template.json

{
  "builders": [
    {
      "name"    : "CentOS7",
      "type"    : "amazon-ebs",
      "region"  : "us-east-1",
      "ami_name": "{{user `ami_name` | clean_ami_name}}",
      "tags"    : {
        "Name": "{{user `ami_name`}}"
      },
      "run_tags": {
        "Name": "{{user `ami_name`}}"
      },
      "run_volume_tags": {
        "Name": "{{user `ami_name`}}"
      },
      "snapshot_tags": {
        "Name": "{{user `ami_name`}}"
      },
      "source_ami_filter": {
        "filters": {
          "virtualization-type": "hvm",
          "name"               : "{{user `ami_regex`}}",
          "root-device-type"   : "ebs"
        },
        "owners": [
          "679593333241"
        ],
        "most_recent": true
      },
      "associate_public_ip_address"         : true,
      "communicator"                        : "ssh",
      "ssh_username"                        : "centos",
      "instance_type"                       : "t2.micro",
      "vpc_id"                              : "{{user `vpc_id`}}",
      "subnet_id"                           : "{{user `subnet_id`}}",
      "iam_instance_profile"                : "{{user `iam_prof`}}",
      "temporary_security_group_source_cidr": "{{user `temp_cidr`}}",
      "ami_users"                           : "{{user `ami_users`}}"
    }
  ],
  "provisioners": [
    {
      "type"            : "ansible",
      "playbook_file"   : "./ansible/playbook.yml",
      "user"            : "centos",
      "ansible_env_vars": [
        "ANSIBLE_REMOTE_TEMP='/tmp/.ansible/'",
        "ANSIBLE_REMOTE_USER=centos",
        "ANSIBLE_CONFIG='./ansible/ansible.cfg'"
      ]
    }
  ],
  "variables": {
    "temp_cidr" : "",
    "vpc_id"    : "{{env `VPC_ID`}}",
    "subnet_id" : "{{env `SUBNET_ID`}}",
    "iam_prof"  : "",
    "aws_region": "{{env `AWS_REGION`}}",
    "ami_regex" : "CentOS Linux 7 x86_64*",
    "ami_name"  : "CentOS-7-{{timestamp}}",
    "ami_users" : ""
  }
}