无法通过 SSH 启动 dask 集群

Question

我正在尝试通过 SSH 启动一个 dask 集群，但遇到了类似以下的奇怪错误：

Exception in thread Thread-6:
Traceback (most recent call last):
  File "/home/localuser/miniconda3/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/home/localuser/miniconda3/lib/python3.6/threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "/home/localuser/miniconda3/lib/python3.6/site-packages/distributed/deploy/ssh.py", line 57, in async_ssh
    banner_timeout=20)  # Helps prevent timeouts when many concurrent ssh connections are opened.
  File "/home/localuser/miniconda3/lib/python3.6/site-packages/paramiko/client.py", line 329, in connect
    to_try = list(self._families_and_addresses(hostname, port))
  File "/home/localuser/miniconda3/lib/python3.6/site-packages/paramiko/client.py", line 200, in _families_and_addresses
    hostname, port, socket.AF_UNSPEC, socket.SOCK_STREAM)
  File "/home/localuser/miniconda3/lib/python3.6/socket.py", line 745, in getaddrinfo
    for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
socket.gaierror: [Errno -2] Name or service not known

我正在像这样启动集群：

$ dask-ssh --ssh-private-key ~/.ssh/cluster_id_rsa \
      --hostfile ~/dask-hosts.txt \
      --remote-python "~/miniconda3/bin/python3.6"

我的dask-hosts.txt 看起来像这样：

localuser@127.0.0.1
remoteuser@10.10.4.200
...
remoteuser@10.10.4.207

无论有没有 localhost 行，我都会遇到同样的错误。

我已经检查了 ssh 设置，我可以使用公钥设置登录到所有节点（密钥未加密，以避免出现解密提示）。我错过了什么？

Answer 1

该错误表明名称解析是罪魁祸首。这很可能是因为您的dask-hosts.txt 中包含用户名。根据its documentation，主机文件应该只包含主机名/IP 地址：

–hostfile PATH 带有主机名/IP 地址的文本文件

您可以使用--ssh-username 设置用户名（虽然只有一个）。