@Marvin: How can I have a docker worker mount a local folder into the flow container? E.g. on the docker host I have /tmp/large-files and want to have it in the flow container as /mnt/large-files Please specifiy either using prefect worker start [...] (preferred solution) or using docker compose to start a prefect worker

To mount a local folder into a Prefect flow container using a Docker worker, you can either use the

prefect worker start

command or a Docker Compose configuration. Here's how you can achieve this: ### Using

prefect worker start

Command When starting a Prefect worker with the CLI, you can specify volume mounts using Docker options. However, the

prefect worker start

command doesn't directly support passing Docker-specific volume arguments. Instead, you might need to configure the Docker infrastructure directly in your deployment or use environment variables and Docker daemon configuration to achieve this. ### Using Docker Compose You can define the volume mount in a

docker-compose.yaml

file. Here's an example configuration:

yaml
version: '3'
services:
  worker:
    image: prefecthq/prefect:2-python3.12
    command: ["prefect", "worker", "start", "--pool", "docker-work", "--install-policy", "if-not-present"]
    volumes:
      - /tmp/large-files:/mnt/large-files
    environment:
      - DOCKER_HOST=unix:///var/run/docker.sock

In this configuration: - The

volumes

section specifies the host directory

/tmp/large-files

to be mounted to

/mnt/large-files

in the container. - The

command

section starts the worker using the

prefect worker start

command. For more details on Docker infrastructure in Prefect, you can refer to Prefect Docker Infrastructure Examples and Prefect Worker Documentation. If you have further questions or need more specific configurations, feel free to ask!

@Marvin: Ok, could I specifiy this in my prefect.yaml even?

Yes, you can specify Docker options like volume mounts in your

prefect.yaml

file, but it requires some indirect configuration. The

prefect.yaml

file is primarily used for deployment configurations, and you can define infrastructure settings that will be utilized during deployment. However, direct Docker volume mounts aren't specified directly in

prefect.yaml

without using a custom infrastructure block or referencing a Docker block. Here’s a general approach: 1. Infrastructure Block: Define a custom infrastructure block in your Prefect configuration that handles Docker specifics, including volume mounts. 2. Environment Variables: Use environment variables to dynamically set paths or other Docker options if needed. 3. Docker Block: You can create a custom Docker block in Prefect that specifies your image and volume mounts, and then reference this block in your

prefect.yaml

. For more detailed instructions, refer to the Prefect YAML documentation. If you need more specific guidance on setting up the infrastructure block or Docker block, feel free to ask!

@Marvin: I'm familiar with the yaml docs. Could you give me an example of how to solve it there?

To specify a Docker volume mount in your

prefect.yaml

file, you can define an infrastructure block that includes Docker-specific settings. Here is an example of how you might configure it:

yaml
version: 3

deployments:
  - name: my-flow-deployment
    flow_name: my-flow
    infrastructure:
      type: docker-container
      env:
        PREFECT_HOME: /mnt/large-files
      image: my-custom-image:latest
      volumes:
        - /tmp/large-files:/mnt/large-files

### Key Points: - Infrastructure Type: Set to

docker-container

to specify that the deployment will use Docker. - Environment Variables: You can set environment variables that the Docker container will use. - Image: Specify the Docker image to use. This could be a custom image that you have built. - Volumes: Define the volume mounts. Here,

/tmp/large-files

on the host is mounted to

/mnt/large-files

in the container. This configuration allows you to set up your Prefect deployment to use Docker infrastructure with specific volume mounts. For more details, you can refer to the Prefect YAML documentation. If you need further assistance or have specific requirements, feel free to ask!