部署方式：docker+airflow+mysql+LocalExecutor
使用airflow的docker镜像
https://hub.docker.com/r/puckel/docker-airflow
使用默认的sqlite+SequentialExecutor启动：
$ docker run -d -p 8080:8080 puckel/docker-airflow webserver
将容器中的airflow.cfg拷贝出来修改
$ docker cp $container_id:/usr/local/airflow/airflow.cfg .
尝试使用自定义airflow.cfg
-v /usr/local/airflow/airflow.cfg:/usr/local/airflow/airflow.cfg
其中修改sql_alchemy_conn为mysql，修改executor = LocalExecutor
发现使用的还是SequentialExecutor
[2019-02-28 19:37:16,170] {{__init__.py:51}} INFO - Using executor SequentialExecutor
查看Dockerfile：docker-airflow/Dockerfile
ENTRYPOINT ["/entrypoint.sh"]
CMD ["webserver"] # set default arg for entrypoint
发现最后启动的脚本是entrypoint.sh
查看entrypoint.sh：docker-airflow/script/entrypoint.sh
: "${AIRFLOW__CORE__EXECUTOR:=${EXECUTOR:-Sequential}Executor}"
...
if [ "$AIRFLOW__CORE__EXECUTOR" != "SequentialExecutor" ]; then
AIRFLOW__CORE__SQL_ALCHEMY_CONN="postgresql+psycopg2://$POSTGRES_USER:$POSTGRES_PASSWORD@$POSTGRES_HOST:$POSTGRES_PORT/$POSTGRES_DB"
AIRFLOW__CELERY__RESULT_BACKEND="db+postgresql://$POSTGRES_USER:$POSTGRES_PASSWORD@$POSTGRES_HOST:$POSTGRES_PORT/$POSTGRES_DB"
wait_for_port "Postgres" "$POSTGRES_HOST" "$POSTGRES_PORT"
fi
...
case "$1" in
webserver)
airflow initdb
if [ "$AIRFLOW__CORE__EXECUTOR" = "LocalExecutor" ]; then
# With the "Local" executor it should all run in one container.
airflow scheduler &
fi
exec airflow webserver
;;
1）取环境变量EXECUTOR（取值为Sequential、Local等）来构造环境变量AIRFLOW__CORE__EXECUTOR；
2）如果AIRFLOW__CORE__EXECUTOR不是SequentialExecutor，就等待postgres（这里强制依赖postgres）；
3）如果启动参数为webserver，同时AIRFLOW__CORE__EXECUTOR=LocalExecutor，自动启动scheduler；
Due to Airflow’s automatic environment variable expansion, you can also set the env var AIRFLOW__CORE__* to temporarily overwrite airflow.cfg.
由于环境变量优先级高于airflow.cfg，所以即使修改了airflow.cfg中executor=LocalExecutor，实际使用的还是SequentialExecutor；将容器中的entrypoint.sh拷贝出来修改
$ docker cp $container_id:/entrypoint.sh .
注释掉以下行
#if [ "$AIRFLOW__CORE__EXECUTOR" != "SequentialExecutor" ]; then
# AIRFLOW__CORE__SQL_ALCHEMY_CONN="postgresql+psycopg2://$POSTGRES_USER:$POSTGRES_PASSWORD@$POSTGRES_HOST:$POSTGRES_PORT/$POSTGRES_DB"
# AIRFLOW__CELERY__RESULT_BACKEND="db+postgresql://$POSTGRES_USER:$POSTGRES_PASSWORD@$POSTGRES_HOST:$POSTGRES_PORT/$POSTGRES_DB"
# wait_for_port "Postgres" "$POSTGRES_HOST" "$POSTGRES_PORT"
#fi
启动命令
$ docker run -d -p 8080:8080 -e EXECUTOR=Local -v /usr/local/airflow/airflow.cfg:/usr/local/airflow/airflow.cfg -v /usr/local/airflow/entrypoint.sh:/entrypoint.sh -v /usr/local/airflow/dags:/usr/local/airflow/dags -v /usr/local/airflow/logs:/usr/local/airflow/logs puckel/docker-airflow webserver
虽然是单点，但是配合mesos+hdfs nfs可以做成高可用用于生产环境；
参考：
https://github.com/puckel/docker-airflow