aws-cdk: Cannot refer to subnet by name for imported VPC

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• I’m submitting a …

  • 🪲 bug report
  • 🚀 feature request
  • 📚 construct library gap
  • ☎️ security issue or vulnerability => Please see policy
  • ❓ support request => Please see note at the top of this template.

• What is the current behavior? If the current behavior is a 🪲bug🪲: Please provide the steps to reproduce Please describe/document how to deploy an L2 construct that has vpc_subnets argument of SubnetSelection type.

Documentation mentions: https://docs.aws.amazon.com/cdk/api/latest/python/aws_cdk.aws_ec2/SubnetSelection.html subnet_name, but it is unclear what it really is. Subnet (neither Cfn nor L2 construct ) does not have a subnet_name property.

I wasnt able to make it work, always getting jsii.errors.JSIIError: There are no subnets named 'xxxx' in this VPC. Use a different VPC subnet selection.

Example code piece:

vpc = aws_ec2.Vpc.from_lookup(
    scope=self,
    id='dev-eks-vpc',
    is_default=False,
    tags={
        'aws:cloudformation:stack-name':'dev-eks-vpc'
    }
)

eks_cluster = aws_eks.Cluster(
    scope=self,
    id='EksCluster',
    vpc=vpc,
    vpc_subnets=[aws_ec2.SubnetSelection(subnet_type=aws_ec2.SubnetType.PRIVATE)],
    cluster_name='EksCluster-dev',
    version='1.12'
)

eks_autoscaling_group = eks_cluster.add_capacity(
    id='EksClusterAsg',
    instance_type='m5.large',
    desired_capacity=2,
    vpc_subnets=aws_ec2.SubnetSelection(subnet_name='dev-eks-vpc/DevEksVpc/PrivateSubnet2')
)

for subnet_name I tried what’s under Name tag, logical id and physical id. None works

• What is the expected behavior (or behavior of feature suggested)? Document how to deploy resources in certain subnets.

• What is the motivation / use case for changing the behavior or adding this feature? It’s quite clear users want to have an abiility to control where are the resources deployed.

• Please tell us about your environment:

  • CDK CLI Version: 1.3.0
  • Module Version: 1.3.0
  • OS: [all]
  • Language: [all]

• Other information (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. associated pull-request, stackoverflow, gitter, etc) https://github.com/aws/aws-cdk/issues/2393 https://github.com/aws/aws-cdk/issues/1577