AWS Iam Vpc

AWS IAM + VPC Foundation

What This Skill Produces

Generate Terraform for the AWS network foundation used by EKS:

• VPC
• public and private subnets across available AZs
• Internet gateway
• NAT gateway and route tables
• subnet route associations
• common tags and naming locals
• IAM inputs consumed by later EKS resources

Do not create the EKS cluster, node groups, ECR repositories, Kubernetes objects, Helm releases, or mirror jobs here.

Inputs

Required:

Defaults when the user does not provide values:

Generation Rules

• Read aws-tf-conventions before generating Terraform.
• Use explicit CIDRs in terraform.tfvars; do not pick hidden defaults inside modules.
• Tag subnets for Kubernetes load balancer discovery:
  • private: kubernetes.io/role/internal-elb = "1"
  • public: kubernetes.io/role/elb = "1"
  • both: kubernetes.io/cluster/<cluster-name> = "shared"
• Prefer private subnets for EKS node groups.
• Keep app ingress outside this skill; only provision AWS network foundation.

Preflight

Before generating apply instructions, include these checks:

aws sts get-caller-identity --query Account --output text
aws ec2 describe-availability-zones --region "$AWS_REGION" \
  --query 'AvailabilityZones[?State==`available`].ZoneName' --output text

Block if the active account does not equal AWS_ACCOUNT_ID.

Terraform Shape

The generated stack should expose network outputs for later skills:

output "vpc_id" {
  value = aws_vpc.this.id
}

output "private_subnet_ids" {
  value = [for subnet in aws_subnet.private : subnet.id]
}

output "public_subnet_ids" {
  value = [for subnet in aws_subnet.public : subnet.id]
}

Use locals for common tags:

locals {
  common_tags = {
    cluster    = var.cluster_name
    owner      = var.owner
    environment = var.environment
    managed-by = "terraform"
    workload   = "kas"
  }
}

Validation Checklist

• VPC CIDR and subnet CIDRs are explicit inputs.
• At least two AZs are used; three is preferred when available.
• Private subnets have outbound access through NAT.
• Kubernetes subnet discovery tags are present.
• Network outputs are available for eks-cluster and eks-nodes.
• No EKS, ECR, Helm, or Kubernetes objects are created here.