{
  "variables": {
    "access_key": "{{env `AWS_ACCESS_KEY_ID`}}",
    "secret_key": "{{env `AWS_SECRET_ACCESS_KEY`}}"
  },
  "builders": [{
    "type": "amazon-ebs",
    "access_key": "{{user `access_key`}}",
    "secret_key": "{{user `secret_key`}}",
    "region": "us-east-1",
    "source_ami": "ami-fce3c696,",
    "instance_type": "t2.micro",
    "ssh_username": "ubuntu",
    "ami_name": "packer-example {{timestamp}}"
  }]
}]

  "provisioners": [{
    "type": "shell",
    "inline": [
      "sleep 15",
      "sudo yum update -y"
    ]
  }]
}