Unused route table created when creating a subnet

[Kent1]

• 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?
  When i create a Subnet, and change the RouteTableAssociation to an existing route table, an unused route table is created along with the subnet.

• What is the expected behavior (or behavior of feature suggested)?
  I would like to be able to remove this route table or that cdk is smart enough to not create it

• Please tell us about your environment:

  • CDK CLI Version: 1.3.0
  • Module Version: 1.3.0
  • OS: [OSX Mojave]
  • Language: [Java]

• 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)

Subnet Subnet = new Subnet(this, "Subnet", SubnetProps.builder()
        .withVpcId(vpc.getVpcId())
        .withAvailabilityZone("eu-west-1b")
        .withCidrBlock(String.format("10.%d.43.128/25", environmentId))
        .build());

CfnSubnetRouteTableAssociation routeTableAssociation = (CfnSubnetRouteTableAssociation) subnet.getNode().tryFindChild("RouteTableAssociation");
routeTableAssociation.setRouteTableId(Fn.importValue(String.format("%s-nat-nat000", environment)));

CfnRouteTable cfnRouteTable = (CfnRouteTable) subnet.getNode().tryFindChild("RouteTable");

[rix0rrr]

I'm not sure this counts as a bug.

Unfortunately, the Subnet construct right now is heavily tied to the Vpc construct, and supports exactly the features it needs.

This sounds like a feature request for an optional RouteTable input parameter to Subnet.

[konstantinj]

#4308 RouteTable input would be appreciated.
Not only in SubnetProps but also in subnetConfiguration so it can be used directly in the VPC construct.

[rix0rrr]

Related to #5927

[Obirah]

In TypeScript I was able to get rid of the RouteTable via subnet.node.tryRemoveChild('RouteTable');.

[github-actions]

This issue has not received any attention in 1 year. If you want to keep this issue open, please leave a comment below and auto-close will be canceled.

[japerwu]

I wish this feature is there. subnet.node.tryRemoveChild('RouteTable') results in unresolved dependency in my CFN template as the subnet still tries to reference it.

[maggoun]

I want this feature, the ability to assign a route table to a created subnet

[Vulonus]

i second this. i need a functionality like this. can we reopen the issue?

[Vulonus]

nvm this could be fixed when implementing #4308