Files
William Lin 7d61590213 [bugfix] Fix the CUDA device of Ray workers on multi-GPU nodes (#1932)
Ray sets CUDA_VISIBLE_DEVICES of each GPU actor to the GPU of that actor. The
import of fastvideo initializes CUDA, so the executor cannot change the device
list later. On a node with more than one GPU, each worker after the first worker
failed with "invalid device ordinal".

On NVIDIA GPUs, each worker actor now keeps the device list of its raylet
(RAY_EXPERIMENTAL_NOSET_CUDA_VISIBLE_DEVICES=1). Each worker uses the position of
its GPU in that list as its local rank. The safetensors loader now reads each
file on node-group rank 0, which is the rank that sends the broadcast.
2026-10-07 15:00:23 -07:00

252 lines
11 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# Adapt from https://github.com/vllm-project/vllm/blob/releases/v0.11.0/vllm/executor/ray_utils.py
from collections import defaultdict
import os
import time
from fastvideo.utils import get_ip
from fastvideo.fastvideo_args import FastVideoArgs
from fastvideo.worker.worker_base import WorkerWrapperBase
from fastvideo.logger import init_logger
logger = init_logger(__name__)
PG_WAIT_TIMEOUT = 1800
try:
import ray
from ray.util import placement_group_table
from ray.util.placement_group import PlacementGroup
try:
from ray._private.state import available_resources_per_node
except ImportError:
# Ray 2.9.x doesn't expose `available_resources_per_node`
from ray._private.state import state as _state
available_resources_per_node = _state._available_resources_per_node
class RayWorkerWrapper(WorkerWrapperBase):
"""Ray wrapper for fastvideo.worker.Worker, allowing Worker to be
lazily initialized after Ray sets CUDA_VISIBLE_DEVICES."""
def __init__(self, *args, **kwargs) -> None:
super().__init__(*args, **kwargs)
def get_node_ip(self) -> str:
return get_ip()
def get_node_and_gpu_ids(self) -> tuple[str, list[int]]:
from fastvideo.platforms import current_platform
node_id = ray.get_runtime_context().get_node_id()
device_key = current_platform.ray_device_key
if not device_key:
raise RuntimeError("current platform %s does not support ray.", current_platform.device_name)
gpu_ids = ray.get_runtime_context().get_accelerator_ids()[device_key]
return node_id, gpu_ids
def get_cuda_visible_devices(self) -> str | None:
"""Return the CUDA_VISIBLE_DEVICES this actor inherited from its raylet."""
return os.environ.get("CUDA_VISIBLE_DEVICES")
def override_env_vars(self, vars: dict[str, str]):
os.environ.update(vars)
ray_import_err = None
except ImportError as e:
ray = None
ray_import_err = str(e)
def assert_ray_available() -> None:
"""Raise an exception if Ray is not available."""
if ray is None:
raise ValueError(f"Failed to import Ray: {ray_import_err}."
"Please install Ray with `uv pip install ray`.")
def _verify_bundles(placement_group: "PlacementGroup", fastvideo_args: FastVideoArgs, device_str: str):
"""Verify a given placement group has bundles located in the right place.
There are 2 rules.
- Warn if all tensor parallel workers cannot fit in a single node.
- Fail if driver node is not included in a placement group.
"""
assert ray.is_initialized(), ("Ray is not initialized although distributed-executor-backend is ray.")
pg_data = placement_group_table(placement_group)
# bundle_idx -> node_id
bundle_to_node_ids = pg_data["bundles_to_node_id"]
# bundle_idx -> bundle (e.g., {"GPU": 1})
bundles = pg_data["bundles"]
# node_id -> List of bundle (e.g., {"GPU": 1})
node_id_to_bundle: dict[str, list[dict[str, float]]] = defaultdict(list)
for bundle_idx, node_id in bundle_to_node_ids.items():
node_id_to_bundle[node_id].append(bundles[bundle_idx])
driver_node_id = ray.get_runtime_context().get_node_id()
if driver_node_id not in node_id_to_bundle:
raise RuntimeError(f"driver node id {driver_node_id} is not included in a placement "
f"group {placement_group.id}. Node id -> bundles "
f"{node_id_to_bundle}. "
"You don't have enough GPUs available in a current node. Check "
"`ray status` and `ray list nodes` to see if you have available "
"GPUs in a node `{driver_node_id}` before starting an FastVideo engine.")
for node_id, bundles in node_id_to_bundle.items():
if len(bundles) < fastvideo_args.tp_size:
logger.warning(
"tensor_parallel_size=%d "
"is bigger than a reserved number of %ss (%d "
"%ss) in a node %s. Tensor parallel workers can be "
"spread out to 2+ nodes which can degrade the performance "
"unless you have fast interconnect across nodes, like "
"Infiniband. To resolve this issue, make sure you have more "
"than %d GPUs available at each node.", fastvideo_args.tp_size, device_str, len(bundles), device_str,
node_id, fastvideo_args.tp_size)
def _wait_until_pg_ready(current_placement_group: "PlacementGroup"):
"""Wait until a placement group is ready.
It prints the informative log messages if the placement group is
not created within time.
"""
# Wait until PG is ready - this will block until all
# requested resources are available, and will timeout
# if they cannot be provisioned.
placement_group_specs = current_placement_group.bundle_specs
s = time.time()
pg_ready_ref = current_placement_group.ready()
wait_interval = 10
while time.time() - s < PG_WAIT_TIMEOUT:
ready, _ = ray.wait([pg_ready_ref], timeout=wait_interval)
if len(ready) > 0:
break
# Exponential backoff for warning print.
wait_interval *= 2
logger.info(
"Waiting for creating a placement group of specs for "
"%d seconds. specs=%s. Check `ray status` and "
"`ray list nodes` to see if you have enough resources,"
" and make sure the IP addresses used by ray cluster"
" are the same as FASTVIDEO_HOST_IP environment variable"
" specified in each node if you are running on a multi-node.", int(time.time() - s), placement_group_specs)
try:
ray.get(pg_ready_ref, timeout=0)
except ray.exceptions.GetTimeoutError:
raise ValueError("Cannot provide a placement group of "
f"{placement_group_specs=} within {PG_WAIT_TIMEOUT} seconds. See "
"`ray status` and `ray list nodes` to make sure the cluster has "
"enough resources.") from None
def initialize_ray_cluster(
fastvideo_args: FastVideoArgs,
ray_address: str | None = None,
):
"""Initialize the distributed cluster with Ray.
it will connect to the Ray cluster and create a placement group
for the workers, which includes the specification of the resources
for each distributed worker.
Args:
parallel_config: The configurations for parallel execution.
ray_address: The address of the Ray cluster. If None, uses
the default Ray cluster address.
"""
assert_ray_available()
from fastvideo.platforms import current_platform
if ray.is_initialized():
logger.info("Ray is already initialized. Skipping Ray initialization.")
elif current_platform.is_rocm() or current_platform.is_xpu():
# Try to connect existing ray instance and create a new one if not found
try:
ray.init("auto")
except ConnectionError:
logger.warning("No existing RAY instance detected. "
"A new instance will be launched with current node resources.")
ray.init(address=ray_address, num_gpus=fastvideo_args.num_gpus, runtime_env=fastvideo_args.ray_runtime_env)
else:
ray.init(address=ray_address, runtime_env=fastvideo_args.ray_runtime_env)
device_str = current_platform.ray_device_key
if not device_str:
raise ValueError(f"current platform {current_platform.device_name} does not "
"support ray.")
# Create or get the placement group for worker processes
current_placement_group = fastvideo_args.ray_placement_group or ray.util.get_current_placement_group()
if current_placement_group:
logger.info("Using the existing placement group")
# We are in a placement group
bundles = current_placement_group.bundle_specs
# Verify that we can use the placement group.
device_bundles = 0
for bundle in bundles:
bundle_devices = bundle.get(device_str, 0)
if bundle_devices > 1:
raise ValueError("Placement group bundle cannot have more than 1 "
f"{device_str}.")
if bundle_devices:
device_bundles += 1
if fastvideo_args.num_gpus > device_bundles:
raise ValueError(f"The number of required {device_str}s exceeds the total "
f"number of available {device_str}s in the placement group. "
f"Required number of devices: {fastvideo_args.num_gpus}. "
f"Total number of devices: {device_bundles}.")
else:
logger.info("No current placement group found. "
"Creating a new placement group.")
num_devices_in_cluster = ray.cluster_resources().get(device_str, 0)
# Log a warning message and delay resource allocation failure response.
# Avoid immediate rejection to allow user-initiated placement group
# created and wait cluster to be ready
if fastvideo_args.num_gpus > num_devices_in_cluster:
logger.warning(
"The number of required %ss exceeds the total "
"number of available %ss in the placement group.", device_str, device_str)
# Create a new placement group
placement_group_specs: list[dict[str, float]] = ([{device_str: 1.0} for _ in range(fastvideo_args.num_gpus)])
# FastVideo engine is also a worker to execute model with an accelerator,
# so it requires to have the device in a current node. Check if
# the current node has at least one device.
current_ip = get_ip()
current_node_id = ray.get_runtime_context().get_node_id()
current_node_resource = available_resources_per_node()[current_node_id]
if current_node_resource.get(device_str, 0) < 1:
raise ValueError(f"Current node has no {device_str} available. "
f"{current_node_resource=}. FastVideo engine cannot start without "
f"{device_str}. Make sure you have at least 1 {device_str} "
f"available in a node {current_node_id=} {current_ip=}.")
# This way, at least bundle is required to be created in a current
# node.
placement_group_specs[0][f"node:{current_ip}"] = 0.001
# By default, Ray packs resources as much as possible.
current_placement_group = ray.util.placement_group(placement_group_specs, strategy="PACK")
_wait_until_pg_ready(current_placement_group)
assert current_placement_group is not None
_verify_bundles(current_placement_group, fastvideo_args, device_str)
# Set the placement group in the fastvideo args
fastvideo_args.ray_placement_group = current_placement_group
def is_in_ray_actor():
"""Check if we are in a Ray actor."""
try:
import ray
return (ray.is_initialized() and ray.get_runtime_context().get_actor_id() is not None)
except ImportError:
return False