template.json

{
    "variables": {
        "region": "us-east-1"
    },
    "builders": [
      {
        "type": "amazon-ebs",
        "region": "{{user `region`}}",
        "source_ami_filter": {
          "filters": {
            "virtualization-type": "hvm",
            "name": "amzn2-ami-hvm-2.0.*.1-x86_64-ebs",
            "root-device-type": "ebs"
          },
          "owners": [
            "amazon"
          ],
          "most_recent": true
        },
        "instance_type": "t2.micro",
        "vpc_filter": {
            "filters": {
              "tag:Class": "packer"
            }
        },
        "subnet_filter": {
          "filters": {
            "tag:Network": "Public"
          },
          "most_free": true,
          "random": false
        },
        "ssh_username": "ec2-user",
        "ami_name": "gremlin-server-packer {{timestamp}}",
        "tags":{
          "Name": "GremlinServer - {{timestamp}}"
        }
      }
    ],
    "provisioners": [
      {
        "type": "shell",
        "inline": [
          "sudo amazon-linux-extras install ansible2"
        ]
      },
      {
        "type": "ansible-local",
        "playbook_file": "ansible/playbook.yml",
        "role_paths": [
          "ansible/gremlin-server"
        ]
      },
      {
        "type": "shell",
        "inline": [
          "rm .ssh/authorized_keys ; sudo rm /root/.ssh/authorized_keys"
        ]
      }
    ]
  }