How to create VPC that can be shared across stacks?

Question

I am trying to wrap my head around how to create a reusable VPC that can be used across multiple stacks using AWS CDK. I want to be able to create different stack per project an

Answer 1

I tried 0x32e0edfb answer and got some problem. so I fix like this.

VPC Stack

class VpcStack(core.Stack):

    def __init__(self, scope: core.Construct, id: str, **kwargs) -> None:
        super().__init__(scope, id, **kwargs)

        self.eks_vpc = ec2.Vpc(self, 'eks-vpc',
            cidr='10.1.0.0/16',
            max_azs=2
        )

share VPC to other Stack

class EksClusterStack(core.Stack):

    def __init__(self, scope: core.Construct, id: str, props: ec2.Vpc, **kwargs) -> None:
        super().__init__(scope, id, **kwargs)

        cluster = eks.Cluster(self, 'eks-control-plane',
            vpc=props,
            default_capacity=0
        )

and then app.py file

app = core.App()

vpc_stack = VpcStack(app, 'vpc-stack')
eks_cluster_stack = EksClusterStack(app, 'eks-cluster', vpc_stack.eks_vpc)

eks_cluster_stack.add_dependency(vpc_stack)

app.synth()

from_lookup is much better used on already existing VPC.

so I choose to use share-vpcs to share VPC information.

from_lookup only does the API call once - then, the data is cached in the cdk.context.json file, which should be committed to source control

That problem was when I recreating the same VPC.

cdk.context.json didn't update to lasted version. So when I use from_lookup always get old vpc-id.

I need to use cdk context --clear command and then deploy again. cdk.context.json would get lasted version vpc-id.

Finally, it can work properly on from_lookup method.

ref: https://github.com/aws/aws-cdk/blob/master/packages/%40aws-cdk/aws-eks/test/integ.eks-kubectl.lit.ts

https://docs.aws.amazon.com/cdk/latest/guide/context.html

Answer 2

If you intend to reuse the VPC in different stacks, I'd recommend placing it in a separate stack, since your VPC stack will have a different lifecycle than your application stacks.

Here's what I'd do. I hope you don't mind a bit of Python :)

First, define your VPC in VpcStack:

class VpcStack(core.Stack):
    def __init__(self, app: core.App, id: str, **kwargs) -> None:
        super().__init__(app, id, **kwargs)
        aws_ec2.Vpc(self, 'MyVPC', max_azs=3)

Then look it up in another stack:

class Stack1(core.Stack):
    def __init__(self, app: core.App, id: str, **kwargs) -> None:
        super().__init__(app, id, **kwargs)
        # Lookup the VPC named 'MyVPC' created in stack 'vpc-stack'
        my_vpc = aws_ec2.Vpc.from_lookup(self, 'MyVPC', vpc_name=f'vpc-stack/MyVPC')
        # You can now use the VPC in ECS cluster, etc.

And this would be your cdk_app.py:

app = core.App()
vpc = VpcStack(app, 'vpc-stack')
stack1 = Stack1(app, 'stack1')