Source code for lightning_fabric.plugins.environments.slurm

# Copyright The Lightning AI team.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.

import logging
import os
import re
import shutil
import signal
import sys
from typing import Optional

from lightning_fabric.plugins.environments.cluster_environment import ClusterEnvironment
from lightning_fabric.utilities.imports import _IS_WINDOWS
from lightning_fabric.utilities.rank_zero import rank_zero_warn
from lightning_fabric.utilities.warnings import PossibleUserWarning

log = logging.getLogger(__name__)

[docs]class SLURMEnvironment(ClusterEnvironment): """Cluster environment for training on a cluster managed by SLURM. Args: auto_requeue: Whether automatic job resubmission is enabled or not. How and under which conditions a job gets rescheduled gets determined by the owner of this plugin. requeue_signal: The signal that SLURM will send to indicate that the job should be requeued. Defaults to SIGUSR1 on Unix. """ def __init__(self, auto_requeue: bool = True, requeue_signal: Optional[signal.Signals] = None) -> None: super().__init__() self.auto_requeue = auto_requeue if requeue_signal is None and not _IS_WINDOWS: requeue_signal = signal.SIGUSR1 self.requeue_signal = requeue_signal self._validate_srun_used() self._validate_srun_variables() @property def creates_processes_externally(self) -> bool: return True @property def main_address(self) -> str: nodelist = os.environ.get("SLURM_NODELIST", "") root_node = self.resolve_root_node_address(nodelist) os.environ["MASTER_ADDR"] = root_node log.debug(f"MASTER_ADDR: {os.environ['MASTER_ADDR']}") return root_node @property def main_port(self) -> int: # ----------------------- # SLURM JOB = PORT number # ----------------------- # this way every process knows what port to use job_id = os.environ.get("SLURM_JOB_ID") if job_id is not None: # use the last 4 numbers in the job id as the id default_port = job_id[-4:] # all ports should be in the 10k+ range default_port = int(default_port) + 15000 else: default_port = 12910 # ----------------------- # PORT NUMBER = MASTER_PORT # ----------------------- # in case the user passed it in if "MASTER_PORT" in os.environ: default_port = int(os.environ["MASTER_PORT"]) else: os.environ["MASTER_PORT"] = str(default_port) log.debug(f"MASTER_PORT: {os.environ['MASTER_PORT']}") return default_port
[docs] @staticmethod def detect() -> bool: """Returns ``True`` if the current process was launched on a SLURM cluster. It is possible to use the SLURM scheduler to request resources and then launch processes manually using a different environment. For this, the user can set the job name in SLURM to 'bash' or 'interactive' (srun --job- name=interactive). This will then avoid the detection of ``SLURMEnvironment`` and another environment can be detected automatically. """ SLURMEnvironment._validate_srun_used() return _is_srun_used()
@staticmethod def job_name() -> Optional[str]: return os.environ.get("SLURM_JOB_NAME") @staticmethod def job_id() -> Optional[int]: # in interactive mode, don't make logs use the same job id if _is_slurm_interactive_mode(): return None job_id = os.environ.get("SLURM_JOB_ID") if job_id is None: return None try: return int(job_id) except ValueError: return None
[docs] def world_size(self) -> int: return int(os.environ["SLURM_NTASKS"])
def set_world_size(self, size: int) -> None: log.debug("SLURMEnvironment.set_world_size was called, but setting world size is not allowed. Ignored.")
[docs] def global_rank(self) -> int: return int(os.environ["SLURM_PROCID"])
def set_global_rank(self, rank: int) -> None: log.debug("SLURMEnvironment.set_global_rank was called, but setting global rank is not allowed. Ignored.")
[docs] def local_rank(self) -> int: return int(os.environ["SLURM_LOCALID"])
[docs] def node_rank(self) -> int: return int(os.environ["SLURM_NODEID"])
[docs] @staticmethod def resolve_root_node_address(nodes: str) -> str: """The node selection format in SLURM supports several formats. This function selects the first host name from - a space-separated list of host names, e.g., 'host0 host1 host3' yields 'host0' as the root - a comma-separated list of host names, e.g., 'host0,host1,host3' yields 'host0' as the root - the range notation with brackets, e.g., 'host[5-9]' yields 'host5' as the root """ nodes = re.sub(r"\[(.*?)[,-].*\]", "\\1", nodes) # Take the first node of every node range nodes = re.sub(r"\[(.*?)\]", "\\1", nodes) # handle special case where node range is single number return nodes.split(" ")[0].split(",")[0]
@staticmethod def _validate_srun_used() -> None: """Checks if the `srun` command is available and used. Parallel jobs (multi-GPU, multi-node) in SLURM are launched by prepending `srun` in front of the Python command. Not doing so will result in processes hanging, which is a frequent user error. Lightning will emit a warning if `srun` is found but not used. """ if _IS_WINDOWS: return srun_exists = shutil.which("srun") is not None if srun_exists and not _is_srun_used(): hint = " ".join(["srun", os.path.basename(sys.executable), *sys.argv])[:64] rank_zero_warn( "The `srun` command is available on your system but is not used. HINT: If your intention is to run" f" Lightning on SLURM, prepend your python command with `srun` like so: {hint} ...", category=PossibleUserWarning, ) @staticmethod def _validate_srun_variables() -> None: """Checks for conflicting or incorrectly set variables set through `srun` and raises a useful error message. Right now, we only check for the most common user errors. See `the srun docs <>`_ for a complete list of supported srun variables. """ ntasks = int(os.environ.get("SLURM_NTASKS", "1")) if ntasks > 1 and "SLURM_NTASKS_PER_NODE" not in os.environ: raise RuntimeError( f"You set `--ntasks={ntasks}` in your SLURM bash script, but this variable is not supported." f" HINT: Use `--ntasks-per-node={ntasks}` instead." )
def _is_srun_used() -> bool: return "SLURM_NTASKS" in os.environ and not _is_slurm_interactive_mode() def _is_slurm_interactive_mode() -> bool: return SLURMEnvironment.job_name() in ("bash", "interactive")

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