> This page is for version v1.4.1.
> For other versions, use one of these documentation indexes:
> - Latest (v1.5.1) (default): https://docs.nvidia.com/dynamo/latest/llms.txt
> - dev: https://docs.nvidia.com/dynamo/dev/llms.txt
> - v1.5.1: https://docs.nvidia.com/dynamo/v1.5.1/llms.txt
> - v1.5.0: https://docs.nvidia.com/dynamo/v1.5.0/llms.txt
> - v1.4.2: https://docs.nvidia.com/dynamo/v1.4.2/llms.txt
> - v1.4.1: https://docs.nvidia.com/dynamo/v1.4.1/llms.txt
> - v1.4.0: https://docs.nvidia.com/dynamo/v1.4.0/llms.txt
> - v1.3.0: https://docs.nvidia.com/dynamo/v1.3.0/llms.txt
> - v1.2.1: https://docs.nvidia.com/dynamo/v1.2.1/llms.txt
> - v1.2.0: https://docs.nvidia.com/dynamo/v1.2.0/llms.txt
> - v1.1.1: https://docs.nvidia.com/dynamo/v1.1.1/llms.txt
> - v1.1.0: https://docs.nvidia.com/dynamo/v1.1.0/llms.txt
> - v1.0.2: https://docs.nvidia.com/dynamo/v1.0.2/llms.txt
> - v1.0.1: https://docs.nvidia.com/dynamo/v1.0.1/llms.txt
> - v1.0.0: https://docs.nvidia.com/dynamo/v1.0.0/llms.txt
> - v0.9.1: https://docs.nvidia.com/dynamo/v-0-9-1/llms.txt
> - v0.9.0: https://docs.nvidia.com/dynamo/v-0-9-0/llms.txt
> - v0.8.1: https://docs.nvidia.com/dynamo/v-0-8-1/llms.txt
> - v0.8.0: https://docs.nvidia.com/dynamo/v-0-8-0/llms.txt
> - v0.7.1: https://docs.nvidia.com/dynamo/v-0-7-1/llms.txt
> - v0.7.0: https://docs.nvidia.com/dynamo/v-0-7-0/llms.txt

> For clean Markdown content of this page, append .md to this URL. For the complete documentation index, see https://docs.nvidia.com/dynamo/llms.txt. For full content including API reference and SDK examples, see https://docs.nvidia.com/dynamo/llms-full.txt.

# vLLM-Omni Configuration

The vLLM-Omni backend uses a dedicated entrypoint: `python -m dynamo.vllm.omni`. This page documents its CLI flags. For deployment guides and per-modality examples, see the [Diffusion Overview](/dynamo/v1.4.1/diffusion/overview).

> **Note**
>
> These are the vLLM-Omni orchestration flags. The omni worker also accepts the same underlying vLLM engine arguments and the cross-cutting [Dynamo Runtime](/dynamo/v1.4.1/reference/components/runtime-configuration) flags (`--namespace`, `--endpoint`, and others).

## General Flags

**`--omni`** `flag`

Enable the vLLM-Omni orchestrator (required for all omni workloads).

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**`--output-modalities`** `text | image | video | audio`

Output modality the worker registers endpoints for.

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**`--stage-configs-path`** `path`

Path to stage config YAML (optional; vLLM-Omni uses model defaults if omitted).

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**`--boundary-ratio`** `float` — default: 0.875

MoE expert switching boundary.

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**`--flow-shift`** `float`

Scheduler flow\_shift (5.0 for 720p, 12.0 for 480p).

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**`--default-video-fps`** `int` — default: 16

Default frames per second for generated videos.

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## Memory & Performance

**`--vae-use-slicing`** `flag`

Enable VAE slicing for memory optimization.

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**`--vae-use-tiling`** `flag`

Enable VAE tiling for memory optimization.

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**`--enable-layerwise-offload`** `flag`

Enable layerwise offloading on DiT modules to reduce GPU memory.

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**`--layerwise-num-gpu-layers`** `int` — default: 1

Number of ready layers to keep on GPU during generation.

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**`--enforce-eager`** `flag`

Disable torch.compile for diffusion models.

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**`--enable-cpu-offload`** `flag`

Enable CPU offloading for diffusion models.

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## Diffusion Cache

**`--cache-backend`** `cache_dit | tea_cache`

Diffusion cache backend.

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**`--cache-config`** `json`

Cache configuration as a JSON string (overrides defaults).

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**`--enable-cache-dit-summary`** `flag`

Enable cache-dit summary logging after diffusion forward passes.

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## Parallelism

**`--ulysses-degree`** `int` — default: 1

GPUs for Ulysses sequence parallelism in diffusion.

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**`--ring-degree`** `int` — default: 1

GPUs for ring sequence parallelism in diffusion.

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**`--cfg-parallel-size`** `int` — default: 1

GPUs for classifier-free guidance parallelism (1 or 2).

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## Disaggregated Mode

See [vLLM-Omni Disaggregated Serving](/dynamo/v1.4.1/knowledge-base/modular-components/backends/v-llm/v-llm-omni-disaggregated-serving) for usage.

**`--stage-id`** `int`

Run as a single-stage worker for the given stage ID. Requires `--stage-configs-path`.

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**`--omni-router`** `flag`

Run as the stage router. Requires `--stage-configs-path`. Mutually exclusive with `--stage-id`.

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## Media Storage

**`--media-output-fs-url`** `url` — default: file:///tmp/dynamo\_media

Filesystem URL for storing generated media.

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**`--media-output-http-url`** `url`

Base URL for rewriting media paths in responses (optional).

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