Logging to S3 stops working when MLFlow import added to file

[k-lyda]

Apache Airflow version:
Apache Airflow [1.10.12]

Kubernetes version (if you are using kubernetes) (use kubectl version):
Client Version: version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.2", GitCommit:"52c56ce7a8272c798dbc29846288d7cd9fbae032", GitTreeState:"clean", BuildDate:"2020-04-16T11:56:40Z", GoVersion:"go1.13.9", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"13", GitVersion:"v1.13.12", GitCommit:"a8b52209ee172232b6db7a6e0ce2adc77458829f", GitTreeState:"clean", BuildDate:"2019-10-15T12:04:30Z", GoVersion:"go1.11.13", Compiler:"gc", Platform:"linux/amd64"}

Environment:

• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

What happened:
I want to save logs on S3 storage. I've added proper configuration. Logging is working fine, unless I add import of MLFlow library in any of the files.

I don't even have to use this tool, just
from mlflow.tracking import MlflowClient
is enough to break the logging to S3.

What you expected to happen:
There is probably some mismatch in s3 credentials, but I don't see any specific error message in logs.

How to reproduce it:

1. Setup logging to s3 with proper configuration entries or env vars

AIRFLOW__CORE__REMOTE_LOGGING: "True"
AIRFLOW__CORE__REMOTE_BASE_LOG_FOLDER: "s3://bucket/airflow/logs"
AIRFLOW__CORE__REMOTE_LOG_CONN_ID: "s3_connection_id"
AIRFLOW__CORE__ENCRYPT_S3_LOGS: "False"

2. Logging to s3 should work fine in sample dag.
3. Add from mlflow.tracking import MlflowClient to DAG file - logging to s3 is now not working.

Anything else we need to know:
This problem occurs every time, when MLFlow is imported to any file processed by Airflow.

[boring-cyborg[bot]]

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[bllach]

I have same issue with remote logging:
Apache Airflow version: 2.0.0

Environment:

• Cloud provider or hardware configuration: AWS S3
• OS (e.g. from /etc/os-release): Ubuntu 20.10 (Groovy Gorilla) [1PC] and Ubuntu 18.04.4 LTS (Bionic Beaver) [2PC]
• Kernel (e.g. uname -a): 5.8.0-36-generic (Ubuntu 20.10) [1PC] and 5.3.0-62-generic (Ubuntu 18.04) [2PC]
• Install tools: airflow-quick-start and airflow-config and airflow-Example Pipeline definition
• Others: Setup logging to s3, by env vars and airflow.cfg
  env:

  AIRFLOW__CORE__REMOTE_LOGGING: "True"
  AIRFLOW__CORE__REMOTE_BASE_LOG_FOLDER: "s3://bucket/airflow/logs"
  AIRFLOW__CORE__REMOTE_LOG_CONN_ID: "custom_s3_id"

  airflow.cfg

  [logging]
  remote_logging = True
  remote_log_conn_id = custom_s3_id
  remote_base_log_folder = s3://bucket/airflow/logs

• Python: 3.7.9 [1PC] and 3.6.9 [2PC]

What happened:
With Example Pipeline definition remote logging work fine, but after add import mlflow to dag code, airflow doesn't send logs to s3 storage.

What you expected to happen:
Remote logging works fine with import mlflow

How to reproduce it:

• Install airflow airflow-quick-start;
• Install mlflow mlflow-quick-start;
• Setup config with abowe env vars or airflow.cfg;
• Add s3 connection to airflow;
• Paste dag code airflow-Example Pipeline definition to dag dir;
• Add import mlflow to dag code;
• Run dag;

Anything else we need to know: Tested on 2 PC with different os and hardware

[ashb]

This sounds like mlflow is doing something to the python loggers on import that it shouldn't be doing, and is a bug in that library.

[potiuk]

There also might be another problem:

Do you also use/import snowflake provider as well? We have the ongoing problem with #12881 and that might be the root cause of the problem.

If that's the case, for now you might remove the provider (and snowflake-connector-python). We are working with snowflake team ( they just merged snowflakedb/snowflake-connector-python#591 and snowflakedb/snowflake-connector-python#592) and as soon as they release new version of the connector, this problem should be gone.

If you have it can you remove the snowflake import/library and let us know if it fixes the problem?

But if you do not import snowflake anywhere:

Solution to this 'snowflake' problem will also unblock upgrade to a newer version of requests and urrlib3 libraries which might be another reason why mlflow does not work.

But you should be able to manually upgrade requests library and urllib3 libraries to latest versions (even if they will tell that there is a 'requests/urllib3 conflict'. In the upcoming bugfix 1.10.15 release, this limitation will be gone, regardless if snowflake manages to release a new library or not, but for now you would have to upgrade those manually.

Could try it and let us know ?

[andriisoldatenko]

i can confirm it doesn't work if you add from mlflow.tracking import MlflowClient to any dag.
mlflow version: 1.19.0
airflow: 1.10.15

[jsnb-devoted]

Just ran into this issue as our team is starting to use MLFlow:
airflow: 2.1.3 (kubernetes executor)
mlflow: 1.20.0

All of our DAGs are able to send logs up to S3 but any DAGs that import MLFlow silently fail to upload the logs to s3. Tasks in the DAGs behave normally and can even sync other data to s3 just fine but the logging code does not appear to be running.

It feels like the MLFlow code is overriding the task log handler that we use to write the logs to s3. MLFlow init file does load a logging config (init file + logging config)
Could be related? I'll be filing an issue with MLFlow's project.

[jsnb-devoted]

I opened an issue with the mlflow project as it is likely an issue with their logging config. I did however find a work around which is to import mlflow inside of a function so that the import doesn't happen until the task's run time.

def train_model():
  import mlflow
  # ...
  pass

with DAG("my_dag",  schedule_interval='@daily') as dag:
  PythonOperator(
    task_id=f"training_model",
    python_callable=train_model,
  )

[adamwrobel-ext-gd]

@jsnb-devoted can you share a ticket number in mlflow project??