dask 分布式，无法启动 worker

Question

在某些情况下，dask 集群似乎在重启时挂起

为了模拟这个我写了这个愚蠢的代码：

import contextlib2
from distributed import Client, LocalCluster

for i in xrange(100):
    print i
    with contextlib2.ExitStack() as es:
        cluster = LocalCluster(processes=True, n_workers=4)
        client = Client(cluster)
        es.callback(client.close)
        es.callback(es.callback(client.close))

这段代码永远不会完成循环我收到此错误

 raise_exc_info(self._exc_info)
  File "//anaconda/lib/python2.7/site-packages/tornado/gen.py", line 1141, in run
    yielded = self.gen.throw(*exc_info)
  File "//anaconda/lib/python2.7/site-packages/distributed/deploy/local.py", line 191, in _start
    yield [self._start_worker(**self.worker_kwargs) for i in range(n_workers)]
  File "//anaconda/lib/python2.7/site-packages/tornado/gen.py", line 1133, in run
    value = future.result()
  File "//anaconda/lib/python2.7/site-packages/tornado/concurrent.py", line 269, in result
    raise_exc_info(self._exc_info)
  File "//anaconda/lib/python2.7/site-packages/tornado/gen.py", line 883, in callback
    result_list.append(f.result())
  File "//anaconda/lib/python2.7/site-packages/tornado/concurrent.py", line 269, in result
    raise_exc_info(self._exc_info)
  File "//anaconda/lib/python2.7/site-packages/tornado/gen.py", line 1147, in run
    yielded = self.gen.send(value)
  File "//anaconda/lib/python2.7/site-packages/distributed/deploy/local.py", line 217, in _start_worker
    raise gen.TimeoutError("Worker failed to start")

我在 mac

上使用 dask 分布式 1.25.1 和 python 2.7 运行

Answer 1

这是 Dask 中的一个问题，而在 linux 上使用 python 2.7 时，启动新工作程序（多进程）的唯一方法是使用 fork

fork反过来可能会造成死锁详情查看 dask 打开的票 https://github.com/dask/distributed/issues/2446

dask 分布式，无法启动 worker

dask distributed , fail to start worker

dask

dask-distributed