Output private route table id

[StuartHarris]

When setting up a NAT instance, the private route table needs an extra route to direct outbound traffic to the NAT instance. By outputting the route table id, you can add the route later like this:

resource "aws_route" "outbound_internet" {
  route_table_id = "${module.vpc.private_route_table_id}"
  destination_cidr_block = "0.0.0.0/0"
  // TODO: but we've got 2 NAT instances - one in each AZ ...
  instance_id = "${element(split(",", module.nat.instance_ids), 0)}"
}

[antonbabenko]

Make sense, though I am personally not using this module, but rather combine networking from separate blocks (vpc - one module; private subnets with NAT - 2 modules (one module for subnet+route_table; second for running NAT instances); internet gateway - one module; public subnet - 1 module which is dependent on internet gateway module.

I also think that this change should be compatible with multiple route_tables, as there is already support for multiple private subnets in outputs - value = "${join(",", aws_route_table.private.*.id)}".

[willejs]

@StuartHarris Could you add the public route table too?

[zot24]

I think this PR can be closed now, isn't it? as per this have been implemented already https://github.com/terraform-community-modules/tf_aws_vpc/blob/master/outputs.tf#L18