@Marvin If I'm creating a custom Docker image from scratch to run my Prefect flows in Kubernetes, what should its ENTRYPOINT be and what should the .yaml file look like for a deployment which uses my image?

When creating a custom Docker image from scratch to run your Prefect flows in a Kubernetes environment, there isn't a specific

ENTRYPOINT

that you need to set for the image because Prefect isn’t running as a long-lived process within the container. Instead, your Kubernetes Job or Pod definitions will specify the command that’s executed to run a flow when the container starts. However, you should ensure that your container has the Prefect library and dependencies necessary to execute your flow. The

.yaml

file for a Kubernetes deployment using your custom Docker image should define the Kubernetes objects required to schedule and run your Prefect flows. Below is an example snippet of what the

prefect.yaml

file might look like, as mentioned in the documentation:

yaml
# Generic metadata about this project
name: flows
prefect-version: 2.13.8

# The build section allows you to manage and build docker images
build:
  - prefect_docker.deployments.steps.build_docker_image:
      id: build-image
      requires: prefect-docker>=0.4.0
      image_name: "{{ $PREFECT_IMAGE_NAME }}"
      tag: latest
      dockerfile: ...

For a more detailed Kubernetes deployment

.yaml

file, you would need to define the specifics of your workload, such as the Pod, Job, or Deployment specifications, including things like environment variables (

PREFECT_API_URL

for example), the number of replicas, resource requests and limits, and so forth. Unfortunately, the provided document excerpts did not include a full example, but you might commonly see sections that define the deployment kind, metadata, labels, container image (your custom Docker image), commands, args, and various specs to handle your workload scheduling and execution. Please note that the

prefect.yaml

mentioned in the snippet is used by the

prefect deploy

command to deploy flows and manage Docker image building and pushing. For an actual Kubernetes deployment, you will have a different YAML file that contains the deployment configuration for Kubernetes. On a side note, for your deployment to communicate with the Prefect API, if you're using host networking on Linux, you can set the Prefect API URL via an environment variable like this:

bash
docker run --network="host" -e PREFECT_API_URL=<http://localhost:4200/api> your-custom-image

If you need the full

.yaml

example for deploying to Kubernetes or more specifics, I would recommend checking out the Prefect documentation or community examples that are more specific to your use case.