(aws-ec2): VPC construct - make Internet Gateway creation fully controllable

[Obirah]

Describe the feature

Currently the Vpc construct contains logic that determines whether to create an internet gateway here.

There should be a feature that allows to control the creation of the internet gateway explicitly.

Use Case

I'm deploying VPCs in an enterprise environment that requires to create the VPC only with private subnets of the CDK type PRIVATE_WITH_EGRESS because our subnets are connected to a transit gateway and hence are not to be considered PRIVATE_ISOLATED - this is important for dynamic lookups, e.g. for EKS.

My Vpc looks like this:

new Vpc(this, "vpc", {
    availabilityZones: this.props.availabilityZones,
    enableDnsHostnames: true,
    enableDnsSupport: true,
    flowLogs: { traffic: this.flowLogOptions },
    ipAddresses: this.ipAddresses,
    natGateways: 0,
    subnetConfiguration: this.subnetConfiguration,
    vpcName: `${this.props.name}`,
    vpnGateway: false,
});

The subnet configuration like that:

{
    name: this.props.name,
    subnetType: SubnetType.PRIVATE_WITH_EGRESS,
    cidrMask: this.vpcCidrMask + azSubnetNetmask,
    reserved: false,
}

This setup results in an unwanted internet gateway being created. Of course, there's a simple workaround that I use:

vpc.node.tryRemoveChild('IGW');
vpc.node.tryRemoveChild('VPCGW');

Proposed Solution

There should be a createInternetGateway flag in the VpcProps that explicitly allows me to disable the creation of an internet gateway that precedes over the above mentioned computation in order to provide a clean convention-over-configuration approach.

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.85.0

Environment details (OS name and version, etc.)

any

[peterwoodworth]

Thanks for the FR, makes sense 👍🏻

[pahud]

related to aws/aws-cdk-rfcs#507 and #5927

[peterwoodworth]

Thanks, I was looking for that pahud

[github-actions]

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