Shell Provisioner

Next we need to do things on the server (otherwise, what's the point?). To do so, we'll configure Provisioners.

The easiest it to run shell/bash scripts. Here's what that looks like using a Shell provisioner.

 1{
 2  "min_packer_version":"1.0.0",
 3  "variables":{ Click to show }
 4    "infra_name": "cloudcasts",
 5    "infra_env": "",
 6    "aws_region": "us-east-2",
 7    "aws_instance": "t3.small"
 8  }, 
 9  "builders":[
10    { Click to show }
11      "type":"amazon-ebs",
12      "ami_name":"{{user `infra_name`}}-{{user `infra_env`}}-{{timestamp}}-app",
13      "instance_type":"{{user `aws_instance`}}",
14      "region":"{{user `aws_region`}}",
15      "profile": "cloudcasts",
16 
17      "source_ami_filter": {
18        "filters": {
19          "architecture": "x86_64",
20          "name": "ubuntu/images/hvm-ssd/ubuntu-focal-20.04-amd64-server-*",
21          "root-device-type": "ebs",
22          "virtualization-type": "hvm"
23        },
24        "most_recent": true,
25        "owners": [
26          "099720109477"
27        ]
28      },
29      "ssh_username":"ubuntu",
30      "launch_block_device_mappings":[
31        {
32          "device_name":"/dev/sda1",
33          "volume_size":8,
34          "delete_on_termination":true,
35          "encrypted":false,
36          "volume_type":"gp3",
37          "throughput": 125,
38          "iops": 3000
39        }
40      ],
41      "tags":{
42        "Name":"{{user `infra_name`}}-{{user `infra_env`}}-{{timestamp}}-app",
43        "Project":"{{user `infra_name`}}",
44        "Environment":"{{user `infra_env`}}",
45        "Role":"baked-ami",
46        "Unique":"baked-ami-{{timestamp}}",
47        "ManagedBy":"packer",
48        "Component":"app"
49      }
50    } 
51  ],
52  "provisioners":[
53    {
54      "script": "{{template_dir}}/scripts/base.sh",
55      "type": "shell"
56    }
57  ]
58}

Here's the contents of scripts/base.sh:

 1#! /usr/bin/env bash
 2 
 3set -e
 4 
 5# Helps clear issues of not finding Ansible package,
 6# perhaps due to updates running when server is first spun up
 7sleep 10
 8 
 9export DEBIAN_FRONTEND="noninteractive"
10 
11# Install Ansible
12echo ">>>>>>>>>>> INSTALLING ANSIBLE"
13sudo apt-get update
14sudo apt-get install -y ansible

As you can see, it installs Ansible, which we'll use next.