@Marvin what is the difference between DaskTaskRunner and DaskExecutor

The

DaskTaskRunner

is a type of task runner that provides an execution environment for tasks. When defining a flow, you can specify the

DaskTaskRunner

as the task runner, which allows the tasks called in that flow to be executed in parallel using Dask, a powerful distributed computing framework. The

DaskExecutor

, as mentioned in the Prefect release notes, refers to a component used in past versions of Prefect, known as Orion, which allowed tasks to run in parallel on simple local Dask clusters. It was designed to provide parallel task execution but did not fully expose the capabilities of Dask. With newer releases, feature parity with the existing

DaskExecutor

was achieved, allowing the creation of customizable temporary clusters and connection to existing Dask clusters. In summary, both the

DaskTaskRunner

and the

DaskExecutor

relate to harnessing the power of Dask for parallel execution within Prefect workflows. However,

DaskTaskRunner

currently appears to be the preferred method in Prefect 2.x for achieving parallel, distributed task execution. The main difference seems to be in the abstraction level and integration within the Prefect ecosystem.

@Marvin how can I execute flow in processes; in the past it was executor=LocalDaskExecutor(scheduler="processes")

To execute a flow in processes with Prefect 2.x, you'll use a similar concept you did with Prefect 1.x, but the specifics are significantly simplified. Prefect 2.x no longer requires the registration step that Prefect 1.x did, simplifying deployment. While the exact code snippet you would use in Prefect 2.x is not directly provided, you generally create a Deployment with specifications on how and where your flow will run. In the context of Dask, although not explicitly stated, you would similarly set up your infrastructure to use Dask to manage task execution. You would make a deployment specifying Dask as the infrastructure for execution. In Prefect 2.x, this could potentially replace the

LocalDaskExecutor(scheduler="processes")

, typically by configuring a

DaskTaskRunner

with settings that parallel the behavior of using processes. Unfortunately, a direct snippet or more detailed instructions weren't available in the exchanged documentation, but here's what I suggest based on my infinite knowledge: - Look for any updates to the official Prefect documentation that may have become available after my last update. - Check the API reference for

DaskTaskRunner

and related deployment configuration options in Prefect 2.x. - You might also want to seek out community discussions or reach out to Prefect support for more precise code examples if needed. Implementation details often change with new versions of software, but the principles remain relatively constant. If you want to achieve parallelism by using processes with Dask, you'll need to configure your Dask settings accordingly when setting up your Prefect flow deployment.