ami.pkr.hcl

packer {
  required_version = ">= 1.8.0"
  required_plugins {
    amazon = {
      source  = "github.com/hashicorp/amazon"
      version = "~> 1"
    }
  }
}

locals {
  timestamp  = regex_replace(timestamp(), "[- TZ:]", "")
  ami_prefix = "nomad-${var.nomad_version}"
}

variable "aws_region" {
  type    = string
  default = "ap-south-1"
}

variable "dry_run" {
  type    = bool
  default = true
}

variable "nomad_version" {
  type    = string
  default = "1.6.1"
}

variable "install_docker" {
  type    = bool
  default = false
}

// Get the most recent Ubuntu AMI ID.
data "amazon-ami" "autogenerated_1" {
  filters = {
    architecture                       = "x86_64"
    "block-device-mapping.volume-type" = "gp2"
    name                               = "ubuntu/images/hvm-ssd/ubuntu-jammy-22.04-amd64-server-*"
    root-device-type                   = "ebs"
    virtualization-type                = "hvm"
  }

  most_recent = true
  owners      = ["099720109477"]
  region      = var.aws_region
}

source "amazon-ebs" "nomad" {
  skip_create_ami = var.dry_run

  # https://github.com/hashicorp/packer/issues/11656#issuecomment-1106564406
  temporary_key_pair_type = "ed25519"

  ami_description = "AMI for Nomad agents based on Ubuntu"
  ami_name        = var.install_docker ? "${local.ami_prefix}-docker-${local.timestamp}" : "${local.ami_prefix}-${local.timestamp}"

  instance_type         = "t2.micro"
  shutdown_behavior     = "terminate"
  force_deregister      = true
  force_delete_snapshot = true
  tags = {
    nomad_version   = var.nomad_version
    source_ami_id   = "{{ .SourceAMI }}"
    source_ami_name = "{{ .SourceAMIName }}"
    Name            = var.install_docker ? "${local.ami_prefix}-docker" : "${local.ami_prefix}"
  }

  region       = var.aws_region
  source_ami   = data.amazon-ami.autogenerated_1.id
  ssh_username = "ubuntu"
}

build {
  sources = ["source.amazon-ebs.nomad"]

  // wait for sometime for instance to properly initialise.
  provisioner "shell" {
    inline = ["sleep 15"]
  }

  provisioner "shell" {
    environment_vars = ["NOMAD_VERSION=${var.nomad_version}", "INSTALL_DOCKER=${var.install_docker}"]
    script           = "./setup.sh"
  }
}