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/ace-step/Dockerfile

@@ -0,0 +1,66 @@
+# Custom Dockerfile for ACE-Step 1.5.
+#
+# Mirrors upstream's Dockerfile structure, but fixes a CUDA-version
+# mismatch that crashloops the upstream image as of April 2026:
+#   * upstream's requirements.txt lists `torch torchvision torchaudio`
+#     with no version pins;
+#   * upstream's pip install uses `--extra-index-url cu126`, which is
+#     a FALLBACK only — pypi default wins for resolution;
+#   * pypi-default torch is now cu13, so torch installs cu13 + the
+#     cu126 fallback only kicks in for torchvision/torchaudio →
+#     `RuntimeError: Detected that PyTorch and torchvision were compiled
+#     with different CUDA major versions`.
+#
+# Fix: install torch/torchvision/torchaudio FIRST from the cu126 index
+# (forced via --index-url, not --extra-index-url). Then `pip install
+# -r requirements.txt` sees they're already satisfied and leaves them
+# alone.
+#
+# Also: command is `python3 infer-api.py` (REST), not `gui.py` (Gradio)
+# — see compose.yaml command override; CMD here is the same default
+# so the image works standalone too.
+FROM nvidia/cuda:12.6.0-runtime-ubuntu22.04 AS base
+
+ENV PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONUNBUFFERED=1 \
+    HF_HUB_ENABLE_HF_TRANSFER=1 \
+    DEBIAN_FRONTEND=noninteractive
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        python3.10 \
+        python3-pip \
+        python3-venv \
+        python3-dev \
+        build-essential \
+        git \
+        curl \
+        ca-certificates \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/* \
+    && ln -sf /usr/bin/python3 /usr/bin/python
+
+RUN python -m venv /opt/venv
+ENV PATH="/opt/venv/bin:$PATH"
+
+WORKDIR /app
+
+# Clone upstream. Bake the SHA into a layer-cache key so a different
+# SHA invalidates everything below.
+ARG ACE_STEP_REF=main
+RUN git clone https://github.com/ace-step/ACE-Step.git . \
+    && git checkout ${ACE_STEP_REF} \
+    && echo "ace-step ref: $(git rev-parse HEAD)"
+
+# Pre-install torch/torchvision/torchaudio from the cu126 index — this
+# satisfies the unpinned entries in requirements.txt so the next pip
+# install doesn't re-resolve them from pypi default (cu13).
+RUN pip install --no-cache-dir --upgrade pip \
+    && pip install --no-cache-dir \
+        torch torchvision torchaudio \
+        --index-url https://download.pytorch.org/whl/cu126 \
+    && pip install --no-cache-dir hf_transfer peft \
+    && pip install --no-cache-dir -r requirements.txt \
+    && pip install --no-cache-dir .
+
+EXPOSE 8000
+CMD ["python3", "infer-api.py"]