packer/example.json

{
    "name": "my-custom-image",

    "builders": [
        {
            "type": "amazon-ebs",
            "region": "us-east-1",
            "source_ami": "ami-de0d9eb7"
        }
    ],

    "provisioners": [
        {
            "type": "shell",
            "path": "script.sh"
        }
    ],

    "outputs": [
        {
            "type": "vagrant"
        }
    ]
}