dynamo-prime-rl-integration

[biswapanda]

Purpose

Extend vLLM's existing native Rust gRPC and token-in/token-out surfaces so an out-of-process Dynamo sidecar can drive aggregated and disaggregated inference without introducing a separate OpenEngine schema.

Companion PRs:

• Prime-RL integration: PrimeIntellect-ai/prime-rl#3062
• Dynamo sidecar integration: ai-dynamo/dynamo#11804

Exact tested heads:

Repository	Commit
vLLM	e74fc3f1b06258e25519a5d5ed4d9a1b05d9a1cb
Dynamo	fc556d992cd2525eaf6ae0f612f31a46db2e5a7b
Prime-RL	7a8f90b2495e344f5b9198e20f418c472018b1ad

Native protocol and server

• Extend the existing vLLM gRPC service rather than wrapping it in openengine.v1.
• Preserve sampling, prompt logprobs, priority, cache salt, DP-rank routing, request identity, extra arguments, LoRA selection, multimodal inputs, usage, finish metadata, KV-transfer metadata, and routed experts.
• Expose structured server/model/parallelism metadata and engine failure through the native control service.
• Keep EngineCore utility calls cancellation-safe and preserve managed Python EngineCore ownership and shutdown ordering.
• Coordinate managed data-parallel EngineCore processes through one handshake owner while exposing the validated logical DP span.

The branch is restacked on the native control/inference split already present in upstream vLLM. It removes fork duplicates, shares drain state through AppState, reconciles current protocol output types, and retains the post-review native gRPC fixes needed by the Dynamo sidecar.

Prime-RL boundary

Prime-RL main now pins vLLM 0.26.0 and imports vllm.entrypoints.scale_out.token_in_token_out directly. The Prime companion branch contains no import-layout probing or compat.py shim. Prime delegates validation, rendering, sampling, multimodal preprocessing, streaming, usage, logprobs, cancellation, and response construction to this canonical vLLM package, retaining only KV handoff and routed-expert compaction.

Prime reaches vLLM's existing HTTP administration surface through endpoints discovered from Dynamo. This PR owns no Prime configuration, trainer logic, Dynamo discovery, Helm, DGD, Slurm, prime_rl.engine.v2, or openengine.v1 schema.

Validation

The exact final ARM64 stack passed its DIND build/import gates and 35 focused Prime-side configuration, discovery, broadcaster, serving-adapter, and topology-rank tests. Explicit compatibility gates confirmed that ordinary non-Dynamo clients retain the legacy broadcaster payload and rank calculation.

The stack was deployed as q06v4i-0803 in bis-rl-3 with one aggregated inference GPU running this vLLM-rs/Python EngineCore plus a separate Dynamo sidecar and one external Prime trainer GPU. Qwen3-0.6B Math completed three trainer and orchestrator steps, three policy reloads, and a post-update HTTP 200 generation gate. The worker generated 14,510 tokens at 172.21 tokens/s aggregate with zero restarts.

Images:

nvcr.io/nvidian/dynamo-dev/biswa@sha256:be98b7cbbea4f3053eb20ad0d0596beab6644f02adc4d01c94ec845603c225dc
nvcr.io/nvidian/dynamo-dev/biswa@sha256:6740b20164a7091b252046b98786fbf39a18902b463eeb5b480384de4e9f4cfb

The checkpoint reload path emitted a RotaryEmbedding: Failed to load weights warning, but every reload call completed, policy versions advanced, and post-update generation passed. This warning remains a follow-up item.

Review map

• rust/proto/vllm_grpc.proto
• rust/src/server/src/grpc/
• rust/src/engine-core-client/
• native LoRA lifecycle and registry modules
• vllm/v1/engine/core.py and managed-DP transport initialization

[github-actions]

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