Great question. Here’s a CI/CD blueprint we see most teams use when self-hosting Prefect Server on AWS ECS (assuming Prefect 3.x): High-level flow - Infrastructure as code: Provision Prefect Server on ECS/Fargate, RDS Postgres, load balancer, networking, and an ECS work pool/worker with Terraform/CloudFormation/CDK. - Build/push images: Build a Docker image for your flows and push to ECR; tag with the Git SHA. - Work pool + worker: Use an ECS work pool and run an ECS worker (as a small Fargate service) that submits flow runs to your ECS cluster. - Register/update deployments: From CI, publish deployments to the server using your repo as the source of truth and point at the ECR image. - Environments/promotion: Separate work pools for dev/stage/prod; promote by retargeting the work pool and/or image tag. - Upgrades: Blue/green or rolling deploy for the server service, with DB backups; keep client and server on compatible versions. What this looks like in practice 1) Provision infra (once) - ECS/Fargate service for Prefect Server (API/UI), fronted by an ALB - RDS Postgres for the Prefect database - An ECS cluster (can be the same one where flow runs land) - IAM roles/SSM/Secrets Manager for credentials and Prefect API key - An ECS work pool and a long-running ECS worker (small Fargate task) that has permissions to submit ECS tasks for your flow runs Docs: - Prefect ECS worker guide 2) Build and push flow image (CI step) - Build once per commit; push to ECR using the Git SHA tag - Keep images slim; pin Python/OS package versions for reproducibility Example GitHub Actions steps (conceptual):

- name: Build and push
  run: |
    docker build -t $ECR_URI:$GIT_SHA .
    aws ecr get-login-password --region $AWS_REGION | docker login --username AWS --password-stdin $ECR_URI
    docker push $ECR_URI:$GIT_SHA

3) Create/run an ECS work pool and worker (once) - Create a work pool in Prefect and start a worker that targets your ECS cluster; the worker needs AWS IAM permissions for ECS (and ECR if pulling private images). - Recommended to run the worker as its own tiny Fargate service so it auto-recovers and scales horizontally if needed. Docs: - ECS worker guide 4) Publish/update deployments from CI - Use your repo as the source and register deployments against your ECS work pool. - Point jobs to the ECR image you just built. In Prefect 3.x, use

flow.from_source(...).deploy(...)

(deployment build methods from 2.x were removed). Example Python-based deployment registration (works great in CI):

# deploy_register.py
import os
from prefect import flow

@flow
def etl():
    pass  # your flow

if __name__ == "__main__":
    git_sha = os.environ["GIT_SHA"]
    ecr_uri = os.environ["ECR_URI"]
    work_pool = os.environ.get("WORK_POOL", "ecs-prod")

    flow.from_source(
        source="<https://github.com/your-org/your-repo>",
        entrypoint="flows/etl.py:etl",
    ).deploy(
        name="etl-prod",
        work_pool_name=work_pool,
        version=git_sha,
        parameters={},
        job_variables={
            # ECS worker honors these; see ECS guide for available fields
            "image": f"{ecr_uri}:{git_sha}",
            # examples you might set:
            # "cpu": 1024,
            # "memory": 2048,
            # "task_role_arn": "...",
            # "execution_role_arn": "...",
            # "env": {"ENV": "prod"},
        },
    )

CI step to register:

- name: Register Prefect deployment
  env:
    PREFECT_API_URL: ${{ secrets.PREFECT_API_URL }}
    PREFECT_API_KEY: ${{ secrets.PREFECT_API_KEY }}
    GIT_SHA: ${{ github.sha }}
    ECR_URI: ${{ secrets.ECR_URI }}
    WORK_POOL: ecs-prod
  run: python deploy_register.py

Docs: - Store flow code and deploy from source 5) Secrets and config

- Keep Prefect API URL/API key in your CI secret store - Use AWS Secrets Manager or SSM for app secrets; inject as ECS task env vars in

job_variables

or via task definitions 6) Environment separation and promotion - Separate work pools per environment (e.g.,

ecs-dev

,

ecs-stg

,

ecs-prod

) and optionally separate VPCs/accounts - Promote by re-registering the deployment targeting another work pool and/or by retagging the image - Leverage deployment versioning to roll back if necessary - Blog: Deployment versioning and rollbacks 7) Prefect Server upgrades on ECS - Back up the database (RDS snapshot) - Blue/green or rolling update the ECS service with a newer Prefect Server image version - Keep your workers and deployment clients compatible with the server version (align major versions) - Validate migrations/compatibility in a staging environment before prod Helpful references - ECS worker guide - Store flow code / deploy from source - CI/CD guidance (blog) - Orchestrating with Docker (blog) - Serverless with Prefect + Pulumi on AWS (blog) Notes on CLI usage - Common commands you’ll use include

prefect work-pool create

,

prefect worker start

, and

prefect deploy

. I attempted to verify CLI help here but couldn’t run the checks in this environment. If you need exact flags, I’m happy to provide them and link the corresponding docs. Questions to tailor this for you - Which CI system are you using (GitHub Actions, GitLab CI, CircleCI, AWS CodeBuild)? - Are you planning to run the Prefect worker as a Fargate service or elsewhere? - Do you need multi-env promotion (dev/stage/prod) and/or multi-account AWS support? - Any special ECS constraints (custom task defs, VPC endpoints, private subnets only)?