Imported VPC errors when there are more than 1 public subnets in a route table

[MichaelHindley]

• I'm submitting a ...

  • [x] :beetle: bug report
  • [ ] :rocket: feature request
  • [ ] :books: construct library gap
  • [ ] :phone: security issue or vulnerability => Please see policy
  • [ ] :question: support request => Please see note at the top of this template.

• What is the current behavior? Have a RouteTable associated with 2 public subnets, try to add it to a imported vpc.

 publicSubnetIds: [cdk.Fn.importValue('PubSubId1'), cdk.Fn.importValue('PubSubId2')],
 publicSubnetRouteTableIds: ['RouteTableForBothPublicSubnetsId']

Results in Number of publicSubnetRouteTableIds (x) must be equal to the amount of publicSubnetIds (y)

• What is the expected behavior (or behavior of feature suggested)? The error message suggests that there MUST be a 1-to-1 mapping between the number of route tables and the number of public subnets, but this is not the case, screenie from the VPC that is imported that has this configuration:

• Please tell us about your environment:

  • CDK CLI Version: 1.2.0
  • Module Version: 1.2.0
  • OS: Win10
  • Language: TypeScript

[rix0rrr]

Not all VPC layouts are importable at the moment, only VPC layouts that mirror a VPC the CDK would create itself.

[rix0rrr]

Has been addressed

[mohammadaliqayyum]

@rix0rrr i do not understand why this issues is closed? I have one RouteTable and three PrivateSubnets and i am not able to import the RouteTable:

Error: Number of privateSubnetRouteTableIds (1) must be equal to the amount of privateSubnetIds (3).

@MichaelHindley have you solved this issue in someway?

[mohammadaliqayyum]

I needed this to be able to create a GatewayVpcEndpointAwsService for S3 and with the imported vpc with fromVpcAttributes i could not import the route tables. I have done the following work around:

// import VPC with other method by id
// create an SSM parameters which store the current VPC ID
new ssm.StringParameter(this, 'VPCID', {
    parameterName: `/VpcProvider/VPCID`,
    stringValue: String(vpcId)
});

// get vpc id so it can be used in vpc lookup
const vpcIdfromssm = ssm.StringParameter.valueFromLookup(this, '/VpcProvider/VPCID');

// use vpc id get from ssm to import vpc
const importVpc = ec2.Vpc.fromLookup(this, 'import-vpc', {
  vpcId: vpcIdfromssm,
});

// create S3 endpoint in imported vpc so that routetables can be edited
const s3Endpoint = importVpc.addGatewayEndpoint('s3Endpoint', {
  service: ec2.GatewayVpcEndpointAwsService.S3,
  subnets: [importVpc.selectSubnets({subnetType: ec2.SubnetType.PRIVATE})],
});

[gaspar09]

    /**
     * List of IDs of route tables for the public subnets.
     *
     * Must be undefined or have a name for every public subnet group.
     *
     * @default - Retrieving the route table ID of any public subnet will fail
     */
    readonly publicSubnetRouteTableIds?: string[];

I added the route table Id twice. Seemed to work.

 publicSubnetIds: [cdk.Fn.importValue('PubSubId1'), cdk.Fn.importValue('PubSubId2')],
 publicSubnetRouteTableIds: ['RouteTableForBothPublicSubnetsId', 'RouteTableForBothPublicSubnetsId']