Hi there I m attempting to set up an ECS Agent as an ECS Far

Question

Hi there I m attempting to set up an ECS Agent as an ECS Fargate service but I need to scope the IAM permissions to the minimum requirements I was wondering if someone could explain why we need these permissions so that I can figure out how to scope them out ``` ec2 AuthorizeSecurityGroupIngress ec2 CreateSecurityGroup ec2 CreateTags ec2 DescribeNetworkInterfaces ec2 DescribeSecurityGroups ec2 DescribeSubnets ec2 DescribeVpcs ec2 DeleteSecurityGroup ```

Anna Geller · Answer

< Lana Dann> there would be a different IAM role you would need to set up for the ECS execution role and a different IAM role for task role This documentation includes both Additionally this blog post provides a walkthrough on how you can set this all up When it comes to explaining why specific permissions are needed Prefect agent needs to have permissions to register a task definition run an ECS task send logs to Cloudwatch and deregister task definition and to do all that some additional permissions are needed e g EC2 describe VPCs to lookup your VPC and subnet IDs required by ECS run task API Additionally if your flows use ECR for Docker images or S3 for storage and possibly results then you need S3 permissions too Both the docs and the blog post provide more information on that Additionally if you re really interested you could have a look at the to understand what exactly it is doing and why specific permissions are needed We have also recently updated the ECSRun run configuration docs it has many examples that hopefully explain the process and various possible configurations

Lana Dann · Answer

thanks quick followup q we d like to use datadog and not cloudwatch for our logging and we ve set up our container definitions to do so in that case can i remove all `logs ` permissions from the task policy also to clarify i don t have any issues using the provided execution role policy i just need to scope down the task role policy

Lana Dann · Answer

also i ve been following your blog post and wanted to say thank you for writing it

Lana Dann · Answer

also i understand the intuition behind needing to describe vpcs subnets etc but in what situation would the agent need to create or delete a security group

Anna Geller · Answer

Regarding sending ECS logs to datadog I think you could reach out to AWS and ask about it This should be possible because you can configure ECS log driver to be splunk so there must be an option to choose Datadog instead <https aws amazon com premiumsupport knowledge center ecs task fargate splunk log driver > Your execution IAM role may look different then based on how you configure your log driver e g you may need a permission to retrieve a secret to authenticate with this external logging service

Anna Geller · Answer

You re right you can remove the ec2 DeleteSecurityGroup as long as you don t need a Dask cluster that you would set up on ECS Some of those permissions there are not 100 stripped to the absolute vanilla case you re right about that For example you can have a look at the IAM role required by DaskCloudProvider it needs to delete a security group if it creates one as part of a Dask cluster deployment <https cloudprovider dask org en latest modules dask cloudprovider aws ecs html FargateCluster> You can use the task role provided as the agent role policy in the docs and remove one by one to see whether it affects your flows if you want absolutely 100 least privilege principle here

Lana Dann · Answer

thank you for your help i got the agent running i have a followup question on how we can use our ECS agent and the ECS flow run we have ECS tasks defined that have a command that kicks off a script that does the actual data work that we re trying to get done from my understanding we can use `ECSRun` and just pass in the ARN of the task definition and register our flow of one task and that one task is just running the ECS task but what if i want to define a dependency between two separate ECS tasks with separate task definitions when one finishes i d like to run the second also how can i create a flow that uses two different agents depending on the task

Anna Geller · Answer

< Lana Dann> you can set both the custom task definition as well as a custom label on the run configuration And you can modify a run configuration of a child flow from a parent flow Let me give you an example

Anna Geller · Answer

here is the example note that even though the parent flow runs in prod it runs a child flow on a dev agent due to labels Also the run config is different between parent and flow ```from prefect import Flow from prefect tasks prefect import create flow run wait for flow run from prefect storage import S3 from prefect run configs import ECSRun STORAGE = S3 bucket= your bucket name key= flows parent flow py stored as script=True local script path= parent flow py with Flow parent flow storage=STORAGE run config=ECSRun labels= prod task definition path= run task kwargs=dict cluster= prefectEcsCluster as flow child flow id = create flow run flow name= child flow name project name= child flow project run config=ECSRun labels= dev task role arn= arn aws iam XXXX role prefectTaskRole execution role arn= arn aws iam XXXX role prefectECSAgentTaskExecutionRole image= run task kwargs=dict cluster= prefectEcsCluster wait task = wait for flow run child flow id raise final state=True ```

Anna Geller · Answer

the last task ensures to wait until the child flow finishes after that you could trigger another task or child flow depending on your use case If you want more ECS examples check out this docstring <https docs prefect io api latest run configs html ecsrun>