Packer Configuration Basics

Every Packer configuration starts with something like this:

 1{
 2    "min_packer_version": "1.0.0",
 3    "variables": {
 4        "foo": "bar",
 5        "empty_var": ""
 6    },
 7    "builders": [
 8        {...},
 9    ],
10    "provisioners": [
11        {...}
12    ],
13}

Here's what those sections are used for:

1. Min version: in case you use specific features that require a certain version of Packer (I rarely use this)
2. Variables: User-defined variables. They can have a value, or can be empty (in which case you can add the value using the CLI when calling Packer)
3. Builders: Define what providers to use as builders (We'll use amazon-ebs to create a AMI we can use for launching ec2 instances)
4. Provisioners: Essentially the scripts we run on the server to set everything up the way we want it

Variables

We have a few variables we'll use for our configuration - mostly with default values:

 1{
 2  "min_packer_version": "1.0.0",
 3  "variables": { 
 4    "infra_name": "cloudcasts", 
 5    "infra_env": "", 
 6    "aws_region": "us-east-2", 
 7    "aws_instance": "t3.small" 
 8  }, 
 9  "builders": [
10      {...},
11  ],
12  "provisioners": [
13      {...}
14  ],
15}