This is the Base AMI for Medium Article based on usage of Packer on AWS

base_ami.json

{
  "variables": {
  "aws_access_key": "${AWS_ACCESS_KEY_ID}",
  "aws_secret_key": "${AWS_SECRET_ACCESS_KEY}",
  "vpc_region": "${vpc_region}",
  "vpc_id": "${vpc_id}",
  "vpc_public_sn_id": "${vpc_public_sn_id}",
  "vpc_public_sg_id": "${vpc_public_sg_id}",
  "source_ami": "${source_ami}",
  "instance_type": "${instance_type}",
  "ssh_username": "${ssh_username}"
},
  "builders": [
    {
      "type": "amazon-ebs",
      "access_key": "{{user `aws_access_key`}}",
      "secret_key": "{{user `aws_secret_key`}}",
      "region": "{{user `vpc_region`}}",
      "vpc_id": "{{user `vpc_id`}}",
      "subnet_id": "{{user `vpc_public_sn_id`}}",
      "associate_public_ip_address": true,
      "security_group_id": "{{user `vpc_public_sg_id`}}",
      "source_ami": "{{user `source_ami`}}",
      "instance_type": "{{user `instance_type`}}",
      "ssh_username": "{{user `ssh_username`}}",
      "ami_name": "base-ami-{{isotime \"2006-01-02-1504\"}}",
      "ami_groups": "all",
      "launch_block_device_mappings": [
        {
          "device_name": "/dev/sda1",
          "volume_type": "gp2",
          "volume_size": "30",
          "delete_on_termination": true
        }
      ]
    }
  ],
  "provisioners": [
    {
      "type": "shell",
      "script": "baseInit.sh"
    }
  ],
  "post-processors": [
    {
      "type": "manifest",
      "output": "manifest.json",
      "strip_path": true
    }
  ]
}