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

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')