CDK for ECS - Subnet and Architecture type

Question

HI All

I have 2 questions on how to use CDK to deploy ECS using python.

1.  How do we set subnet on the cluster via CDK? The VPC is straightforward using the vpc parameter, however i could not find the param for subnet.
2. How do we set the architecture(x64 or ARM), using the CDK ?  While creating the task I need to set the architecture to a specific value as I am getting the following error: standard_init_linux.go:228: exec user process caused: exec format error

Thank you for your help.

Regards

MichaelFischer · Accepted Answer

You can specify specific subnets for your EC2 container instances and/or your AWSVPC network configuration (if you are using Fargate or AWSVPC networking for your tasks/services).

For EC2 instances, the options you can pass to `add_capacity` (for EC2) are [here](https://docs.aws.amazon.com/cdk/api/v2/python/aws_cdk.aws_ecs/AddCapacityOptions.html) - you want the `vpc_subnets` property.

For task networking, you can specify VPC subnets by specifying the `vpc_subnets` property to your [Ec2Service](https://docs.aws.amazon.com/cdk/api/v2/python/aws_cdk.aws_ecs/Ec2Service.html) or [FargateService](https://docs.aws.amazon.com/cdk/api/v2/python/aws_cdk.aws_ecs/FargateService.html) declarations.

If you want to run your task on Graviton2 (arm64 architecture), you don't need to declare the architecture of an ECS Task except on Fargate. At this writing, CDK does not yet have Level 2 construct support for architecture configurations in Task Definitions. You would have to use an [Escape Hatch](https://docs.aws.amazon.com/cdk/v2/guide/cfn_layer.html#cfn_layer_resource) to modify the underlying L1 construct ([CfnTaskDefinition](https://docs.aws.amazon.com/cdk/api/v2/python/aws_cdk.aws_ecs/CfnTaskDefinition.html) in particular) to set the `runtime_platform` property.

If you're running your task on an EC2 instance, you just need to make sure that the architecture of your EC2 instance matches the architecture of your container image - or, better still, create a multi-architecture container image.

tkansara · Answer

Hi Michael,

Thanks a bunch for your help. I was able to resolve this.

For everyone else:

```
runtime_platform_property = _ecs.CfnTaskDefinition.RuntimePlatformProperty(
            cpu_architecture="ARM64",
            operating_system_family="LINUX"
        )

cfn_task_defn = task_definition.node.default_child
cfn_task_defn.runtime_platform = runtime_platform_property

```
Thank you.

CDK for ECS - Subnet and Architecture type

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