X-Git-Url: https://wannabe.guru.org/gitweb/?a=blobdiff_plain;f=executors.py;h=47b4a89a88d693d535ed2e036c6288829505a005;hb=f2b4fe83f6fc853a68653bd5e3d9fe0648c3d105;hp=2f4cf8314fdb07c536c75999fa40ecd83781cb05;hpb=11eeb8574b7b4620ac6fd440cb251f8aa2458f5b;p=python_utils.git diff --git a/executors.py b/executors.py index 2f4cf83..47b4a89 100644 --- a/executors.py +++ b/executors.py @@ -15,28 +15,31 @@ import subprocess import threading import time from typing import Any, Callable, Dict, List, Optional, Set +import warnings import cloudpickle # type: ignore +from overrides import overrides from ansi import bg, fg, underline, reset import argparse_utils import config -from exec_utils import run_silently, cmd_in_background from decorator_utils import singleton -import histogram +from exec_utils import run_silently, cmd_in_background, cmd_with_timeout +import histogram as hist +from thread_utils import background_thread + logger = logging.getLogger(__name__) parser = config.add_commandline_args( - f"Executors ({__file__})", - "Args related to processing executors." + f"Executors ({__file__})", "Args related to processing executors." ) parser.add_argument( '--executors_threadpool_size', type=int, metavar='#THREADS', help='Number of threads in the default threadpool, leave unset for default', - default=None + default=None, ) parser.add_argument( '--executors_processpool_size', @@ -59,62 +62,63 @@ parser.add_argument( help='Maximum number of failures before giving up on a bundle', ) -RSYNC = 'rsync -q --no-motd -W --ignore-existing --timeout=60 --size-only -z' -SSH = 'ssh -oForwardX11=no' -HIST = histogram.SimpleHistogram( - histogram.SimpleHistogram.n_evenly_spaced_buckets( - int(0), int(500), 25 - ) -) - - -def run_local_bundle(fun, *args, **kwargs): - logger.debug(f"Running local bundle at {fun.__name__}") - start = time.time() - result = fun(*args, **kwargs) - end = time.time() - duration = end - start - logger.debug(f"{fun.__name__} finished; used {duration:.1f}s") - HIST.add_item(duration) - return result - - -def run_cloud_pickle(pickle): - fun, args, kwargs = cloudpickle.loads(pickle) - logger.debug(f"Running pickled bundle at {fun.__name__}") - start = time.time() - result = fun(*args, **kwargs) - end = time.time() - duration = end - start - logger.debug(f"{fun.__name__} finished; used {duration:.1f}s") - return result +SSH = '/usr/bin/ssh -oForwardX11=no' +SCP = '/usr/bin/scp -C' def make_cloud_pickle(fun, *args, **kwargs): - logger.info(f"Making cloudpickled bundle at {fun.__name__}") + logger.debug(f"Making cloudpickled bundle at {fun.__name__}") return cloudpickle.dumps((fun, args, kwargs)) class BaseExecutor(ABC): - def __init__(self): - pass + def __init__(self, *, title=''): + self.title = title + self.histogram = hist.SimpleHistogram( + hist.SimpleHistogram.n_evenly_spaced_buckets(int(0), int(500), 50) + ) + self.task_count = 0 @abstractmethod - def submit(self, - function: Callable, - *args, - **kwargs) -> fut.Future: + def submit(self, function: Callable, *args, **kwargs) -> fut.Future: pass @abstractmethod - def shutdown(self, - wait: bool = True) -> None: + def shutdown(self, wait: bool = True) -> None: pass + def shutdown_if_idle(self) -> bool: + """Shutdown the executor and return True if the executor is idle + (i.e. there are no pending or active tasks). Return False + otherwise. Note: this should only be called by the launcher + process. + + """ + if self.task_count == 0: + self.shutdown() + return True + return False + + def adjust_task_count(self, delta: int) -> None: + """Change the task count. Note: do not call this method from a + worker, it should only be called by the launcher process / + thread / machine. + + """ + self.task_count += delta + logger.debug(f'Adjusted task count by {delta} to {self.task_count}') + + def get_task_count(self) -> int: + """Change the task count. Note: do not call this method from a + worker, it should only be called by the launcher process / + thread / machine. + + """ + return self.task_count + class ThreadExecutor(BaseExecutor): - def __init__(self, - max_workers: Optional[int] = None): + def __init__(self, max_workers: Optional[int] = None): super().__init__() workers = None if max_workers is not None: @@ -123,38 +127,44 @@ class ThreadExecutor(BaseExecutor): workers = config.config['executors_threadpool_size'] logger.debug(f'Creating threadpool executor with {workers} workers') self._thread_pool_executor = fut.ThreadPoolExecutor( - max_workers=workers, - thread_name_prefix="thread_executor_helper" + max_workers=workers, thread_name_prefix="thread_executor_helper" ) - self.job_count = 0 + self.already_shutdown = False - def submit(self, - function: Callable, - *args, - **kwargs) -> fut.Future: - self.job_count += 1 - logger.debug( - f'Submitted work to threadpool; there are now {self.job_count} items.' - ) + # This is run on a different thread; do not adjust task count here. + def run_local_bundle(self, fun, *args, **kwargs): + logger.debug(f"Running local bundle at {fun.__name__}") + result = fun(*args, **kwargs) + return result + + @overrides + def submit(self, function: Callable, *args, **kwargs) -> fut.Future: + if self.already_shutdown: + raise Exception('Submitted work after shutdown.') + self.adjust_task_count(+1) newargs = [] newargs.append(function) for arg in args: newargs.append(arg) - return self._thread_pool_executor.submit( - run_local_bundle, - *newargs, - **kwargs) + start = time.time() + result = self._thread_pool_executor.submit( + self.run_local_bundle, *newargs, **kwargs + ) + result.add_done_callback(lambda _: self.histogram.add_item(time.time() - start)) + result.add_done_callback(lambda _: self.adjust_task_count(-1)) + return result - def shutdown(self, - wait = True) -> None: - logger.debug("Shutting down threadpool executor.") - print(HIST) - self._thread_pool_executor.shutdown(wait) + @overrides + def shutdown(self, wait=True) -> None: + if not self.already_shutdown: + logger.debug(f'Shutting down threadpool executor {self.title}') + print(self.histogram) + self._thread_pool_executor.shutdown(wait) + self.already_shutdown = True class ProcessExecutor(BaseExecutor): - def __init__(self, - max_workers=None): + def __init__(self, max_workers=None): super().__init__() workers = None if max_workers is not None: @@ -165,24 +175,45 @@ class ProcessExecutor(BaseExecutor): self._process_executor = fut.ProcessPoolExecutor( max_workers=workers, ) - self.job_count = 0 + self.already_shutdown = False + + # This is run in another process; do not adjust task count here. + def run_cloud_pickle(self, pickle): + fun, args, kwargs = cloudpickle.loads(pickle) + logger.debug(f"Running pickled bundle at {fun.__name__}") + result = fun(*args, **kwargs) + return result - def submit(self, - function: Callable, - *args, - **kwargs) -> fut.Future: - # Bundle it up before submitting because pickle sucks. + @overrides + def submit(self, function: Callable, *args, **kwargs) -> fut.Future: + if self.already_shutdown: + raise Exception('Submitted work after shutdown.') + start = time.time() + self.adjust_task_count(+1) pickle = make_cloud_pickle(function, *args, **kwargs) - self.job_count += 1 - logger.debug( - f'Submitting work to processpool executor; there are now {self.job_count} items.' - ) - return self._process_executor.submit(run_cloud_pickle, pickle) + result = self._process_executor.submit(self.run_cloud_pickle, pickle) + result.add_done_callback(lambda _: self.histogram.add_item(time.time() - start)) + result.add_done_callback(lambda _: self.adjust_task_count(-1)) + return result + @overrides def shutdown(self, wait=True) -> None: - logger.debug('Shutting down processpool executor') - print(HIST) - self._process_executor.shutdown(wait) + if not self.already_shutdown: + logger.debug(f'Shutting down processpool executor {self.title}') + self._process_executor.shutdown(wait) + print(self.histogram) + self.already_shutdown = True + + def __getstate__(self): + state = self.__dict__.copy() + state['_process_executor'] = None + return state + + +class RemoteExecutorException(Exception): + """Thrown when a bundle cannot be executed despite several retries.""" + + pass @dataclass @@ -203,6 +234,7 @@ class RemoteWorkerRecord: class BundleDetails: pickled_code: bytes uuid: str + fname: str worker: Optional[RemoteWorkerRecord] username: Optional[str] machine: Optional[str] @@ -212,78 +244,99 @@ class BundleDetails: pid: int start_ts: float end_ts: float - too_slow: bool - super_slow: bool + slower_than_local_p95: bool + slower_than_global_p95: bool src_bundle: BundleDetails is_cancelled: threading.Event was_cancelled: bool backup_bundles: Optional[List[BundleDetails]] failure_count: int + def __repr__(self): + uuid = self.uuid + if uuid[-9:-2] == '_backup': + uuid = uuid[:-9] + suffix = f'{uuid[-6:]}_b{self.uuid[-1:]}' + else: + suffix = uuid[-6:] + + colorz = [ + fg('violet red'), + fg('red'), + fg('orange'), + fg('peach orange'), + fg('yellow'), + fg('marigold yellow'), + fg('green yellow'), + fg('tea green'), + fg('cornflower blue'), + fg('turquoise blue'), + fg('tropical blue'), + fg('lavender purple'), + fg('medium purple'), + ] + c = colorz[int(uuid[-2:], 16) % len(colorz)] + fname = self.fname if self.fname is not None else 'nofname' + machine = self.machine if self.machine is not None else 'nomachine' + return f'{c}{suffix}/{fname}/{machine}{reset()}' + class RemoteExecutorStatus: def __init__(self, total_worker_count: int) -> None: - self.worker_count = total_worker_count + self.worker_count: int = total_worker_count self.known_workers: Set[RemoteWorkerRecord] = set() + self.start_time: float = time.time() self.start_per_bundle: Dict[str, float] = defaultdict(float) self.end_per_bundle: Dict[str, float] = defaultdict(float) self.finished_bundle_timings_per_worker: Dict[ - RemoteWorkerRecord, - List[float] - ] = {} - self.in_flight_bundles_by_worker: Dict[ - RemoteWorkerRecord, - Set[str] + RemoteWorkerRecord, List[float] ] = {} + self.in_flight_bundles_by_worker: Dict[RemoteWorkerRecord, Set[str]] = {} self.bundle_details_by_uuid: Dict[str, BundleDetails] = {} self.finished_bundle_timings: List[float] = [] self.last_periodic_dump: Optional[float] = None - self.total_bundles_submitted = 0 + self.total_bundles_submitted: int = 0 # Protects reads and modification using self. Also used # as a memory fence for modifications to bundle. - self.lock = threading.Lock() + self.lock: threading.Lock = threading.Lock() - def record_acquire_worker( - self, - worker: RemoteWorkerRecord, - uuid: str - ) -> None: + def record_acquire_worker(self, worker: RemoteWorkerRecord, uuid: str) -> None: with self.lock: - self.record_acquire_worker_already_locked( - worker, - uuid - ) + self.record_acquire_worker_already_locked(worker, uuid) def record_acquire_worker_already_locked( - self, - worker: RemoteWorkerRecord, - uuid: str + self, worker: RemoteWorkerRecord, uuid: str ) -> None: assert self.lock.locked() self.known_workers.add(worker) - self.start_per_bundle[uuid] = time.time() + self.start_per_bundle[uuid] = None x = self.in_flight_bundles_by_worker.get(worker, set()) x.add(uuid) self.in_flight_bundles_by_worker[worker] = x - def record_bundle_details( - self, - details: BundleDetails) -> None: + def record_bundle_details(self, details: BundleDetails) -> None: with self.lock: self.record_bundle_details_already_locked(details) - def record_bundle_details_already_locked( - self, - details: BundleDetails) -> None: + def record_bundle_details_already_locked(self, details: BundleDetails) -> None: assert self.lock.locked() self.bundle_details_by_uuid[details.uuid] = details + def record_release_worker( + self, + worker: RemoteWorkerRecord, + uuid: str, + was_cancelled: bool, + ) -> None: + with self.lock: + self.record_release_worker_already_locked(worker, uuid, was_cancelled) + def record_release_worker_already_locked( - self, - worker: RemoteWorkerRecord, - uuid: str, - was_cancelled: bool, + self, + worker: RemoteWorkerRecord, + uuid: str, + was_cancelled: bool, ) -> None: assert self.lock.locked() ts = time.time() @@ -296,6 +349,10 @@ class RemoteExecutorStatus: self.finished_bundle_timings_per_worker[worker] = x self.finished_bundle_timings.append(bundle_latency) + def record_processing_began(self, uuid: str): + with self.lock: + self.start_per_bundle[uuid] = time.time() + def total_in_flight(self) -> int: assert self.lock.locked() total_in_flight = 0 @@ -317,13 +374,14 @@ class RemoteExecutorStatus: if len(self.finished_bundle_timings) > 1: qall = numpy.quantile(self.finished_bundle_timings, [0.5, 0.95]) ret += ( - f'⏱=∀p50:{qall[0]:.1f}s, ∀p95:{qall[1]:.1f}s, ' + f'⏱=∀p50:{qall[0]:.1f}s, ∀p95:{qall[1]:.1f}s, total={ts-self.start_time:.1f}s, ' f'✅={total_finished}/{self.total_bundles_submitted}, ' f'💻n={total_in_flight}/{self.worker_count}\n' ) else: ret += ( - f' ✅={total_finished}/{self.total_bundles_submitted}, ' + f'⏱={ts-self.start_time:.1f}s, ' + f'✅={total_finished}/{self.total_bundles_submitted}, ' f'💻n={total_in_flight}/{self.worker_count}\n' ) @@ -343,31 +401,31 @@ class RemoteExecutorStatus: if in_flight > 0: ret += f' ...{in_flight} bundles currently in flight:\n' for bundle_uuid in self.in_flight_bundles_by_worker[worker]: - details = self.bundle_details_by_uuid.get( - bundle_uuid, - None - ) - pid = str(details.pid) if details is not None else "TBD" - sec = ts - self.start_per_bundle[bundle_uuid] - ret += f' (pid={pid}): {bundle_uuid} for {sec:.1f}s so far ' + details = self.bundle_details_by_uuid.get(bundle_uuid, None) + pid = str(details.pid) if (details and details.pid != 0) else "TBD" + if self.start_per_bundle[bundle_uuid] is not None: + sec = ts - self.start_per_bundle[bundle_uuid] + ret += f' (pid={pid}): {details} for {sec:.1f}s so far ' + else: + ret += f' {details} setting up / copying data...' + sec = 0.0 + if qworker is not None: if sec > qworker[1]: ret += f'{bg("red")}>💻p95{reset()} ' - elif sec > qworker[0]: - ret += f'{fg("red")}>💻p50{reset()} ' - if qall is not None: - if sec > qall[1] * 1.5: - ret += f'{bg("red")}!!!{reset()}' if details is not None: - logger.debug(f'Flagging {details.uuid} for another backup') - details.super_slow = True - elif sec > qall[1]: + details.slower_than_local_p95 = True + else: + if details is not None: + details.slower_than_local_p95 = False + + if qall is not None: + if sec > qall[1]: ret += f'{bg("red")}>∀p95{reset()} ' if details is not None: - logger.debug(f'Flagging {details.uuid} for a backup') - details.too_slow = True - elif sec > qall[0]: - ret += f'{fg("red")}>∀p50{reset()}' + details.slower_than_global_p95 = True + else: + details.slower_than_global_p95 = False ret += '\n' return ret @@ -375,17 +433,13 @@ class RemoteExecutorStatus: assert self.lock.locked() self.total_bundles_submitted = total_bundles_submitted ts = time.time() - if ( - self.last_periodic_dump is None - or ts - self.last_periodic_dump > 5.0 - ): + if self.last_periodic_dump is None or ts - self.last_periodic_dump > 5.0: print(self) self.last_periodic_dump = ts class RemoteWorkerSelectionPolicy(ABC): def register_worker_pool(self, workers): - random.seed() self.workers = workers @abstractmethod @@ -393,55 +447,61 @@ class RemoteWorkerSelectionPolicy(ABC): pass @abstractmethod - def acquire_worker( - self, - machine_to_avoid = None - ) -> Optional[RemoteWorkerRecord]: + def acquire_worker(self, machine_to_avoid=None) -> Optional[RemoteWorkerRecord]: pass class WeightedRandomRemoteWorkerSelectionPolicy(RemoteWorkerSelectionPolicy): + @overrides def is_worker_available(self) -> bool: for worker in self.workers: if worker.count > 0: return True return False - def acquire_worker( - self, - machine_to_avoid = None - ) -> Optional[RemoteWorkerRecord]: + @overrides + def acquire_worker(self, machine_to_avoid=None) -> Optional[RemoteWorkerRecord]: grabbag = [] for worker in self.workers: - for x in range(0, worker.count): - for y in range(0, worker.weight): - grabbag.append(worker) - - for _ in range(0, 5): - random.shuffle(grabbag) - worker = grabbag[0] - if worker.machine != machine_to_avoid or _ > 2: + if worker.machine != machine_to_avoid: if worker.count > 0: - worker.count -= 1 - logger.debug(f'Selected worker {worker}') - return worker - logger.warning("Couldn't find a worker; go fish.") - return None + for _ in range(worker.count * worker.weight): + grabbag.append(worker) + + if len(grabbag) == 0: + logger.debug( + f'There are no available workers that avoid {machine_to_avoid}...' + ) + for worker in self.workers: + if worker.count > 0: + for _ in range(worker.count * worker.weight): + grabbag.append(worker) + + if len(grabbag) == 0: + logger.warning('There are no available workers?!') + return None + + worker = random.sample(grabbag, 1)[0] + assert worker.count > 0 + worker.count -= 1 + logger.debug(f'Chose worker {worker}') + return worker class RoundRobinRemoteWorkerSelectionPolicy(RemoteWorkerSelectionPolicy): def __init__(self) -> None: self.index = 0 + @overrides def is_worker_available(self) -> bool: for worker in self.workers: if worker.count > 0: return True return False + @overrides def acquire_worker( - self, - machine_to_avoid: str = None + self, machine_to_avoid: str = None ) -> Optional[RemoteWorkerRecord]: x = self.index while True: @@ -458,48 +518,178 @@ class RoundRobinRemoteWorkerSelectionPolicy(RemoteWorkerSelectionPolicy): if x >= len(self.workers): x = 0 if x == self.index: - logger.warning("Couldn't find a worker; go fish.") + msg = 'Unexpectedly could not find a worker, retrying...' + logger.warning(msg) return None class RemoteExecutor(BaseExecutor): - def __init__(self, - workers: List[RemoteWorkerRecord], - policy: RemoteWorkerSelectionPolicy) -> None: + def __init__( + self, + workers: List[RemoteWorkerRecord], + policy: RemoteWorkerSelectionPolicy, + ) -> None: super().__init__() self.workers = workers + self.policy = policy self.worker_count = 0 for worker in self.workers: self.worker_count += worker.count if self.worker_count <= 0: msg = f"We need somewhere to schedule work; count was {self.worker_count}" logger.critical(msg) - raise Exception(msg) - self.policy = policy + raise RemoteExecutorException(msg) self.policy.register_worker_pool(self.workers) self.cv = threading.Condition() + logger.debug( + f'Creating {self.worker_count} local threads, one per remote worker.' + ) self._helper_executor = fut.ThreadPoolExecutor( thread_name_prefix="remote_executor_helper", max_workers=self.worker_count, ) self.status = RemoteExecutorStatus(self.worker_count) self.total_bundles_submitted = 0 - logger.debug( - f'Creating remote processpool with {self.worker_count} remote endpoints.' - ) + self.backup_lock = threading.Lock() + self.last_backup = None + ( + self.heartbeat_thread, + self.heartbeat_stop_event, + ) = self.run_periodic_heartbeat() + self.already_shutdown = False + + @background_thread + def run_periodic_heartbeat(self, stop_event: threading.Event) -> None: + while not stop_event.is_set(): + time.sleep(5.0) + logger.debug('Running periodic heartbeat code...') + self.heartbeat() + logger.debug('Periodic heartbeat thread shutting down.') + + def heartbeat(self) -> None: + # Note: this is invoked on a background thread, not an + # executor thread. Be careful what you do with it b/c it + # needs to get back and dump status again periodically. + with self.status.lock: + self.status.periodic_dump(self.total_bundles_submitted) + + # Look for bundles to reschedule via executor.submit + if config.config['executors_schedule_remote_backups']: + self.maybe_schedule_backup_bundles() + + def maybe_schedule_backup_bundles(self): + assert self.status.lock.locked() + num_done = len(self.status.finished_bundle_timings) + num_idle_workers = self.worker_count - self.task_count + now = time.time() + if ( + num_done > 2 + and num_idle_workers > 1 + and (self.last_backup is None or (now - self.last_backup > 9.0)) + and self.backup_lock.acquire(blocking=False) + ): + try: + assert self.backup_lock.locked() + + bundle_to_backup = None + best_score = None + for ( + worker, + bundle_uuids, + ) in self.status.in_flight_bundles_by_worker.items(): + + # Prefer to schedule backups of bundles running on + # slower machines. + base_score = 0 + for record in self.workers: + if worker.machine == record.machine: + base_score = float(record.weight) + base_score = 1.0 / base_score + base_score *= 200.0 + base_score = int(base_score) + break + + for uuid in bundle_uuids: + bundle = self.status.bundle_details_by_uuid.get(uuid, None) + if ( + bundle is not None + and bundle.src_bundle is None + and bundle.backup_bundles is not None + ): + score = base_score + + # Schedule backups of bundles running + # longer; especially those that are + # unexpectedly slow. + start_ts = self.status.start_per_bundle[uuid] + if start_ts is not None: + runtime = now - start_ts + score += runtime + logger.debug( + f'score[{bundle}] => {score} # latency boost' + ) + + if bundle.slower_than_local_p95: + score += runtime / 2 + logger.debug( + f'score[{bundle}] => {score} # >worker p95' + ) + + if bundle.slower_than_global_p95: + score += runtime / 4 + logger.debug( + f'score[{bundle}] => {score} # >global p95' + ) + + # Prefer backups of bundles that don't + # have backups already. + backup_count = len(bundle.backup_bundles) + if backup_count == 0: + score *= 2 + elif backup_count == 1: + score /= 2 + elif backup_count == 2: + score /= 8 + else: + score = 0 + logger.debug( + f'score[{bundle}] => {score} # {backup_count} dup backup factor' + ) + + if score != 0 and ( + best_score is None or score > best_score + ): + bundle_to_backup = bundle + assert bundle is not None + assert bundle.backup_bundles is not None + assert bundle.src_bundle is None + best_score = score + + # Note: this is all still happening on the heartbeat + # runner thread. That's ok because + # schedule_backup_for_bundle uses the executor to + # submit the bundle again which will cause it to be + # picked up by a worker thread and allow this thread + # to return to run future heartbeats. + if bundle_to_backup is not None: + self.last_backup = now + logger.info( + f'=====> SCHEDULING BACKUP {bundle_to_backup} (score={best_score:.1f}) <=====' + ) + self.schedule_backup_for_bundle(bundle_to_backup) + finally: + self.backup_lock.release() def is_worker_available(self) -> bool: return self.policy.is_worker_available() def acquire_worker( - self, - machine_to_avoid: str = None + self, machine_to_avoid: str = None ) -> Optional[RemoteWorkerRecord]: return self.policy.acquire_worker(machine_to_avoid) def find_available_worker_or_block( - self, - machine_to_avoid: str = None + self, machine_to_avoid: str = None ) -> RemoteWorkerRecord: with self.cv: while not self.is_worker_available(): @@ -511,49 +701,19 @@ class RemoteExecutor(BaseExecutor): logger.critical(msg) raise Exception(msg) - def release_worker(self, worker: RemoteWorkerRecord) -> None: + def release_worker(self, bundle: BundleDetails, *, was_cancelled=True) -> None: + worker = bundle.worker + assert worker is not None logger.debug(f'Released worker {worker}') + self.status.record_release_worker( + worker, + bundle.uuid, + was_cancelled, + ) with self.cv: worker.count += 1 self.cv.notify() - - def heartbeat(self) -> None: - with self.status.lock: - # Regular progress report - self.status.periodic_dump(self.total_bundles_submitted) - - # Look for bundles to reschedule - if len(self.status.finished_bundle_timings) > 7: - for worker, bundle_uuids in self.status.in_flight_bundles_by_worker.items(): - for uuid in bundle_uuids: - bundle = self.status.bundle_details_by_uuid.get(uuid, None) - if ( - bundle is not None and - bundle.too_slow and - bundle.src_bundle is None and - config.config['executors_schedule_remote_backups'] - ): - self.consider_backup_for_bundle(bundle) - - def consider_backup_for_bundle(self, bundle: BundleDetails) -> None: - assert self.status.lock.locked() - if ( - bundle.too_slow - and len(bundle.backup_bundles) == 0 # one backup per - ): - msg = f"*** Rescheduling {bundle.pid}/{bundle.uuid} ***" - logger.debug(msg) - self.schedule_backup_for_bundle(bundle) - return - elif ( - bundle.super_slow - and len(bundle.backup_bundles) < 2 # two backups in dire situations - and self.status.total_idle() > 4 - ): - msg = f"*** Rescheduling {bundle.pid}/{bundle.uuid} ***" - logger.debug(msg) - self.schedule_backup_for_bundle(bundle) - return + self.adjust_task_count(-1) def check_if_cancelled(self, bundle: BundleDetails) -> bool: with self.status.lock: @@ -563,80 +723,173 @@ class RemoteExecutor(BaseExecutor): return True return False - def launch(self, bundle: BundleDetails) -> Any: + def launch(self, bundle: BundleDetails, override_avoid_machine=None) -> Any: """Find a worker for bundle or block until one is available.""" + self.adjust_task_count(+1) uuid = bundle.uuid hostname = bundle.hostname - avoid_machine = None + avoid_machine = override_avoid_machine + is_original = bundle.src_bundle is None # Try not to schedule a backup on the same host as the original. - if bundle.src_bundle is not None: + if avoid_machine is None and bundle.src_bundle is not None: avoid_machine = bundle.src_bundle.machine worker = None while worker is None: worker = self.find_available_worker_or_block(avoid_machine) + assert worker + + # Ok, found a worker. bundle.worker = worker machine = bundle.machine = worker.machine username = bundle.username = worker.username self.status.record_acquire_worker(worker, uuid) - logger.debug(f'Running bundle {uuid} on {worker}...') + logger.debug(f'{bundle}: Running bundle on {worker}...') # Before we do any work, make sure the bundle is still viable. + # It may have been some time between when it was submitted and + # now due to lack of worker availability and someone else may + # have already finished it. if self.check_if_cancelled(bundle): try: - return self.post_launch_work(bundle) + return self.process_work_result(bundle) except Exception as e: - logger.exception(e) - logger.info(f"Bundle {uuid} seems to have failed?!") - if bundle.failure_count < config.config['executors_max_bundle_failures']: - return self.launch(bundle) + logger.warning( + f'{bundle}: bundle says it\'s cancelled upfront but no results?!' + ) + self.release_worker(bundle) + if is_original: + # Weird. We are the original owner of this + # bundle. For it to have been cancelled, a backup + # must have already started and completed before + # we even for started. Moreover, the backup says + # it is done but we can't find the results it + # should have copied over. Reschedule the whole + # thing. + logger.exception(e) + logger.error( + f'{bundle}: We are the original owner thread and yet there are ' + + 'no results for this bundle. This is unexpected and bad.' + ) + return self.emergency_retry_nasty_bundle(bundle) else: - logger.info(f"Bundle {uuid} is poison, giving up on it.") + # Expected(?). We're a backup and our bundle is + # cancelled before we even got started. Something + # went bad in process_work_result (I acutually don't + # see what?) but probably not worth worrying + # about. Let the original thread worry about + # either finding the results or complaining about + # it. return None - # Send input to machine if it's not local. + # Send input code / data to worker machine if it's not local. if hostname not in machine: - cmd = f'{RSYNC} {bundle.code_file} {username}@{machine}:{bundle.code_file}' - logger.info(f"Copying work to {worker} via {cmd}") - run_silently(cmd) - - # Do it. - cmd = (f'{SSH} {bundle.username}@{bundle.machine} ' - f'"source remote-execution/bin/activate &&' - f' /home/scott/lib/python_modules/remote_worker.py' - f' --code_file {bundle.code_file} --result_file {bundle.result_file}"') + try: + cmd = ( + f'{SCP} {bundle.code_file} {username}@{machine}:{bundle.code_file}' + ) + start_ts = time.time() + logger.info(f"{bundle}: Copying work to {worker} via {cmd}.") + run_silently(cmd) + xfer_latency = time.time() - start_ts + logger.debug(f"{bundle}: Copying to {worker} took {xfer_latency:.1f}s.") + except Exception as e: + self.release_worker(bundle) + if is_original: + # Weird. We tried to copy the code to the worker and it failed... + # And we're the original bundle. We have to retry. + logger.exception(e) + logger.error( + f"{bundle}: Failed to send instructions to the worker machine?! " + + "This is not expected; we\'re the original bundle so this shouldn\'t " + + "be a race condition. Attempting an emergency retry..." + ) + return self.emergency_retry_nasty_bundle(bundle) + else: + # This is actually expected; we're a backup. + # There's a race condition where someone else + # already finished the work and removed the source + # code file before we could copy it. No biggie. + msg = f'{bundle}: Failed to send instructions to the worker machine... ' + msg += 'We\'re a backup and this may be caused by the original (or some ' + msg += 'other backup) already finishing this work. Ignoring this.' + logger.warning(msg) + return None + + # Kick off the work. Note that if this fails we let + # wait_for_process deal with it. + self.status.record_processing_began(uuid) + cmd = ( + f'{SSH} {bundle.username}@{bundle.machine} ' + f'"source py38-venv/bin/activate &&' + f' /home/scott/lib/python_modules/remote_worker.py' + f' --code_file {bundle.code_file} --result_file {bundle.result_file}"' + ) + logger.debug(f'{bundle}: Executing {cmd} in the background to kick off work...') p = cmd_in_background(cmd, silent=True) - bundle.pid = pid = p.pid - logger.info(f"Running {cmd} in the background as process {pid}") + bundle.pid = p.pid + logger.debug( + f'{bundle}: Local ssh process pid={p.pid}; remote worker is {machine}.' + ) + return self.wait_for_process(p, bundle, 0) + + def wait_for_process( + self, p: subprocess.Popen, bundle: BundleDetails, depth: int + ) -> Any: + machine = bundle.machine + pid = p.pid + if depth > 3: + logger.error( + f"I've gotten repeated errors waiting on this bundle; giving up on pid={pid}." + ) + p.terminate() + self.release_worker(bundle) + return self.emergency_retry_nasty_bundle(bundle) + # Spin until either the ssh job we scheduled finishes the + # bundle or some backup worker signals that they finished it + # before we could. while True: try: - p.wait(timeout=0.5) + p.wait(timeout=0.25) except subprocess.TimeoutExpired: - self.heartbeat() - - # Both source and backup bundles can be cancelled by - # the other depending on which finishes first. if self.check_if_cancelled(bundle): - p.terminate() + logger.info( + f'{bundle}: looks like another worker finished bundle...' + ) break else: - logger.debug( - f"{pid}/{bundle.uuid} has finished its work normally." - ) + logger.info(f"{bundle}: pid {pid} ({machine}) is finished!") + p = None break + # If we get here we believe the bundle is done; either the ssh + # subprocess finished (hopefully successfully) or we noticed + # that some other worker seems to have completed the bundle + # and we're bailing out. try: - return self.post_launch_work(bundle) + ret = self.process_work_result(bundle) + if ret is not None and p is not None: + p.terminate() + return ret + + # Something went wrong; e.g. we could not copy the results + # back, cleanup after ourselves on the remote machine, or + # unpickle the results we got from the remove machine. If we + # still have an active ssh subprocess, keep waiting on it. + # Otherwise, time for an emergency reschedule. except Exception as e: logger.exception(e) - logger.info(f"Bundle {uuid} seems to have failed?!") - if bundle.failure_count < config.config['executors_max_bundle_failures']: - return self.launch(bundle) - logger.info(f"Bundle {uuid} is poison, giving up on it.") - return None + logger.error(f'{bundle}: Something unexpected just happened...') + if p is not None: + msg = f"{bundle}: Failed to wrap up \"done\" bundle, re-waiting on active ssh." + logger.warning(msg) + return self.wait_for_process(p, bundle, depth + 1) + else: + self.release_worker(bundle) + return self.emergency_retry_nasty_bundle(bundle) - def post_launch_work(self, bundle: BundleDetails) -> Any: + def process_work_result(self, bundle: BundleDetails) -> Any: with self.status.lock: is_original = bundle.src_bundle is None was_cancelled = bundle.was_cancelled @@ -648,53 +901,60 @@ class RemoteExecutor(BaseExecutor): # Whether original or backup, if we finished first we must # fetch the results if the computation happened on a # remote machine. + bundle.end_ts = time.time() if not was_cancelled: assert bundle.machine is not None if bundle.hostname not in bundle.machine: - cmd = f'{RSYNC} {username}@{machine}:{result_file} {result_file} 2>/dev/null' + cmd = f'{SCP} {username}@{machine}:{result_file} {result_file} 2>/dev/null' logger.info( - f"Fetching results from {username}@{machine} via {cmd}" + f"{bundle}: Fetching results back from {username}@{machine} via {cmd}" ) - try: - run_silently(cmd) - except subprocess.CalledProcessError: - pass - run_silently(f'{SSH} {username}@{machine}' - f' "/bin/rm -f {code_file} {result_file}"') - bundle.end_ts = time.time() - assert bundle.worker is not None - self.status.record_release_worker_already_locked( - bundle.worker, - bundle.uuid, - was_cancelled - ) - if not was_cancelled: - dur = bundle.end_ts - bundle.start_ts - HIST.add_item(dur) - # Original or not, the results should be back on the local - # machine. Are they? - if not os.path.exists(result_file): - msg = f'{result_file} unexpectedly missing, wtf?!' - logger.critical(msg) - bundle.failure_count += 1 - self.release_worker(bundle.worker) - raise Exception(msg) + # If either of these throw they are handled in + # wait_for_process. + attempts = 0 + while True: + try: + run_silently(cmd) + except Exception as e: + attempts += 1 + if attempts >= 3: + raise (e) + else: + break + + run_silently( + f'{SSH} {username}@{machine}' + f' "/bin/rm -f {code_file} {result_file}"' + ) + logger.debug( + f'Fetching results back took {time.time() - bundle.end_ts:.1f}s.' + ) + dur = bundle.end_ts - bundle.start_ts + self.histogram.add_item(dur) # Only the original worker should unpickle the file contents - # though since it's the only one whose result matters. + # though since it's the only one whose result matters. The + # original is also the only job that may delete result_file + # from disk. Note that the original may have been cancelled + # if one of the backups finished first; it still must read the + # result from disk. if is_original: - logger.debug(f"Unpickling {result_file}.") + logger.debug(f"{bundle}: Unpickling {result_file}.") try: - with open(f'{result_file}', 'rb') as rb: + with open(result_file, 'rb') as rb: serialized = rb.read() result = cloudpickle.loads(serialized) except Exception as e: - msg = f'Failed to load {result_file}' + logger.exception(e) + msg = f'Failed to load {result_file}... this is bad news.' logger.critical(msg) - bundle.failure_count += 1 - self.release_worker(bundle.worker) + self.release_worker(bundle) + + # Re-raise the exception; the code in wait_for_process may + # decide to emergency_retry_nasty_bundle here. raise Exception(e) + logger.debug(f'Removing local (master) {code_file} and {result_file}.') os.remove(f'{result_file}') os.remove(f'{code_file}') @@ -705,31 +965,31 @@ class RemoteExecutor(BaseExecutor): if bundle.backup_bundles is not None: for backup in bundle.backup_bundles: logger.debug( - f'Notifying backup {backup.uuid} that it is cancelled' + f'{bundle}: Notifying backup {backup.uuid} that it\'s cancelled' ) backup.is_cancelled.set() - # This is a backup. + # This is a backup job and, by now, we have already fetched + # the bundle results. else: # Backup results don't matter, they just need to leave the - # result file in the right place for their original to - # read later. + # result file in the right place for their originals to + # read/unpickle later. result = None # Tell the original to stop if we finished first. if not was_cancelled: logger.debug( - f'Notifying original {bundle.src_bundle.uuid} that it is cancelled' + f'{bundle}: Notifying original {bundle.src_bundle.uuid} we beat them to it.' ) bundle.src_bundle.is_cancelled.set() - - assert bundle.worker is not None - self.release_worker(bundle.worker) + self.release_worker(bundle, was_cancelled=was_cancelled) return result - def create_original_bundle(self, pickle): + def create_original_bundle(self, pickle, fname: str): from string_utils import generate_uuid - uuid = generate_uuid(as_hex=True) + + uuid = generate_uuid(omit_dashes=True) code_file = f'/tmp/{uuid}.code.bin' result_file = f'/tmp/{uuid}.result.bin' @@ -738,27 +998,28 @@ class RemoteExecutor(BaseExecutor): wb.write(pickle) bundle = BundleDetails( - pickled_code = pickle, - uuid = uuid, - worker = None, - username = None, - machine = None, - hostname = platform.node(), - code_file = code_file, - result_file = result_file, - pid = 0, - start_ts = time.time(), - end_ts = 0.0, - too_slow = False, - super_slow = False, - src_bundle = None, - is_cancelled = threading.Event(), - was_cancelled = False, - backup_bundles = [], - failure_count = 0, + pickled_code=pickle, + uuid=uuid, + fname=fname, + worker=None, + username=None, + machine=None, + hostname=platform.node(), + code_file=code_file, + result_file=result_file, + pid=0, + start_ts=time.time(), + end_ts=0.0, + slower_than_local_p95=False, + slower_than_global_p95=False, + src_bundle=None, + is_cancelled=threading.Event(), + was_cancelled=False, + backup_bundles=[], + failure_count=0, ) self.status.record_bundle_details(bundle) - logger.debug(f'Created original bundle {uuid}') + logger.debug(f'{bundle}: Created an original bundle') return bundle def create_backup_bundle(self, src_bundle: BundleDetails): @@ -767,36 +1028,37 @@ class RemoteExecutor(BaseExecutor): uuid = src_bundle.uuid + f'_backup#{n}' backup_bundle = BundleDetails( - pickled_code = src_bundle.pickled_code, - uuid = uuid, - worker = None, - username = None, - machine = None, - hostname = src_bundle.hostname, - code_file = src_bundle.code_file, - result_file = src_bundle.result_file, - pid = 0, - start_ts = time.time(), - end_ts = 0.0, - too_slow = False, - super_slow = False, - src_bundle = src_bundle, - is_cancelled = threading.Event(), - was_cancelled = False, - backup_bundles = None, # backup backups not allowed - failure_count = 0, + pickled_code=src_bundle.pickled_code, + uuid=uuid, + fname=src_bundle.fname, + worker=None, + username=None, + machine=None, + hostname=src_bundle.hostname, + code_file=src_bundle.code_file, + result_file=src_bundle.result_file, + pid=0, + start_ts=time.time(), + end_ts=0.0, + slower_than_local_p95=False, + slower_than_global_p95=False, + src_bundle=src_bundle, + is_cancelled=threading.Event(), + was_cancelled=False, + backup_bundles=None, # backup backups not allowed + failure_count=0, ) src_bundle.backup_bundles.append(backup_bundle) self.status.record_bundle_details_already_locked(backup_bundle) - logger.debug(f'Created backup bundle {uuid}') + logger.debug(f'{backup_bundle}: Created a backup bundle') return backup_bundle - def schedule_backup_for_bundle(self, - src_bundle: BundleDetails): + def schedule_backup_for_bundle(self, src_bundle: BundleDetails): assert self.status.lock.locked() + assert src_bundle is not None backup_bundle = self.create_backup_bundle(src_bundle) logger.debug( - f'Scheduling backup bundle {backup_bundle.uuid} for execution' + f'{backup_bundle.uuid}/{backup_bundle.fname}: Scheduling backup for execution...' ) self._helper_executor.submit(self.launch, backup_bundle) @@ -804,21 +1066,55 @@ class RemoteExecutor(BaseExecutor): # they will move the result_file to this machine and let # the original pick them up and unpickle them. - def submit(self, - function: Callable, - *args, - **kwargs) -> fut.Future: + def emergency_retry_nasty_bundle(self, bundle: BundleDetails) -> fut.Future: + is_original = bundle.src_bundle is None + bundle.worker = None + avoid_last_machine = bundle.machine + bundle.machine = None + bundle.username = None + bundle.failure_count += 1 + if is_original: + retry_limit = 3 + else: + retry_limit = 2 + + if bundle.failure_count > retry_limit: + logger.error( + f'{bundle}: Tried this bundle too many times already ({retry_limit}x); giving up.' + ) + if is_original: + raise RemoteExecutorException( + f'{bundle}: This bundle can\'t be completed despite several backups and retries' + ) + else: + logger.error( + f'{bundle}: At least it\'s only a backup; better luck with the others.' + ) + return None + else: + msg = f'>>> Emergency rescheduling {bundle} because of unexected errors (wtf?!) <<<' + logger.warning(msg) + warnings.warn(msg) + return self.launch(bundle, avoid_last_machine) + + @overrides + def submit(self, function: Callable, *args, **kwargs) -> fut.Future: + if self.already_shutdown: + raise Exception('Submitted work after shutdown.') pickle = make_cloud_pickle(function, *args, **kwargs) - bundle = self.create_original_bundle(pickle) + bundle = self.create_original_bundle(pickle, function.__name__) self.total_bundles_submitted += 1 - logger.debug( - f'Submitted work to remote executor; {self.total_bundles_submitted} items now submitted' - ) return self._helper_executor.submit(self.launch, bundle) + @overrides def shutdown(self, wait=True) -> None: - self._helper_executor.shutdown(wait) - print(HIST) + if not self.already_shutdown: + logging.debug(f'Shutting down RemoteExecutor {self.title}') + self.heartbeat_stop_event.set() + self.heartbeat_thread.join() + self._helper_executor.shutdown(wait) + print(self.histogram) + self.already_shutdown = True @singleton @@ -829,12 +1125,14 @@ class DefaultExecutors(object): self.remote_executor: Optional[RemoteExecutor] = None def ping(self, host) -> bool: - command = ['ping', '-c', '1', host] - return subprocess.call( - command, - stdout=subprocess.DEVNULL, - stderr=subprocess.DEVNULL, - ) == 0 + logger.debug(f'RUN> ping -c 1 {host}') + try: + x = cmd_with_timeout( + f'ping -c 1 {host} >/dev/null 2>/dev/null', timeout_seconds=1.0 + ) + return x == 0 + except Exception: + return False def thread_pool(self) -> ThreadExecutor: if self.thread_executor is None: @@ -848,62 +1146,77 @@ class DefaultExecutors(object): def remote_pool(self) -> RemoteExecutor: if self.remote_executor is None: + logger.info('Looking for some helper machines...') pool: List[RemoteWorkerRecord] = [] if self.ping('cheetah.house'): + logger.info('Found cheetah.house') pool.append( RemoteWorkerRecord( - username = 'scott', - machine = 'cheetah.house', - weight = 12, - count = 4, + username='scott', + machine='cheetah.house', + weight=30, + count=6, ), ) - if self.ping('video.house'): + if self.ping('meerkat.cabin'): + logger.info('Found meerkat.cabin') pool.append( RemoteWorkerRecord( - username = 'scott', - machine = 'video.house', - weight = 1, - count = 4, + username='scott', + machine='meerkat.cabin', + weight=12, + count=2, ), ) if self.ping('wannabe.house'): + logger.info('Found wannabe.house') pool.append( RemoteWorkerRecord( - username = 'scott', - machine = 'wannabe.house', - weight = 2, - count = 4, + username='scott', + machine='wannabe.house', + weight=25, + count=10, ), ) - if self.ping('meerkat.cabin'): + if self.ping('puma.cabin'): + logger.info('Found puma.cabin') pool.append( RemoteWorkerRecord( - username = 'scott', - machine = 'meerkat.cabin', - weight = 7, - count = 2, + username='scott', + machine='puma.cabin', + weight=30, + count=6, ), ) if self.ping('backup.house'): + logger.info('Found backup.house') pool.append( RemoteWorkerRecord( - username = 'scott', - machine = 'backup.house', - weight = 1, - count = 4, - ), - ) - if self.ping('puma.cabin'): - pool.append( - RemoteWorkerRecord( - username = 'scott', - machine = 'puma.cabin', - weight = 12, - count = 4, + username='scott', + machine='backup.house', + weight=8, + count=2, ), ) + + # The controller machine has a lot to do; go easy on it. + for record in pool: + if record.machine == platform.node() and record.count > 1: + logger.info(f'Reducing workload for {record.machine}.') + record.count = 1 + policy = WeightedRandomRemoteWorkerSelectionPolicy() policy.register_worker_pool(pool) self.remote_executor = RemoteExecutor(pool, policy) return self.remote_executor + + def shutdown(self) -> None: + if self.thread_executor is not None: + self.thread_executor.shutdown() + self.thread_executor = None + if self.process_executor is not None: + self.process_executor.shutdown() + self.process_executor = None + if self.remote_executor is not None: + self.remote_executor.shutdown() + self.remote_executor = None