Code for Deploy Kubernetes in an Existing AWS VPC with Kops and Terraform post

main-state.tf

resource "aws_s3_bucket" "state_store" {
  bucket        = "${var.name}-state"
  acl           = "private"
  force_destroy = true

  versioning {
    enabled = true
  }
  ...
}

main-vpc.tf

module "vpc" {
  source   = "./modules/vpc"
  name     = "${var.name}"
  env      = "${var.env}"
  vpc_cidr = "${var.vpc_cidr}"

  tags {
    Infra             = "${var.name}"
    Environment       = "${var.env}"
    Terraformed       = "true"
    KubernetesCluster = "${var.env}.${var.name}"
  }
}

module "subnet_pair" {
  source              = "./modules/subnet-pair"
  name                = "${var.name}"
  env                 = "${var.env}"
  vpc_id              = "${module.vpc.vpc_id}"
  vpc_cidr            = "${module.vpc.cidr_block}"
  internet_gateway_id = "${module.vpc.internet_gateway_id}"
  availability_zones  = "${var.azs}"

  tags {
    Infra             = "${var.name}"
    Environment       = "${var.env}"
    Terraformed       = "true"
    KubernetesCluster = "${var.env}.${var.name}"
  }
}

main-zone.tf

resource "aws_route53_zone" "public" {
  name          = "${var.name}"
  force_destroy = true
  ...
}

subnets-post.yml

subnets:
- egress: nat-0b2f7f77b15041515
  id: subnet-8db395d6
  name: us-east-1a
  type: Private
  zone: us-east-1a
- egress: nat-059d239e3f86f6da9
  id: subnet-fd6b41d0
  name: us-east-1c
  type: Private
  zone: us-east-1c
- egress: nat-0231eef9a93386f4a
  id: subnet-5fc6dd16
  name: us-east-1d
  type: Private
  zone: us-east-1d
- id: subnet-0ab39551
  name: utility-us-east-1a
  type: Utility
  zone: us-east-1a
- id: subnet-656b4148
  name: utility-us-east-1c
  type: Utility
  zone: us-east-1c
- id: subnet-cdc7dc84
  name: utility-us-east-1d
  type: Utility
  zone: us-east-1d

subnets-pre.yml

subnets:
- cidr: 10.20.32.0/19
  name: us-east-1a
  type: Private
  zone: us-east-1a
- cidr: 10.20.64.0/19
  name: us-east-1c
  type: Private
  zone: us-east-1c
- cidr: 10.20.96.0/19
  name: us-east-1d
  type: Private
  zone: us-east-1d
- cidr: 10.20.0.0/22
  name: utility-us-east-1a
  type: Utility
  zone: us-east-1a
- cidr: 10.20.4.0/22
  name: utility-us-east-1c
  type: Utility
  zone: us-east-1c
- cidr: 10.20.8.0/22
  name: utility-us-east-1d
  type: Utility
  zone: us-east-1d

I wrote a Terraform module you might be interesting in, it does much the same thing but much less steps:
https://github.com/FutureSharks/tf-kops-cluster
😃