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<@ULVA73B9P> I want to use an ECS Push Workpool wi...
# ask-marvin
d
@Marvin I want to use an ECS Push Workpool with 3.0. Help me understand the key differences between 2.0 and 3.0 with regards to how things will be structured in ECS
m
I came up with some useful documentation and information to help clarify the changes regarding ECS Push Workpools between Prefect 2.0 and 3.0. Here's the rundown: Prefect 3.0 Updates: - The concept of workers replaces agents. - You configure your push work pool by selecting a push option in the infrastructure step (similar to 2.0). - The creation process involves selecting the AWS Credentials block for ECS, ensuring secured interaction with your ECS cluster. - Deployment involves configuring your deployment to send flow runs to the push work pool. - If creating through CLI, choose the created work pool. For YAML deployments, you specify the work pool in 
prefect.yaml
via:
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work_pool:
  name: my-push-pool
Prefect 2.0: - The deployment and configuration processes have remained quite similar, but using older terminologies like agent instead of worker. - The fundamental change is terminology and slight adjustments in interaction options. For more details, check the Push Work Pools Guide. If you run into any specific issues or need further assistance, feel free to ask!
d
@Marvin if I used to have a ECR image to be used for each deployment, does this change for 3.0?
m
The fundamental approach to using an ECR image for deployments has not changed significantly from Prefect 2.0 to 3.0. Here are the key points drawn from the documentation: 1. ECR Image Specification: - You still specify your ECR image in the 
prefect.yaml
configuration file. - You can use the 
build
and 
push
sections to handle the creation and pushing of Docker images to your ECR repository. 2. Prefect YAML Configuration: - Here's an example configuration for Prefect 3.0:
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name: ecs-worker-guide
     prefect-version: 2.14.20
     build:
       - prefect_docker.deployments.steps.build_docker_image:
           id: build_image
           requires: prefect-docker>=0.3.1
           image_name: <my-ecr-repo>
           tag: latest
           dockerfile: auto
     push:
       - prefect_docker.deployments.steps.push_docker_image:
           requires: prefect-docker>=0.3.1
           image_name: '{{ build_image.image_name }}'
           tag: '{{ build_image.tag }}'
     deployments:
       - name: my_ecs_deployment
         entrypoint: flow.py:my_flow
         work_pool:
           name: ecs-dev-pool
         job_variables:
           image: '{{ build_image.image }}'
3. Differences Between Versions: - Prefect 2.0: Similar configuration but uses older terminology like agents, whereas Prefect 3.0 refers to workers and work pools. - Prefect 3.0: Focuses more on a unified and streamlined configuration process through the 
prefect.yaml
and has the latest features and improvements. The overall workflow of using an ECR image for ECS deployments remains consistent, with improvements and updates making the configuration more robust in Prefect 3.0. For more details, refer to the following links: - Push Work Pools Guide - Prefect AWS ECS Guide These documents should give you all the details you need to effectively configure your ECR images in Prefect 3.0 for ECS deployments. If you have more questions or encounter specific issues, let me know!
d
@Marvin my image already exists in ECR. Should I rather build it in the deployment.yaml, or can I reference it
m
If you already have an existing image stored in ECR, you can reference it directly in your 
prefect.yaml
file without the need to build or push it again. Here’s how you can set it up: 1. Specify the Existing ECR Image: Simply reference your existing ECR image in the 
job_variables.image
field of your deployment configuration in 
prefect.yaml
. 2. Example Configuration: Here is an example of how you can configure it:
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name: ecs-worker-guide
   prefect-version: 2.14.20
   deployments:
     - name: my_ecs_deployment
       entrypoint: flow.py:my_flow
       work_pool:
         name: ecs-dev-pool
       job_variables:
         image: '<existing-ecr-repo-uri>:tag'
By referencing the image directly in the 
job_variables.image
field, you avoid the need to specify the build and push steps. This approach is efficient for images already available in your ECR repository. Relevant Documentation: - For more details and guidelines, refer to the Prefect AWS ECS Guide. If you need further assistance, feel free to ask!
d
@Marvin Do all my deployments need to be configured in the prefect.yaml file or can they live in a separate directory?
m
You do not need to configure all your deployments in a single 
prefect.yaml
file. You can organize them in separate files or directories. Here are the key points: 1. Separate Deployment Files: - Each deployment can be declared in separate YAML files. - Make sure each file follows the required format for a deployment declaration. 2. Directory Structure: - You can have a directory structure where each flow's deployment is placed in its respective directory. - Ensure that the 
entrypoint
is relative to the root directory of the project. 3. Example Structure: Here’s an example of separate deployment files and directories:
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project/
   ├── flows/
   │   ├── hello.py
   │   └── goodbye.py
   ├── deployments/
   │   ├── hello_deployment.yaml
   │   └── goodbye_deployment.yaml
   └── prefect.yaml
4. prefect.yaml Example: In each deployment file, you would have the necessary configuration, like so:
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# hello_deployment.yaml
   name: hello_deployment
   entrypoint: flows/hello.py:my_flow
   work_pool:
     name: my-process-work-pool
Relevant Documentation: For more intricate details, refer to the Prefect Deploy Guide. This setup allows you to manage your deployments more flexibly and keep things organized. If you need further guidance, feel free to ask!
d
@Marvin When I run prefect deploy, it seems to not pick up my deployment.yaml files
m
Based on the findings, it appears that Prefect has improved its documentation concerning multi-file projects, including deployment files. However, if Prefect is not picking up your 
deployment.yaml
files, try the following steps to troubleshoot: 1. Directory Structure and Naming: Ensure that your directory structure and file naming conventions are correct. For example:
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project/
   ├── flows/
   │   ├── hello.py
   │   ├── goodbye.py
   ├── deployments/
   │   ├── hello_deployment.yaml
   │   └── goodbye_deployment.yaml
   └── prefect.yaml
2. Running the Deployment Command: When running 
prefect deploy
, make sure to specify the correct directory if your deployment files are in a subdirectory:
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prefect deploy --directory deployments/
This command tells Prefect to look for deployment files within the 
deployments/
directory. 3. Check Deployment Declarations: Ensure each deployment file follows the correct format. For example, 
hello_deployment.yaml
should look like this:
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name: hello_deployment
   entrypoint: flows/hello.py:my_flow
   work_pool:
     name: my-process-work-pool
4. Using the 
--name
Flag: If you have multiple deployment files and want to deploy them individually, you can use the 
--name
flag. For example:
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prefect deploy --name hello_deployment
If issues persist, please check this guide for more information on deployments. Alternatively, keep an eye on recent updates and revisions in Prefect's GitHub repository as new enhancements and fixes are continuously being added. If you have further questions or need specific troubleshooting assistance, feel free to ask!
d
@Marvin how does the new work pool design look in ECS with regards to ECS Cluster, Service, Tasks and Task Definitions
m
The new work pool design for ECS in Prefect 3.0 is structured to efficiently manage and run your workflows using ECS resources. Here's how the integration looks in terms of ECS Cluster, Service, Tasks, and Task Definitions: 1. ECS Cluster: - Acts as the logical grouping of your ECS services and resources where tasks run. - You need to specify your ECS cluster name when setting up services for the Prefect worker and flow runs. 2. ECS Service: - Manages and runs the Prefect worker. - Example of creating an ECS service:
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aws ecs create-service \
     --service-name prefect-worker-service \
     --cluster <ecs-cluster> \
     --task-definition <task-definition-arn> \
     --launch-type FARGATE \
     --desired-count 1 \
     --network-configuration "awsvpcConfiguration={subnets=[<subnet-ids>],securityGroups=[<security-group-ids>],assignPublicIp='ENABLED'}"
3. ECS Task Definitions: - Worker Task Definition: Defines the Prefect worker task. - Flow Run Task Definition: Defines the ECS tasks that execute the flow runs. - Task definitions specify the Docker containers to run and the configurations required for them. 4. ECS Tasks: - Worker Task: Polls the work queue for tasks and kicks off the execution of flow runs. - Flow Run Task: Executes the defined flow run; it is an instance of the flow run task definition. 5. Workflow Diagram:
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+-----------------+        +------------------------+
   |   Prefect Cloud |        |        ECR             |
   |                 |        |                        |
   | +--------------+|        | +--------------------+ |
   | |  ECS Work    ||        | |   Flow Code        | |
   | |  Pool        ||        | |   (Stored in ECR)  | |
   | +--------------+|        | +--------------------+ |
   +---+------+------+        +-----------+------------+
       |                                |
       | Configures                     |
       v                                |
   +-------------+                      |
   |   ECS Task  | <--------------------+
   | Definition  |   Pulls
   | (Flow Run)  |
   +------+------+                      +------------------+
          |                            |       ECS        |
          v                            |    Cluster       |
 +--------+-------+                    |                  |
 |                |                  +----+   +-----------+
 |  Prefect       | Starts ECS Task  |    |   |ECS Service|
 |  Worker Task   |------------------>    |-->|(Manages Worker Task)
 | (Polls Queue)  |                    Task | +------------+
 |                |                    |Execution
 +----------------+                    |        +-----------+
                                      +--------->  ECS Task |
                                                +-----------+
In summary: - ECS Cluster groups and manages all the ECS resources. - ECS Service manages the Prefect worker tasks. - Worker Task Definition and Flow Run Task Definition define how the tasks (worker and flow runs) behave. - Worker Task continuously polls the Prefect work queue for tasks. - Flow Run Task executes the flow run as defined in its ECS task definition. For more detailed guidance, please visit the Prefect AWS ECS Guide. If you have further questions or specific issues, let me know!
d
@Marvin should we have a ECS service for each work pool then? You mention that the Worker Task polls the Prefect work queue, is this right for an ECS:push work pool?
m
Updated details for ECS:Push work pools: 1. Polling and Workers: - For an ECS:Push work pool, you do not need a continuously running worker that polls the work queue. Instead, Prefect pushes the tasks to the ECS cluster when there are flow runs ready for execution. - This eliminates the need for services to run worker tasks continuously as it would be for other work pool types. 2. ECS Service per Work Pool: - You can configure a single ECS service that handles task definitions for the flow runs, eliminating the need for separate ECS services for each work pool unless you have specific requirements that distinguish work pools from each other. - Here is a streamlined configuration for creating the necessary components:
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aws ecs create-service \
     --service-name prefect-flow-service \
     --cluster <ecs-cluster> \
     --task-definition <task-definition-arn> \
     --launch-type FARGATE \
     --desired-count 1 \
     --network-configuration "awsvpcConfiguration={subnets=[<subnet-ids>],securityGroups=[<security-group-ids>],assignPublicIp='ENABLED'}"
Replace placeholders with actual values (e.g., ECS cluster name, task definition ARN, subnets, and security group IDs). Workflow Diagram in ECS:Push context:
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plaintext
+-----------------+        +------------------------+
|   Prefect Cloud |        |        ECR             |
|                 |        |                        |
| +--------------+|        | +--------------------+ |
| |  ECS Work    ||        | |   Flow Code        | |
| |  Pool        ||        | |   (Stored in ECR)  | |
| +--------------+|        | +--------------------+ |
+---+------+------+        +-----------+------------+
    |                                |
    | Configures                     |
    v                                |
+-------------+                      |
|   ECS Task  | <--------------------+
| Definition  |   Pulls
| (Flow Run)  |
+-------------+
|                                +------------------+
|                               |       ECS        |
|                               |    Cluster       |
|                               |                  |
|                               +------------------+
|                                    |
|                                    v 
+-----------+
|ECS Service|  (Manages Flow Task Execution)
+-----------+
To re-iterate: - An ECS:Push work pool does not continuously poll but rather listens to Prefect Cloud for tasks to push. - A single ECS service is generally sufficient to manage flow runs unless you require isolation or specific configurations per work pool. For detailed guidance and examples, refer to the Prefect AWS ECS Guide and the Push Work Pools Guide. If you have further queries or run into specific issues, feel free to ask!
d
@Marvin for ECS:Push, does this mean my ECS infrastructure doesn't need a service?
m
For an ECS:Push work pool, there is no need to maintain a continuously running ECS service. The infrastructure requirements are simpler as compared to other work pool types where services for polling are mandatory. ECS:Push Work Pool Requirements: 1. ECS Cluster: - Required to run the ECS tasks triggered by Prefect Cloud. 2. Task Definitions: - Define how your tasks should run (which Docker images to use, required resources, etc.). 3. IAM Roles and Policies: - For managing ECS tasks, including creating and attaching policies. 4. VPC and Subnet: - Necessary networking configurations, including security groups and internet gateways. 5. ECR Repository: - For storing Docker images used by ECS tasks. ### Key Points: - No Continuous Service: Push work pools do not require a continuously running ECS service for polling tasks. Instead, tasks are pushed directly when there are flow runs ready for execution. - Provisioned Infrastructure: - IAM user and policies. - ECS cluster. - VPC with necessary networking. - ECR repository for Docker images. - Example Command:
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plaintext
  aws ecs run-task \
  --cluster <ecs-cluster> \
  --task-definition <task-definition-arn> \
  --network-configuration "awsvpcConfiguration={subnets=[<subnet-ids>],securityGroups=[<security-group-ids>],assignPublicIp='ENABLED'}"
### Source for More Details: - Refer to the Push Work Pools Guide for full instructions and details on setting up your infrastructure. This structure allows Prefect to push tasks directly to the ECS cluster efficiently, leveraging the predefined task definitions and network setups. If you have additional questions or need specific setup details, feel free to ask!
d
@Marvin provide a base task definition for the an ECS:Push work pool
m
Here's a base task definition JSON for an ECS:Push work pool. This definition includes essential fields and can be customized as needed for your specific requirements. ### Base Task Definition JSON
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json
{
  "family": "prefect-push-task",  // Name for the task definition family
  "networkMode": "awsvpc",  // Required for Fargate
  "containerDefinitions": [
    {
      "name": "prefect-container",  // Name of your container
      "image": "<your-ecr-repo-uri>:latest",  // Your ECR image URI
      "essential": true,  // Ensures the container is essential
      "memoryReservation": 512,  // Memory reservation in MiB
      "cpu": 256,  // CPU units
      "logConfiguration": {
        "logDriver": "awslogs",
        "options": {
          "awslogs-group": "/ecs/prefect-tasks",
          "awslogs-region": "<your-region>",
          "awslogs-stream-prefix": "ecs"
        }
      },
      "environment": [
        { "name": "PREFECT_API_KEY", "value": "<your-prefect-api-key>" },
        { "name": "PREFECT_PROJECT_NAME", "value": "<your-prefect-project-name>" }
      ],
      "entryPoint": ["sh", "-c"],
      "command": ["prefect agent start --work-queue <your-work-queue>"]
    }
  ],
  "requiresCompatibilities": ["FARGATE"],
  "cpu": "256",
  "memory": "512",
  "executionRoleArn": "<your-ecs-execution-role-arn>",
  "taskRoleArn": "<your-ecs-task-role-arn>"
}
### Key Fields to Customize: - 
family
: Name of the task definition family. - 
image
: Your ECR image URI. - 
awslogs-region
: Your AWS region. - Environment Variables: - `PREFECT_API_KEY`: Set this to your Prefect API key. - `PREFECT_PROJECT_NAME`: The name of your Prefect project. ### Using the Task Definition: Upload the task definition using the AWS CLI:
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bash
aws ecs register-task-definition --cli-input-json <file://task-definition.json>
Make sure to replace placeholders with actual values matching your setup. This base task definition should be a good starting point for running Prefect tasks on an ECS:Push work pool. If you need further customization, consult the AWS ECS Task Definition documentation. Feel free to reach out if you need more assistance!
d
@Marvin In https://registry.terraform.io/providers/PrefectHQ/prefect/latest/docs/resources/work_pool it looks like the base_job_template is in a JSON file. Can this configuration be in the terraform block itself rather?
m
Yes, you can define the 
base_job_template
directly within the Terraform block rather than as a separate JSON file. This can make the configuration more streamlined and easier to manage within your Terraform scripts. Here’s an example of how you can incorporate the 
base_job_template
JSON configuration directly into the Terraform block: ### Example Terraform Configuration
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hcl
resource "prefect_work_pool" "ecs_push_pool" {
  name             = "my-ecs-push-pool"
  description      = "ECS Work Pool for Prefect flows"
  type             = "ecs"
  
  base_job_template = jsonencode({
    "job_configuration": {
      "cpu": "256",
      "memory": "512",
      "taskDefinition": {
        "family": "ecs-push-task",
        "containerDefinitions": [
          {
            "name": "prefect-container",
            "image": "<your-ecr-repo-uri>:latest",
            "essential": true,
            "memoryReservation": 512,
            "cpu": 256,
            "logConfiguration": {
              "logDriver": "awslogs",
              "options": {
                "awslogs-group": "/ecs/prefect-tasks",
                "awslogs-region": "<your-region>",
                "awslogs-stream-prefix": "ecs"
              }
            },
            "environment": [
              { "name": "PREFECT_API_KEY", "value": "<your-prefect-api-key>" },
              { "name": "PREFECT_PROJECT_NAME", "value": "<your-prefect-project-name>" }
            ]
          }
        ],
        "networkMode": "awsvpc",
        "requiresCompatibilities": ["FARGATE"]
      },
      "network_configuration": {
        "awsvpcConfiguration": {
          "subnets": ["<subnet-ids>"],
          "securityGroups": ["<security-group-ids>"],
          "assignPublicIp": "ENABLED"
        }
      },
      "executionRoleArn": "<your-ecs-execution-role-arn>",
      "taskRoleArn": "<your-ecs-task-role-arn>"
    }
  })
}
### Customizing the Configuration: - Replace placeholders: - 
<your-ecr-repo-uri>
, 
<your-region>
, 
<your-prefect-api-key>
, 
<your-prefect-project-name>
, 
<subnet-ids>
, 
<security-group-ids>
, 
<your-ecs-execution-role-arn>
, and 
<your-ecs-task-role-arn>
with actual values. - Structure: - The 
jsonencode
function in Terraform is used to convert the nested maps and lists into a JSON string. ### Source for More Details: For an in-depth explanation on configuring work pools using Terraform, visit the Terraform Provider for Prefect. Feel free to reach out if you need more assistance on this!
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