You’re on the right track—this is controlled in the ECS work pool’s Base Job Template under

job_configuration.task_definition.containerDefinitions

. In Prefect 3.x, you can add

privileged

and

linuxParameters.sharedMemorySize

to the container definition so every flow run launched by that pool inherits those settings. Important notes: - Privileged mode and shared memory sizing are only supported on ECS EC2 launch type. Fargate does not support

privileged

or

linuxParameters.sharedMemorySize

. If your pool uses Fargate, you’ll need to switch to EC2 (via capacity providers or

launchType: EC2

) for these to work. Example base job template edit (showing only the relevant sections). Add the highlighted fields under `containerDefinitions`:

{
  "job_configuration": {
    "task_definition": {
      "containerDefinitions": [
        {
          "image": "{{ image }}",
          "name": "{{ container_name }}",
          "privileged": true,
          "linuxParameters": {
            "sharedMemorySize": 4096
          }
        }
      ],
      "cpu": "{{ cpu }}",
      "family": "{{ family }}",
      "memory": "{{ memory }}",
      "executionRoleArn": "{{ execution_role_arn }}"
    },
    "task_run_request": {
      "launchType": "{{ launch_type }}",
      "cluster": "{{ cluster }}",
      "overrides": {
        "containerOverrides": [
          {
            "name": "{{ container_name }}",
            "command": "{{ command }}",
            "environment": "{{ env }}",
            "cpu": "{{ cpu }}",
            "memory": "{{ memory }}"
          }
        ],
        "cpu": "{{ cpu }}",
        "memory": "{{ memory }}",
        "taskRoleArn": "{{ task_role_arn }}"
      },
      "tags": "{{ labels }}",
      "taskDefinition": "{{ task_definition_arn }}",
      "capacityProviderStrategy": "{{ capacity_provider_strategy }}"
    },
    "container_name": "{{ container_name }}",
    "cluster": "{{ cluster }}"
  }
}

How to apply this: 1) Fetch the current default template to a file:

prefect work-pool get-default-base-job-template --type ecs > ecs-template.json

2) Edit

ecs-template.json

to add

privileged

and

linuxParameters.sharedMemorySize

as shown above. 3) Update your work pool:

prefect work-pool update "<your-pool-name>" --base-job-template ecs-template.json

Or do the same edit in the Prefect UI: Work Pools > your ECS pool > Base job template > JSON editor. A couple of gotchas: - If you set

task_run_request.launchType

to

FARGATE

or use a Fargate capacity provider, AWS will reject

privileged

and

sharedMemorySize

. Use EC2 capacity instead. - If you provide a

task_definition_arn

at deployment time, that ARN is used as-is and will override the template-synthesized task definition. In that case, put these settings into the task definition you reference. References - Prefect ECS guide: Prefect 3 ECS guide - Work pool CLI (for base job templates): prefect work-pool CLI docs - AWS ECS ContainerDefinition and linuxParameters: - ContainerDefinition API - LinuxParameters API - Fargate limitations (no privileged / shm sizing): Fargate task definition support Quick sanity check: Are you using ECS with EC2 capacity (not Fargate) on this work pool? If you’re on Fargate, I can suggest alternatives or help you switch to EC2 capacity providers.