[CI] Add Nixl+OffloadingConnector e2e integration tests (#39200)

Signed-off-by: NickLucche <nlucches@redhat.com>

.buildkite/test_areas/distributed.yaml

@@ -268,6 +268,20 @@ steps:
     - uv pip install --system -r /vllm-workspace/requirements/kv_connectors.txt
     - HYBRID_SSM=1 bash v1/kv_connector/nixl_integration/config_sweep_accuracy_test.sh
 
+- label: MultiConnector (Nixl+Offloading) PD accuracy (2 GPUs)
+  timeout_in_minutes: 30
+  working_dir: "/vllm-workspace/tests"
+  num_devices: 2
+  source_file_dependencies:
+    - vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py
+    - vllm/distributed/kv_transfer/kv_connector/v1/multi_connector.py
+    - vllm/distributed/kv_transfer/kv_connector/v1/offloading_connector.py
+    - vllm/distributed/kv_transfer/kv_connector/v1/offloading/
+    - tests/v1/kv_connector/nixl_integration/
+  commands:
+    - uv pip install --system -r /vllm-workspace/requirements/kv_connectors.txt
+    - bash v1/kv_connector/nixl_integration/run_multi_connector_accuracy_test.sh
+
 - label: NixlConnector PD + Spec Decode acceptance (2 GPUs)
   timeout_in_minutes: 30
   device: a100

tests/v1/kv_connector/nixl_integration/run_multi_connector_accuracy_test.sh

+#!/bin/bash
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+#
+# Integration accuracy test for MultiConnector (NixlConnector + OffloadingConnector).
+#
+# Launches a P/D setup where both prefill and decode instances use MultiConnector
+# wrapping NixlConnector and OffloadingConnector, then runs gsm8k accuracy via
+# test_accuracy.py.
+#
+# By default runs two configurations:
+#   1. Normal KV layout (NixlConnector without cross-layer blocks)
+#   2. Cross-layer KV layout (NixlConnector with enable_cross_layers_blocks)
+#
+# Usage:
+#   bash tests/v1/kv_connector/nixl_integration/run_multi_connector_accuracy_test.sh
+#
+# Environment variables:
+#   MODEL_NAMES              - model to test (default: Qwen/Qwen3-0.6B)
+#   GPU_MEMORY_UTILIZATION   - GPU memory fraction (default: 0.6)
+#   VLLM_SERVE_EXTRA_ARGS    - comma-separated extra args for vllm serve
+#   SKIP_CROSS_LAYERS        - set to 1 to skip the cross-layer layout test
+#   SKIP_NORMAL_LAYOUT       - set to 1 to skip the normal layout test
+set -xe
+
+# ── Configuration ────────────────────────────────────────────────────────
+
+MODEL_NAMES=${MODEL_NAMES:-}
+if [[ -n "$MODEL_NAMES" ]]; then
+  MODELS=("$MODEL_NAMES")
+else
+  MODELS=("Qwen/Qwen3-0.6B")
+fi
+
+GPU_MEMORY_UTILIZATION=${GPU_MEMORY_UTILIZATION:-0.6}
+BLOCK_SIZE=${BLOCK_SIZE:-128}
+VLLM_SERVE_EXTRA_ARGS=${VLLM_SERVE_EXTRA_ARGS:-}
+
+GIT_ROOT=$(git rev-parse --show-toplevel)
+SMI_BIN=$(which nvidia-smi || which rocm-smi || echo "")
+
+# ── KV transfer configs ─────────────────────────────────────────────────
+
+# Normal layout: OffloadingConnector prefers cross-layer but NixlConnector
+# does not, so MultiConnector.prefer_cross_layer_blocks = False.
+KV_CONFIG_NORMAL='{
+  "kv_connector":"MultiConnector",
+  "kv_role":"kv_both",
+  "kv_connector_extra_config":{
+    "connectors":[
+      {"kv_connector":"NixlConnector","kv_role":"kv_both"},
+      {"kv_connector":"OffloadingConnector","kv_role":"kv_both",
+       "kv_connector_extra_config":{"cpu_bytes_to_use":1000000000}}
+    ]
+  }
+}'
+# Remove whitespace for CLI safety
+KV_CONFIG_NORMAL=$(echo "$KV_CONFIG_NORMAL" | tr -d '[:space:]')
+
+# Cross-layer layout: both connectors prefer cross-layer blocks.
+KV_CONFIG_CROSS_LAYERS='{
+  "kv_connector":"MultiConnector",
+  "kv_role":"kv_both",
+  "kv_connector_extra_config":{
+    "connectors":[
+      {"kv_connector":"NixlConnector","kv_role":"kv_both",
+       "kv_connector_extra_config":{"enable_cross_layers_blocks":"True"}},
+      {"kv_connector":"OffloadingConnector","kv_role":"kv_both",
+       "kv_connector_extra_config":{"cpu_bytes_to_use":1000000000}}
+    ]
+  }
+}'
+KV_CONFIG_CROSS_LAYERS=$(echo "$KV_CONFIG_CROSS_LAYERS" | tr -d '[:space:]')
+
+# ── Helpers ──────────────────────────────────────────────────────────────
+
+trap 'kill $(jobs -pr) 2>/dev/null' SIGINT SIGTERM EXIT
+
+wait_for_server() {
+  local port=$1
+  timeout 1200 bash -c "
+    until curl -s localhost:${port}/v1/completions > /dev/null; do
+      sleep 1
+    done" && return 0 || return 1
+}
+
+cleanup_instances() {
+  echo "Cleaning up any running vLLM instances..."
+  pkill -f "vllm serve" || true
+  sleep 2
+}
+
+get_num_gpus() {
+  if [[ "$SMI_BIN" == *"nvidia"* ]]; then
+    $SMI_BIN --query-gpu=name --format=csv,noheader | wc -l
+  elif [[ "$SMI_BIN" == *"rocm"* ]]; then
+    $SMI_BIN -l | grep -c GPU
+  else
+    echo "1"
+  fi
+}
+
+# ── Run tests for one model with a given KV config ───────────────────────
+
+run_tests_for_model() {
+  local model_name=$1
+  local kv_config=$2
+  local label=$3
+
+  echo "================================================================"
+  echo "Testing model: $model_name ($label)"
+  echo "KV config: $kv_config"
+  echo "================================================================"
+
+  local PREFILL_PORT=8100
+  local DECODE_PORT=8200
+  local PREFILL_GPU=0
+  local DECODE_GPU=1
+  local PREFILL_SIDE_CHANNEL_PORT=5559
+  local DECODE_SIDE_CHANNEL_PORT=5659
+
+  # ── Start prefill instance ──
+  echo "Starting prefill instance on GPU $PREFILL_GPU, port $PREFILL_PORT"
+  BASE_CMD="CUDA_VISIBLE_DEVICES=$PREFILL_GPU \
+    VLLM_KV_CACHE_LAYOUT='HND' \
+    UCX_NET_DEVICES=all \
+    VLLM_NIXL_SIDE_CHANNEL_PORT=$PREFILL_SIDE_CHANNEL_PORT \
+    vllm serve $model_name \
+    --port $PREFILL_PORT \
+    --enforce-eager \
+    --block-size ${BLOCK_SIZE} \
+    --gpu-memory-utilization $GPU_MEMORY_UTILIZATION \
+    --tensor-parallel-size 1 \
+    --kv-transfer-config '$kv_config'"
+
+  if [[ -n "$VLLM_SERVE_EXTRA_ARGS" ]]; then
+    IFS=',' read -r -a extra_args <<< "$VLLM_SERVE_EXTRA_ARGS"
+    for arg in "${extra_args[@]}"; do
+      BASE_CMD="${BASE_CMD} $arg"
+    done
+  fi
+  eval "$BASE_CMD &"
+
+  # ── Start decode instance ──
+  echo "Starting decode instance on GPU $DECODE_GPU, port $DECODE_PORT"
+  BASE_CMD="CUDA_VISIBLE_DEVICES=$DECODE_GPU \
+    VLLM_KV_CACHE_LAYOUT='HND' \
+    UCX_NET_DEVICES=all \
+    VLLM_NIXL_SIDE_CHANNEL_PORT=$DECODE_SIDE_CHANNEL_PORT \
+    vllm serve $model_name \
+    --port $DECODE_PORT \
+    --enforce-eager \
+    --block-size ${BLOCK_SIZE} \
+    --gpu-memory-utilization $GPU_MEMORY_UTILIZATION \
+    --tensor-parallel-size 1 \
+    --kv-transfer-config '$kv_config'"
+
+  if [[ -n "$VLLM_SERVE_EXTRA_ARGS" ]]; then
+    IFS=',' read -r -a extra_args <<< "$VLLM_SERVE_EXTRA_ARGS"
+    for arg in "${extra_args[@]}"; do
+      BASE_CMD="${BASE_CMD} $arg"
+    done
+  fi
+  eval "$BASE_CMD &"
+
+  # ── Wait for servers ──
+  echo "Waiting for prefill instance on port $PREFILL_PORT to start..."
+  wait_for_server "$PREFILL_PORT"
+  echo "Waiting for decode instance on port $DECODE_PORT to start..."
+  wait_for_server "$DECODE_PORT"
+
+  # ── Start proxy ──
+  PROXY_CMD="python3 ${GIT_ROOT}/tests/v1/kv_connector/nixl_integration/toy_proxy_server.py --port 8192"
+  PROXY_CMD+=" --prefiller-hosts localhost"
+  PROXY_CMD+=" --prefiller-ports $PREFILL_PORT"
+  PROXY_CMD+=" --decoder-hosts localhost"
+  PROXY_CMD+=" --decoder-ports $DECODE_PORT"
+
+  echo "Starting proxy server with command: $PROXY_CMD"
+  $PROXY_CMD &
+  sleep 5
+
+  # ── Run accuracy test ──
+  echo "Running accuracy tests for $model_name ($label)"
+  TEST_MODEL=$model_name python3 -m pytest -s -x \
+    "${GIT_ROOT}"/tests/v1/kv_connector/nixl_integration/test_accuracy.py
+
+  # ── Cleanup ──
+  cleanup_instances
+  sleep 3
+}
+
+# ── Main ─────────────────────────────────────────────────────────────────
+
+for model in "${MODELS[@]}"; do
+  if [[ -z "${SKIP_NORMAL_LAYOUT:-}" ]]; then
+    run_tests_for_model "$model" "$KV_CONFIG_NORMAL" "MultiConnector normal layout"
+  fi
+
+  if [[ -z "${SKIP_CROSS_LAYERS:-}" ]]; then
+    run_tests_for_model "$model" "$KV_CONFIG_CROSS_LAYERS" "MultiConnector cross-layer layout"
+  fi
+done
+
+echo "All MultiConnector accuracy tests passed!"