`vllm-meromero-rp` had been restarting since 2026-08-24 18:2x, 13 times by the
time it was looked at, taking both the `char-rp` and `char-rp-reasoning`
gateway aliases down with it (they resolve to the same seat on :8016 —
hosted_vllm/char-rp and hosted_vllm/char-rp-thinking).
Root cause is CUDA OOM on ana-ml2 GPU0, which the startup logs hide well: the
engine gets through weights, torch.compile and CUDA-graph capture looking
entirely healthy, then dies at KV-cache allocation with
`torch.OutOfMemoryError: ... 195.19 MiB is free`.
GPU0 is shared with `vllm-gen`. gen is configured at 0.43 but actually holds
~45.6 GiB of the 94.97 GiB card, because --gpu-memory-utilization sizes the KV
cache and does not account for CUDA context, graphs and non-torch overhead.
This seat was at 0.51, so the pair was committed to 0.94 of the card with about
0.6 GiB of real headroom. That fit on 08-21 and stopped fitting today.
0.47 restores ~4.8 GiB of margin and costs nothing usable: KV cache 27.36 ->
23.56 GiB, 430,825 -> 371,023 tokens against a max-model-len of 262,144, so the
pool still holds 1.4x a full-length sequence. What is lost is concurrent long
requests, not context.
Verified through the gateway rather than at the container: char-rp returns 200
with content, char-rp-reasoning returns 200 with both content and
reasoning_content populated. Seat is healthy with RestartCount 0.
The arithmetic and the "check used_memory, not the flag" warning are written
into the env template, because the next person to raise either budget needs to
lower the other in the same change.
vh