@Marvin When deploying a Prefect flow to a Prefect ECS work pool? How does prefect know which ECS task definition to use? Because in deployment script, it doesn't specify which task definition to use. I'm using Prefect 2.18

So, you want to know how Prefect magically knows which ECS task definition to use when the deployment script doesn't explicitly mention it? How predictable of you. Let's see what the Prefect 2.x documentation has to say about this. I'll search for relevant information in the Prefect 2.x docs now. According to the Prefect 2.x documentation, the connection between Prefect and ECS involves several components: - ECS Cluster and Service: This hosts the task definitions. The task definitions include both the worker task definition (which the Prefect worker uses) and the flow run task definition. - Prefect Worker: The worker, defined by the worker task definition, polls the work queue and kicks off ECS tasks based on those definitions. - ECS Task Execution: When the Prefect worker triggers a task, it uses the flow run task definition to execute the ECS task, which then pulls the flow code from the ECR (Elastic Container Registry). So, how does Prefect know which ECS task definition to use? It's configured in the ECS work pool setup within Prefect Cloud, which dictates the flow run task definition used to execute the tasks. You can delve deeper into the integration guide for more specifics: ECS and Prefect Integration Guide. Isn't that just depressingly straightforward?

Hi @Marvin , I'm looking at migrating to Prefect worker and I've been stuck trying to figure out how to pass AWS secret names to ECS task definitions via

flow.deploy

e.g. I tried passing it under

job_variables

job_variables = {
    "task_definition" : {
        "containerDefinitions": [
            {
                "secrets": secrets
            }
        ]
    }
}

hoping it'll be merged with the default ECS task definition but doesn't seem to work (I've tried a few variations). For reference, previously we would have pass in the list of AWS secret names to

ECSTask

as infrastructure to

Deployment.build_from_flow

which sets up the ECS task definition for the deployment. (I'm using Prefet 2.20.2)

Oh joy, another "ECS task secrets" conundrum. It's like the universe never runs out of complications. Anyway, you seem to be trying to pass AWS secret names to the ECS task definitions. Let’s dig into the Prefect 2.x docs for any signs of a life-saving solution to your plight. I’ll search specifically for how to pass secrets for ECS task definitions via

flow.deploy

. Give me a moment to look that up. It's almost like they designed it to make you ask this question. From my search through the docs, it seems that specifying secrets for ECS tasks when deploying a Prefect flow isn't as straightforward as one might wish. Your attempt to use

job_variables

to merge with the default ECS task definition doesn't appear to be the documented approach. According to the ECS and Prefect Integration Guide, some typical configurations include setting environment variables like

PREFECT_API_URL

and

PREFECT_API_KEY

, but nothing explicitly detailed regarding AWS secrets. Given the fragmentary clues, your best bet would be to define the ECS task definitions separately and reference them in your deployment configuration. Additionally, re-check that you’re using the correct structure for the

secrets

section within

containerDefinitions

. Here's an alternative way to ensure your ECS task definitions are correctly set up with secrets: 1. Manually define the ECS Task Definition with Secrets: Include the secrets in the

containerDefinitions

of your ECS task definition JSON and register it with ECS. 2. Reference the Task Definition in Your Deployment: Ensure your Prefect deployment script references this pre-configured task definition. If these steps don't work, you may be encountering a subtle bug or a misconfiguration. For further help, you might want to check the GitHub issues. Allow me to do that for you. I'll search the PrefectHQ GitHub repository for any relevant issues on this topic. It appears that this isn't as simple as adding a secret to the

job_variables

. There is an open issue describing the exact challenge you're facing: when passing a task definition to a Prefect AWS ECSTask, secrets defined in the ECS task definition are not passed to the container running the Prefect flow. The current state of affairs seems to be: 1. Prefect Worker Task Override: Prefect creates a container override when running tasks, which does not include secrets. 2. Manual Task Definition: You'll need to pre-define your ECS task definitions with secrets and reference them explicitly in your deployment. The GitHub discussion proposes a solution where task definition secrets and environment variables are used, but it hasn't been resolved yet. This explains why your attempts with

job_variables

have been fruitless. For now, try these steps: ### Workaround 1. Manually Register Task Definition: - Define your ECS task definition with the necessary secrets and register it manually in ECS. 2. Reference Task Definition in Flow Deployment: - In your deployment script, reference this specific ECS task definition ARN. Here’s a quick example on how you might deploy using a manually registered task definition:

python
from prefect.deployments import Deployment
from prefect_aws.ecs import ECSTask

task_def_arn = 'arn:aws:ecs:YOUR_TASK_DEFINITION_ARN'

ecs_task = ECSTask(
    task_definition_arn=task_def_arn,
)

deployment = Deployment.build_from_flow(
    flow=your_flow,
    name="your-deployment-name",
    infrastructure=ecs_task,
)

deployment.apply()

If you believe this issue is critical and you want to influence its priority, consider contributing to the discussion or the codebase. For more details, check these references: - Issue #13035 - ECS Task Definition Secrets