AirflowException：Celery 命令失败 - 记录的主机名与此实例的主机名不匹配

Question

我在两个 AWS EC2 实例上运行的集群环境中运行 Airflow。一份给主人，一份给工人。不过，工作节点在运行“$airflowworker”时会定期抛出此错误：

[2018-08-09 16:15:43,553] {jobs.py:2574} WARNING - The recorded hostname ip-1.2.3.4 does not match this instance's hostname ip-1.2.3.4.eco.tanonprod.comanyname.io
Traceback (most recent call last):
  File "/usr/bin/airflow", line 27, in <module>
    args.func(args)
  File "/usr/local/lib/python3.6/site-packages/airflow/bin/cli.py", line 387, in run
    run_job.run()
  File "/usr/local/lib/python3.6/site-packages/airflow/jobs.py", line 198, in run
    self._execute()
  File "/usr/local/lib/python3.6/site-packages/airflow/jobs.py", line 2527, in _execute
    self.heartbeat()
  File "/usr/local/lib/python3.6/site-packages/airflow/jobs.py", line 182, in heartbeat
    self.heartbeat_callback(session=session)
  File "/usr/local/lib/python3.6/site-packages/airflow/utils/db.py", line 50, in wrapper
    result = func(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/airflow/jobs.py", line 2575, in heartbeat_callback
    raise AirflowException("Hostname of job runner does not match")
airflow.exceptions.AirflowException: Hostname of job runner does not match
[2018-08-09 16:15:43,671] {celery_executor.py:54} ERROR - Command 'airflow run arl_source_emr_test_dag runEmrStep2WaiterTask 2018-08-07T00:00:00 --local -sd /var/lib/airflow/dags/arl_source_emr_test_dag.py' returned non-zero exit status 1.
[2018-08-09 16:15:43,681: ERROR/ForkPoolWorker-30] Task airflow.executors.celery_executor.execute_command[875a4da9-582e-4c10-92aa-5407f3b46d5f] raised unexpected: AirflowException('Celery command failed',)
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/airflow/executors/celery_executor.py", line 52, in execute_command
    subprocess.check_call(command, shell=True)
  File "/usr/lib64/python3.6/subprocess.py", line 291, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command 'airflow run arl_source_emr_test_dag runEmrStep2WaiterTask 2018-08-07T00:00:00 --local -sd /var/lib/airflow/dags/arl_source_emr_test_dag.py' returned non-zero exit status 1.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.6/dist-packages/celery/app/trace.py", line 382, in trace_task
    R = retval = fun(*args, **kwargs)
  File "/usr/lib/python3.6/dist-packages/celery/app/trace.py", line 641, in __protected_call__
    return self.run(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/airflow/executors/celery_executor.py", line 55, in execute_command
    raise AirflowException('Celery command failed')
airflow.exceptions.AirflowException: Celery command failed

发生此错误时，任务在 Airflow 上被标记为失败，因此当任务中实际上没有出现任何问题时，我的 DAG 也会失败。

我使用 Redis 作为队列，使用 postgreSQL 作为元数据库。两者都是外部的 AWS 服务。我在我的公司环境中运行所有这些，这就是服务器的全名是ip-1.2.3.4.eco.tanonprod.comanyname.io. 看起来它想要在某个地方使用这个全名，但我不知道需要在哪里修复这个值，以便它得到ip-1.2.3.4.eco.tanonprod.comanyname.io而不只是ip-1.2.3.4.

这个问题真正奇怪的是它并不总是发生。当我运行 DAG 时，它似乎偶尔会随机发生。我的所有 DAG 上也会偶尔发生这种情况，因此它不仅仅是一个 DAG。我觉得很奇怪，但它是零星的，因为这意味着其他任务运行正在处理 IP 地址，无论这是什么都很好。

注意：出于隐私原因，我已将真实 IP 地址更改为 1.2.3.4。

回答：

https://github.com/apache/incubator-airflow/pull/2484

这正是我遇到的问题，AWS EC2 实例上的其他 Airflow 用户也遇到了这个问题。

Answer 1

我的 Mac 上也有类似的问题。它将其固定设置hostname_callable = socket:gethostname为airflow.cfg.

Answer 2

主机名在任务实例运行时设置，并设置为self.hostname = socket.getfqdn()，其中 socket 是 python 包import socket。

触发此错误的比较是：

fqdn = socket.getfqdn()
if fqdn != ti.hostname:
    logging.warning("The recorded hostname {ti.hostname} "
        "does not match this instance's hostname "
        "{fqdn}".format(**locals()))
    raise AirflowException("Hostname of job runner does not match")

当工作线程运行时，您的 ec2 实例上的主机名似乎正在发生变化。也许尝试按照此处所述手动设置主机名https://forums.aws.amazon.com/thread.jspa?threadID=246906并查看是否有效。