
FileNotFoundError. Fixed via explicit PATH env in the unit.
2. FlashInfer sampler JIT fails to compile on RTX 3090 (SM86) --
known upstream issue class (vLLM GH #23023, #44305). Fixed via
VLLM_USE_FLASHINFER_SAMPLER=0 (falls back to native sampler).
Also fixed a real idempotency bug: force-upgrading setuptools to latest
fought with vLLM's own setuptools<81.0.0 pin, causing an install/downgrade
flip-flop (changed:true) on every run.
vllm_service_enabled defaults to false -- a host reboot must not
auto-start vLLM and VRAM-collide with the still-live llama-swap production
service. Cutover (enabling + starting + migrating consumers) is an
explicit, separate step outside this role, gated on adding embedding-mode
support (--task embed) for nomic-embed-text-v1.5, which this role does
not yet implement (Hindsight retain still depends on llama-swap's
nomic-embed until that follow-up lands).
Role: roles/deploy-vllm/ (defaults/handlers/meta/tasks/templates/README)
Playbook: playbooks/day1_deploy_vllm.yml
