Templates are JSON files that configure the various components of Packer in order to create one or more virtual machine images.

JSON files both human readable and computers readable. A template is a JSON object that has a set of keys configuring various components of Packer.

• builders (required): It is an array of one or more objects that defines the builders that will be used to create machine images for this template, and configures each of those builders.
• description (optional) : It is a string providing a description for the template.
• provisioners (optional) : It is an array of one or more objects that defines the provisioners that will be used to install and configure software for the machines created by each of the builders.
• post-processors (optional) : It is an array of one or more objects that defines the various post-processing steps to take with the built images.
• variables (optional): It is an object of one or more key/value strings that defines user variables contained in the template.

Example Template

{

  "variables": {
    "aws_access_key": "",
    "aws_secret_key": ""
  },

  "builders": [
   {
    "type": "amazon-ebs",
    "access_key": "{{user `aws_access_key`}}",
    "secret_key": "{{user `aws_secret_key`}}",
    "region": "us-east-1",
    "source_ami": "ami-02e680c4",
    "instance_type": "t2.micro",
    "ssh_username": "ubuntu",
    "ami_name": "packer {{timestamp}}"
   }
  ],

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

Continue with :

• Builders