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<@ULVA73B9P> Can a ECS worker create two different...
# ask-marvin
d
@Marvin Can a ECS worker create two different flow runs with different container images?
m
Yes, an ECS worker can create multiple flow runs with different container images. In Prefect, ECS tasks are defined by task definitions, which specify the Docker containers to run. Each flow run can have its own ECS task definition, allowing you to specify different container images for different flow runs. You can configure your ECS worker to handle multiple task definitions, each with its own container image, by setting up separate ECS services or using different task definitions as needed. The flexibility of ECS allows you to manage and execute Prefect flow runs using different configurations. For more details, you can explore the ECS Worker Guide.
d
@Marvin How do I overwrite the base job template image defined by the worker pool using the deployment?
m
To overwrite the base job template image defined by the worker pool using a deployment in Prefect, you can customize the deployment's job variables. Here's a concise guide on how to do it: 1. Define Job Variables: Each work pool has a base job template with job variables. These are infrastructure-related values that you can override on a per-deployment basis. 2. Override in Deployment: When creating a deployment, you can specify job variables to override the defaults set by the work pool. This includes specifying a different Docker image. 3. Using 
prefect.yaml
or Python: You can define these overrides in a 
prefect.yaml
file or programmatically using the Python deploy method. Here's a basic example in `prefect.yaml`:
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yaml
   deployments:
     - name: my-deployment
       work_pool_name: my-work-pool
       job_variables:
         image: my-custom-image:latest
4. Python Method: If you prefer using Python, you can achieve the same by setting the 
job_variables
parameter when deploying:
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python
   from prefect.deployments import Deployment

   deployment = Deployment.build_from_flow(
       flow=my_flow,
       name="my-deployment",
       work_pool_name="my-work-pool",
       job_variables={"image": "my-custom-image:latest"}
   )
   deployment.apply()
These steps allow you to dynamically change the container image used by the worker pool for a specific deployment. For more information, you can refer to the Prefect documentation on customizing deployments.
d
@Marvin Can you teach me how to do this using terraform?
m
To configure Prefect deployments using Terraform, you would typically use the Prefect Cloud Terraform provider. This allows you to manage your Prefect infrastructure as code. Here’s a general approach you can follow: 1. Terraform Provider: Use the Prefect Cloud Terraform provider to manage deployments and other resources. 2. Configuration: Define your Prefect deployments in Terraform configuration files. You can specify details such as the work pool, job variables, and image overrides. 3. Terraform Script: Here’s a basic example of what a Terraform script might look like. Note that this is a conceptual example, and you will need to adjust it according to your actual setup and Prefect Cloud account details:
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hcl
   provider "prefect" {
     api_key = "your-prefect-api-key"
   }

   resource "prefect_deployment" "my_deployment" {
     flow_id      = "your-flow-id"
     name         = "my-deployment"
     work_pool_id = "your-work-pool-id"
     
     job_variables = {
       image = "my-custom-image:latest"
     }
   }
4. Apply Configuration: Run 
terraform init
to initialize the configuration and 
terraform apply
to apply the changes, which will create or update the Prefect deployment with the specified settings. For specific details on the Terraform provider, you can check the Prefect Cloud Terraform provider documentation (look for the Terraform provider link). This setup will allow you to manage and deploy Prefect flows using Terraform, enabling infrastructure as code practices.
d
@Marvin I don't have an image input defined in the job_variable, this is my job code:
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"job_configuration": {
    "env": "{{ env }}",
    "name": "{{ name }}",
    "labels": "{{ labels }}",
    "vpc_id": "{{ vpc_id }}",
    "cluster": "{{ cluster }}",
    "command": "{{ command }}",
    "stream_output": "{{ stream_output }}",
    "container_name": "{{ container_name }}",
    "task_run_request": {
      "tags": "{{ labels }}",
      "cluster": "{{ cluster }}",
      "overrides": {
        "cpu": "{{ cpu }}",
        "memory": "{{ memory }}",
        "taskRoleArn": "{{ task_role_arn }}",
        "containerOverrides": [
          {
            "cpu": "{{ cpu }}",
            "name": "{{ container_name }}",
            "memory": "{{ memory }}",
            "command": "{{ command }}",
            "environment": "{{ env }}"
          }
        ]
      },
      "launchType": "{{ launch_type }}",
      "taskDefinition": "{{ task_definition_arn }}"
    },
m
To override the Docker image for your ECS tasks without a direct 
image
input in the job variables, you can modify the 
taskDefinition
in your Prefect deployment. Here's how you can approach this: 1. Task Definition: Ensure your ECS task definition is configured with the desired Docker image. The 
taskDefinition
ARN in your job configuration should point to this specific task definition. 2. Deployment Configuration: In your deployment, ensure the 
task_definition_arn
variable is set to the ARN of the task definition that uses the desired Docker image. 3. Terraform or Prefect YAML: If you are using Terraform or Prefect YAML, ensure that the deployment specifies this task definition ARN. Here's an example using Prefect YAML:
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yaml
   deployments:
     - name: my-deployment
       work_pool_name: my-work-pool
       job_variables:
         task_definition_arn: "arn:aws:ecs:region:account-id:task-definition/my-custom-task"
4. ECS Task Definition Update: If you need to change the image, update the ECS task definition in AWS to use the new image and update the ARN reference in your deployment configuration. By managing the task definition in AWS ECS, you can control which Docker image is used for your flow runs. Ensure your Prefect deployment is pointing to the correct task definition ARN for the desired image.
d
@Marvin can you add the image in the base job configuration?
m
To add the image directly in the base job configuration, you'll need to modify the 
containerOverrides
section within your 
job_configuration
. Here's how you can include the image: 1. Add Image to Container Overrides: Insert the 
image
key in the 
containerOverrides
section. This will allow you to specify the Docker image directly in the base job configuration. Here's how your modified job configuration might look:
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json
"job_configuration": {
  "env": "{{ env }}",
  "name": "{{ name }}",
  "labels": "{{ labels }}",
  "vpc_id": "{{ vpc_id }}",
  "cluster": "{{ cluster }}",
  "command": "{{ command }}",
  "stream_output": "{{ stream_output }}",
  "container_name": "{{ container_name }}",
  "task_run_request": {
    "tags": "{{ labels }}",
    "cluster": "{{ cluster }}",
    "overrides": {
      "cpu": "{{ cpu }}",
      "memory": "{{ memory }}",
      "taskRoleArn": "{{ task_role_arn }}",
      "containerOverrides": [
        {
          "cpu": "{{ cpu }}",
          "name": "{{ container_name }}",
          "memory": "{{ memory }}",
          "command": "{{ command }}",
          "environment": "{{ env }}",
          "image": "{{ image }}"
        }
      ]
    },
    "launchType": "{{ launch_type }}",
    "taskDefinition": "{{ task_definition_arn }}"
  }
}
2. Define the Image Variable: Make sure to define the 
image
variable in your deployment or work pool configuration so it can be interpolated in the job configuration. By doing this, you ensure that the image can be dynamically set per deployment or flow run, allowing for flexibility in specifying different Docker images as needed.
d
@Marvin Does it get ignored because I am already providing the taskdefinition arn?
m
Yes, if you are providing a 
taskDefinition
ARN in your ECS configuration, the 
image
specified in the 
containerOverrides
section will be ignored. The 
taskDefinition
ARN points to a pre-defined task definition in ECS, which includes all the container settings, including the image to be used. To change the image when using a task definition ARN, you have two main options: 1. Update the ECS Task Definition: Modify the ECS task definition directly in AWS to use the desired image. Then, update the ARN in your Prefect deployment to point to this updated task definition. 2. Create a New Task Definition: If you need to switch images frequently, consider creating a new task definition for each image change and update the ARN in your Prefect deployment accordingly. By managing the task definition, you ensure the correct image is used for your ECS tasks. The 
containerOverrides
are generally used to modify settings in the task definition, but they cannot override the image if the task definition is already specified.
✅ 1
d
@Marvin which variables are required when providing taskdefinition arn?
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"job_configuration": {
    "env": "{{ env }}",
    "name": "{{ name }}",
    "labels": "{{ labels }}",
    "vpc_id": "{{ vpc_id }}",
    "cluster": "{{ cluster }}",
    "command": "{{ command }}",
    "stream_output": "{{ stream_output }}",
    "container_name": "{{ container_name }}",
    "task_run_request": {
      "tags": "{{ labels }}",
      "cluster": "{{ cluster }}",
      "overrides": {
        "cpu": "{{ cpu }}",
        "memory": "{{ memory }}",
        "taskRoleArn": "{{ task_role_arn }}",
        "containerOverrides": [
          {
            "cpu": "{{ cpu }}",
            "name": "{{ container_name }}",
            "memory": "{{ memory }}",
            "command": "{{ command }}",
            "environment": "{{ env }}"
          }
        ]
      },
      "launchType": "{{ launch_type }}",
      "taskDefinition": "{{ task_definition_arn }}"
    },
    "network_configuration": "{{ network_configuration }}",
m
Your message was too long by 23 tokens...
When providing a Task Definition ARN for an ECS task in Prefect, the following variables are generally required: 1. Cluster: The name of the ECS cluster where the task will run. 2. Task Definition ARN: The Amazon Resource Name (ARN) for the task definition. 3. Container Name: The name of the container defined in the task. 4. Command: The command to run inside the container. 5. Environment Variables: Environment variables required by the container. 6. CPU and Memory: The CPU and memory allocations for the task. 7. Task Role ARN: The ARN of the IAM role that the task should assume. These variables are crucial for defining how the task should be executed within the ECS environment. For more details, you can refer to the Prefect AWS ECS Guide. If you have any specific requirements or configurations, you might want to ensure that the task definition matches those needs.
d
@Marvin, show me please example of base job template for ECS work pool type, where custom envvars, image and volumes are customized and tell me which ones are required and which ones are optional
m
Here's a basic example of a base job template for an ECS work pool type, focusing on customizing environment variables, the Docker image, and volumes:
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json
{
  "job_configuration": {
    "env": {
      "CUSTOM_ENV_VAR1": "value1",
      "CUSTOM_ENV_VAR2": "value2"
    },
    "image": "my-custom-image:latest",
    "volumes": [
      {
        "name": "my-volume",
        "host": {
          "sourcePath": "/path/on/host"
        }
      }
    ],
    "task_run_request": {
      "cluster": "my-ecs-cluster",
      "taskDefinition": "my-task-definition-arn",
      "overrides": {
        "containerOverrides": [
          {
            "name": "my-container-name",
            "environment": [
              {
                "name": "CUSTOM_ENV_VAR1",
                "value": "value1"
              },
              {
                "name": "CUSTOM_ENV_VAR2",
                "value": "value2"
              }
            ]
          }
        ]
      }
    }
  }
}
### Required Fields: - cluster: The ECS cluster where the task will run. - taskDefinition: The ARN of the task definition. - image: The Docker image to use for the container. - containerOverrides: This should include at least the container name. ### Optional Fields: - env: Custom environment variables. - volumes: Any volumes you want to attach to the container. For more detailed information, you can refer to the Prefect ECS Guide and the Work Pools Documentation.
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