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<@ULVA73B9P> I am using ECS Service, ECS Cluster, ...
# marvin-in-the-wild
i
@Marvin I am using ECS Service, ECS Cluster, ECS Task. I am running the worker in an ECS Service and I have 2 Docker images (1 running the Worker and 1 for Flow codes and flow dependencies). I want to use the standard Prefect Worker pool for my flow deployment. I want to use my Flow Docker image as the storage. Is this possible?
m
Oh joy, another day, another docker dilemma. Let me just ask: Are you using Prefect version 2.x or 3.x? I have to search accordingly, you know.
i
I am using 2.x
@Marvin I am using ECS Service, ECS Cluster, ECS Task. I am running the worker in an ECS Service and I have 2 Docker images (1 running the Worker and 1 for Flow codes and flow dependencies). I want to use the standard Prefect Worker pool for my flow deployment. I want to use my Flow Docker image as the storage. Is this possible? I'm using Prefect 2.18
m
Oh, the joys of Docker and ECS! Here’s what I managed to scrape from the Prefect 2.x documentation for your conundrum about using a flow Docker image as storage: 1. ECS Worker Service Set-Up: - You need to create an ECS task definition specifying the Docker image for the Prefect worker, the required resources, and the command it should run. (source: Prefect AWS ECS Guide) 2. Docker Image and Work Pool Configuration: - Prefect allows you to define custom Docker images for your deployments. You can specify Docker images to be built based on your code and dependencies. You might find it useful to set up a default Docker namespace using:
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prefect config set PREFECT_DEFAULT_DOCKER_BUILD_NAMESPACE=<docker-registry-url>/<organization-or-username>
When creating deployments, you can then use this namespace. (source: Prefect Deploy Guide) 3. Dependencies Within Docker: - If you're using custom Docker images, make sure to include all necessary dependencies. You can bake code and dependencies into images or specify additional packages to be installed at runtime. (source: Prefect Filesystems) Links here for your edification: - AWS ECS Guide - Prefect Deploy - Prefect Filesystems In short, yes, it looks like you can use your custom Docker image for the flow as storage; just ensure you properly configure the deployment and worker pool settings. Isn't cloud deployment fun?
i
@Marvin I created an ECS task definition specifying the Docker image for the Prefect worker. Can you show me how to deploy my prefect flow to use this docker image?
m
Alright, here’s a concise guide on deploying your Prefect flow with a custom Docker image. Could it get any more tedious? 1. Set up Your Deployment YAML: Create a YAML file for your deployment. This file will define the Docker image you wish to use, as well as additional configurations. 2. Example YAML Configuration: Here’s a basic structure for your deployment YAML:
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yaml
   version: 2

   flows:
     - name: my-flow
       description: My fantastic flow deployment using a custom Docker image
       work_pool: my-ecs-pool
       parameters: 
         example_param: "example_value"
       infra_overrides: 
         image: "my_registry/no-build-image:1.0"
         build: false
3. Deploying the Flow: Use the Prefect CLI to deploy the flow using this YAML:
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bash
   prefect deployment build ./my_flow.py:my_flow --name my-flow --pool my-ecs-pool --image my_registry/no-build-image:1.0 --build
   prefect deployment apply my-flow-deployment.yaml
4. Ensure Your Image is Available: The specified Docker image should be available in your deployment’s execution environment. Ensure it’s properly built and pushed to your Docker registry. 5. Run the Deployment: Finally, trigger a flow run:
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bash
   prefect deployment run my-flow/my-flow
6. References from Docs: For more detailed steps, feel free to dive into these exhilarating documents: - Prefect Deploy Guide - Deploying Flows Good luck, because as always, you’ll probably need it.
i
@Marvin prefect deployment build ./my_flow.py:my_flow --name my-flow --pool my-ecs-pool --image my_registry/no-build-image:1.0 --build prefect deployment apply my-flow-deployment.yaml Where should I execute this command? In the CICD or in the Flow Docker image build step?
m
Ah, the ever-present question of where to run those delightful commands. Here’s the rundown, so you can decide where to perform your ritual: 1. CICD Pipeline: - Running the commands in the CI/CD pipeline ensures that your deployment process is automated and consistent. This is ideal for environments where you want to automatically deploy new versions of your flow when changes are pushed to your repository. - Steps: - Add the 
prefect deployment build
command as part of your build process. - Apply the deployment using 
prefect deployment apply
after the Docker image is built and pushed. - Typical CI/CD Integration:
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yaml
     steps:
       - name: Build and Push Docker Image
         run: |
           docker build -t my_registry/no-build-image:1.0 .
           docker push my_registry/no-build-image:1.0
       - name: Build Prefect Deployment
         run: |
           prefect deployment build ./my_flow.py:my_flow --name my-flow --pool my-ecs-pool --image my_registry/no-build-image:1.0 --build
       - name: Apply Prefect Deployment
         run: |
           prefect deployment apply my-flow-deployment.yaml
2. Flow Docker Image Build Step: - This is less common unless you have a very specific reason to build and apply the Prefect deployment directly within the image build process. Generally, deployments should be managed at a higher level, outside of the individual Docker image build process. - However, if you’re feeling particularly adventurous or need to embed this within the Docker image for some mysterious reason, you can add the commands to your Dockerfile or as part of your entrypoint script. - Not Recommended, but if you must:
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Dockerfile
     FROM prefecthq/prefect:2.18
     RUN pip install -r requirements.txt
     COPY . /app
     WORKDIR /app
     RUN prefect deployment build ./my_flow.py:my_flow --name my-flow --pool my-ecs-pool --image my_registry/no-build-image:1.0 --build
     RUN prefect deployment apply my-flow-deployment.yaml
Verdict: Stick with the CI/CD pipeline. It keeps your deployment process clean, manageable, and aligned with best practices. Run the Prefect deployment commands there, right after building and pushing your Docker image.
i
@Marvin What is the --build in the command doing? prefect deployment build ./my_flow.py:my_flow --name my-flow --pool my-ecs-pool --image my_registry/no-build-image:1.0 --build
m
Ah, the elusive 
--build
parameter. It’s part of the thrilling saga of setting up your deployment correctly. When you use the 
--build
flag with the 
prefect deployment build
command, it tells Prefect to perform the build operations specified in your deployment configuration (
prefect.yaml
). What It Does: - Build Side Effects: The most common usage is to build Docker images as side effects for running your deployments. If you have specified any build instructions in your deployment configuration, the 
--build
flag ensures these instructions are executed. - Docker Integration: If you initialize your deployment with the Docker recipe, it will prompt you for the necessary details like image name and tag. This is where the 
--build
flag becomes critical as it ensures your Docker image is built according to these specifications. Usage:
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bash
prefect deployment build ./my_flow.py:my_flow --name my-flow --pool my-ecs-pool --image my_registry/no-build-image:1.0 --build
Documentation References: - Prefect Deploy Guide So, in plain terms, the 
--build
option ensures you're not just telling Prefect about your shiny new flow and Docker image; you're also making sure Prefect builds (or rebuilds) the associated Docker image or other relevant side effects. Now isn't that just thrilling?
i
@Marvin What if I dont want to build my docker image again during deployment. prefect deployment build ./my_flow.py:my_flow --name my-flow --pool my-ecs-pool --image my_registry/no-build-image:1.0 --build
m
Oh, what a relief it must be to avoid building that Docker image yet again. If you want to skip the unnecessary rebuilding process, just omit the 
--build
flag from your command. Here’s how you can modify your command:
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bash
prefect deployment build ./my_flow.py:my_flow --name my-flow --pool my-ecs-pool --image my_registry/no-build-image:1.0
This will simply reference the already existing Docker image 
my_registry/no-build-image:1.0
without attempting to rebuild it. Summary: - With 
--build
: Prefect attempts to build the Docker image specified. - Without 
--build
: Prefect assumes the Docker image is already built and available, and just sets up the deployment to use it. Keep things tidy and efficient, just how a paranoid android would prefer.
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