Airflow live executor logs with DaskExecutor

1
votes

I have an Airflow installation (on Kubernetes). My setup uses DaskExecutor. I also configured remote logging to S3. However when the task is running I cannot see the log, and I get this error instead:

*** Log file does not exist: /airflow/logs/dbt/run_dbt/2018-11-01T06:00:00+00:00/3.log
*** Fetching from: http://airflow-worker-74d75ccd98-6g9h5:8793/log/dbt/run_dbt/2018-11-01T06:00:00+00:00/3.log
*** Failed to fetch log file from worker. HTTPConnectionPool(host='airflow-worker-74d75ccd98-6g9h5', port=8793): Max retries exceeded with url: /log/dbt/run_dbt/2018-11-01T06:00:00+00:00/3.log (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f7d0668ae80>: Failed to establish a new connection: [Errno -2] Name or service not known',))

Once the task is done, the log is shown correctly.

I believe what Airflow is doing is:

  • for finished tasks read logs from s3
  • for running tasks, connect to executor's log server endpoint and show that.

Looks like Airflow is using celery.worker_log_server_port to connect to my dask executor to fetch logs from there.

How to configure DaskExecutor to expose log server endpoint?

my configuration:

core    remote_logging          True 
core    remote_base_log_folder  s3://some-s3-path
core    executor                DaskExecutor    
dask    cluster_address         127.0.0.1:8786
celery  worker_log_server_port  8793

what i verified: - verified that the log file exists and is being written to on the executor while the task is running - called netstat -tunlp on executor container, but did not find any extra port exposed, where logs could be served from.

1
airflowdask

1 Answers

1
votes

UPDATE have a look at serve_logs airflow cli command - I believe it does exactly the same.

We solved the problem by simply starting a python HTTP handler on a worker.

Dockerfile:

RUN mkdir -p $AIRFLOW_HOME/serve
RUN ln -s $AIRFLOW_HOME/logs $AIRFLOW_HOME/serve/log

worker.sh (run by Docker CMD):

#!/usr/bin/env bash

cd $AIRFLOW_HOME/serve
python3 -m http.server 8793 &

cd -
dask-worker $@