ace-step + stable-audio-open: deploy music + SFX generation to irv-ml1

Two new audio-generation stacks alongside the TTS slate:

ace-step :8210 — Apache 2.0 music generation foundation model
(hybrid diffusion + LLM). Lyric-aware multi-minute songs. ~10-12 GB
VRAM during inference, A6000-pinned. Custom Dockerfile patches
upstream's torch/cu126 resolution bug (--extra-index-url cu126 was
falling back to pypi-default cu13 wheels, mismatching torchvision).

stable-audio-open :8211 — Stability AI 1.21B latent-diffusion SFX +
ambience. Up to 47s clips at 44.1 kHz. ~6 GB VRAM in fp16,
A6000-pinned. Custom FastAPI shim around diffusers' StableAudioPipeline
(no upstream HTTP server). Dockerfile pins torchsde explicitly —
diffusers doesn't pull it as a hard dep but
CosineDPMSolverMultistepScheduler needs it.

stacks/stable-audio-open/.env.example

@@ -0,0 +1,48 @@
+# Stable Audio Open 1.0 stack tunables. Copy to `.env` on irv-ml1
+# before deploying.
+
+# ── image ────────────────────────────────────────────────────────────
+# Local image tag — bump when you change Dockerfile or server.py to
+# force a fresh build.
+SAO_TAG=v1
+
+# Which Stable Audio model to load. As of 2026-04 the only released
+# checkpoint is 1.0; future revisions can swap here without touching
+# compose.yaml or server.py.
+SAO_MODEL=stabilityai/stable-audio-open-1.0
+
+# ── network ──────────────────────────────────────────────────────────
+# Host port (container listens on 8000 internally).
+# Reservations on irv-ml1: 8188 ComfyUI, 8190 CosyVoice, 8191 Qwen3-TTS,
+# 8192 IndexTTS-2, 8193 Kokoro, 8194 VibeVoice, 8195 Fish, 8196
+# Chatterbox, 8197 Voxtral, 8210 ACE-Step (music), 8765 Parakeet ASR.
+SAO_PORT=8211
+SAO_BIND=0.0.0.0
+
+# ── runtime / GPU ────────────────────────────────────────────────────
+# GPU pinning. "0" = RTX 3090 (24 GB), "1" = RTX A6000 (48 GB).
+# A6000 (1) recommended — Fish s2-pro lives there at ~17 GB; SAO adds
+# ~6 GB practical (model fp16 + small VAE working set), and ACE-Step
+# adds another ~12 GB during inference. Total ~35 GB / 48 GB still
+# leaves headroom. The 3090 is full with the TTS slate.
+SAO_GPU_DEVICES=1
+
+# ── HuggingFace auth ─────────────────────────────────────────────────
+# HF token — REQUIRED. Stable Audio Open is gated; you must:
+#   1. Visit https://huggingface.co/stabilityai/stable-audio-open-1.0
+#      and accept the Stability AI Community License (one click).
+#   2. Generate a read token at
+#      https://huggingface.co/settings/tokens.
+#   3. Paste it here.
+# Without this, the first model download 401s and the container
+# crashloops.
+SAO_HF_TOKEN=
+
+# ── persistent storage on the host ───────────────────────────────────
+# HF cache — first start pulls the model (~6 GB) into this dir.
+# Persistent across container recreates so we don't re-pull.
+SAO_CACHE_DIR=/worktank/stable-audio-open/hf_cache
+
+# Generated audio output — clients can pull from here for any flow
+# that wants a file path instead of a streamed WAV body.
+SAO_OUTPUTS_DIR=/worktank/stable-audio-open/outputs