@Marvin when i try and use a dask runner with prefect cloud it works, but when i set the PREFECT_API_URL to my self hosted prefect server, the worker and the client freezes. why could that be

Your issue with the Dask runner freezing when using a self-hosted Prefect server could be related to several factors. Here are some potential areas to investigate: 1. API Configuration: Ensure that the

PREFECT_API_URL

is correctly set to point to your self-hosted Prefect server. The correct setup is crucial for proper communication between your client and the server. You can refer to the self-hosted Prefect server documentation for more details. 2. Network and Firewall Settings: Verify that there are no network issues or firewall settings blocking communication between your Dask worker and the self-hosted Prefect server. 3. Dask and Prefect Versions: Ensure that both Prefect and Prefect-Dask are up-to-date. Compatibility issues between versions might cause unexpected behavior. You can find more about setting up Dask with Prefect here. 4. Server Logs: Check the logs of your self-hosted Prefect server for any errors or warnings that might indicate why the connection is not functioning as expected. If these suggestions don't resolve your issue, consider providing more specific error messages or logs to further diagnose the problem.

@Marvin what port does dask connect to the prefect server on

Dask does not connect to the Prefect server on a specific port. Instead, Dask connects to its own scheduler, which you must configure separately. When using the

DaskTaskRunner

in Prefect, you can specify the address of an existing Dask scheduler using the

address

parameter. Here's a brief explanation of how to set it up: - If you have an existing Dask cluster, provide the scheduler's address using the

address

argument when configuring the

DaskTaskRunner

. - The address typically looks like

<http://my-dask-cluster:8786>

, where

8786

is the default port for a Dask scheduler. For more details on setting up and using Dask with Prefect, you can refer to the Prefect Dask integration documentation.

@Marvin given that, why would dask pass or fail depending on whther i used prefect cloud or a slef hosted version

The difference in behavior when using Prefect Cloud versus a self-hosted Prefect server with Dask might be due to several factors: 1. Network Configuration: Prefect Cloud is a managed service with optimized network configurations. If your self-hosted server has network restrictions, firewall rules, or incorrect DNS settings, it might lead to connectivity issues with the Dask scheduler. 2. Environment Differences: The environment where the self-hosted server runs might have different configurations or resource limitations that affect the Dask cluster's performance or connectivity. 3. API and Authentication: Prefect Cloud might handle API requests and authentication differently compared to a self-hosted setup. Ensure that your self-hosted server is correctly configured to handle API requests and that any necessary authentication tokens or credentials are set up properly. 4. Version Mismatch: There might be a version mismatch between the Prefect and Prefect-Dask installations in your self-hosted environment compared to what Prefect Cloud uses. Ensure all components are up-to-date and compatible. 5. Logging and Error Messages: Check for any error messages or logs in both the Prefect server and Dask scheduler when running with the self-hosted version. They might provide clues about what is going wrong. If these suggestions don't resolve the issue, consider isolating the problem by testing Dask independently of Prefect, ensuring the Dask cluster can operate correctly on its own.