✅ thought for 411.4 seconds

Short answer: yes. In Prefect 3.x, an ECS worker is just a process that calls the ECS API. If a deployment in the same ECS work pool sets

cluster

(and other ECS job variables) to a different ECS cluster, the worker will submit the task to that target cluster. The worker’s own ECS cluster does not constrain where it launches tasks. Key requirements/considerations: - Permissions: The worker’s AWS credentials must allow ecs:RunTask, ecs:DescribeTasks, iam:PassRole (for your task role), logs permissions, etc., on the target cluster’s account/region. - Region: If the target cluster is in a different region, make sure the worker’s AWS client is configured for that region (e.g., via

AWS_REGION/AWS_DEFAULT_REGION

on the worker) or use a per-deployment region setting if you maintain one. Many teams run one worker per region to keep this simple. - Networking: Ensure the subnets/security groups you provide are valid for the target cluster’s VPC. Example deployment job_variables (typical fields):

job_variables:
  cluster: "arn:aws:ecs:us-east-1:123456789012:cluster/other-cluster"
  launch_type: "FARGATE"
  cpu: 1024
  memory: 2048
  image: "<http://123456789012.dkr.ecr.us-east-1.amazonaws.com/prefect:latest|123456789012.dkr.ecr.us-east-1.amazonaws.com/prefect:latest>"
  task_role_arn: "arn:aws:iam::123456789012:role/my-task-role"
  execution_role_arn: "arn:aws:iam::123456789012:role/my-execution-role"
  subnets: ["subnet-abc", "subnet-def"]
  security_groups: ["sg-0123456789abcdef0"]
  assign_public_ip: true
  environment:
    PREFECT_API_URL: "<https://api.prefect.cloud/api/accounts/.../workspaces/...>"

Docs for reference: - ECS worker guide: Prefect 3 ECS guide - Overriding deployment job variables: Customize job variables Quick check: Are your two ECS clusters in the same AWS region/account? If they’re cross-region or cross-account, I can suggest the cleanest config for region and IAM.

Short answer: yes. Assuming Prefect 3.x, an ECS worker will launch the flow run in the ECS cluster specified by the deployment’s job variables. The worker’s own runtime location (e.g., running as a service in Cluster A) does not restrict where it submits tasks; it will call ECS to run the task in Cluster B if that’s what the deployment config says. Key points: - Precedence: deployment

job_variables

override the work pool’s base job template. The worker uses the merged result to submit the ECS task. - One worker can target many clusters: as long as it has the right AWS credentials/permissions, it can launch tasks in any cluster you specify per deployment. - IAM and region gotchas: - Ensure the worker’s AWS identity can call

ecs:RunTask

,

ecs:DescribeClusters

,

ecs:RegisterTaskDefinition

,

iam:PassRole

(for task/execution roles), CloudWatch Logs permissions, and required EC2 networking permissions in the target cluster’s account/region. - If you’re targeting multiple regions or accounts, pass credentials/region per deployment (e.g., via an AwsCredentials block in

job_variables

) or run a worker per region. - Make sure networking settings (subnets, security groups, assign_public_ip, capacity provider/launch type) match the target cluster’s VPC. Example deployment snippet (Prefect 3.x) showing cluster override:

deployments:
  - name: my-flow-on-cluster-b
    entrypoint: flows/my_flow.py:flow
    work_pool:
      name: my-ecs-pool
      job_variables:
        # per-deployment overrides
        cluster: arn:aws:ecs:us-east-1:123456789012:cluster/cluster-b
        subnets: ["subnet-abc", "subnet-def"]
        security_groups: ["sg-12345"]
        launch_type: FARGATE
        cpu: 1024
        memory: 2048
        image: <http://123456789012.dkr.ecr.us-east-1.amazonaws.com/my-image:latest|123456789012.dkr.ecr.us-east-1.amazonaws.com/my-image:latest>
        # optionally target another account/region
        # aws_credentials: { block: "my-prod-aws-creds" }

Docs for deeper details: - ECS worker guide: Prefect ECS guide - Work pools and precedence: Work pools - Overriding job variables per deployment: Customize job variables If you share which regions/accounts your clusters live in, I can suggest the cleanest way to handle credentials/region (per-deployment vs per-worker).