Helm in Practice

# install zip and unzip
apt update && apt install zip unzip jq -y

# Set the Terraform version
TERRAFORM_VERSION="1.10.3"
TERRAFORM_ZIP="terraform_${TERRAFORM_VERSION}_linux_amd64.zip"
TERRAFORM_URL="https://releases.hashicorp.com/terraform/${TERRAFORM_VERSION}/${TERRAFORM_ZIP}"

# Download and extract the Terraform binary
curl -LO $TERRAFORM_URL
unzip $TERRAFORM_ZIP
mv terraform /usr/local/bin/

# First of all, choose a directory where you want to store the files we will use.
PROJECT_NAME="learning-helm"

# Create the folder structure
mkdir -p $PROJECT_NAME

# Create a unique name for the SSH key to avoid conflicts
# with other keys in your ~/.ssh directory
# Make sure you are not overwriting an existing key
SSH_UNIQUE_NAME="$HOME/.ssh/$PROJECT_NAME"

# generate the keys (public and private)
# This will overwrite the keys if they already exist
ssh-keygen -t rsa \
    -b 4096 \
    -C "$PROJECT_NAME" \
    -f $SSH_UNIQUE_NAME -N "" \
    <<< y

# add the key to the ssh-agent
ssh-add $SSH_UNIQUE_NAME

# Export the DigitalOcean token.
# Get one here: https://cloud.digitalocean.com/account/api/tokens
export DIGITALOCEAN_TOKEN="[CHANGE_ME]"

# Choose the best region for you.
# More options here: https://www.digitalocean.com/docs/platform/availability-matrix/
export DIGITALOCEAN_REGION="fra1"

# I recommend using Ubuntu 25.10 for this project.
export DIGITALOCEAN_IMAGE="ubuntu-25-10-x64"

# SSH key variables
export DIGITALOCEAN_SSH_KEY_NAME="$SSH_UNIQUE_NAME"
export DIGITALOCEAN_SSH_PUBLIC_KEY_PATH="$SSH_UNIQUE_NAME.pub"
export DIGITALOCEAN_SSH_PRIVATE_KEY_PATH="$SSH_UNIQUE_NAME"

# VPC variables.
# You can use the default VPC or create a new one.
# Use doctl to get the VPC UUID (`doctl vpcs list`)
export DIGITALOCEAN_VPC_UUID="[CHANGE_ME]"
export DIGITALOCEAN_PROJECT_NAME="$PROJECT_NAME"

# Workspace cluster variables
export DIGITALOCEAN_WORKSPACE_VM_NAME="workspace"
# Change the size if needed but default is fine for most cases
export DIGITALOCEAN_WORKSPACE_VM_SIZE="s-2vcpu-4gb"

# Workload cluster variables
export DIGITALOCEAN_WORKLOAD_VMS_NAMES='["master", "worker"]'
# Change the size if needed but default is fine for most cases
export DIGITALOCEAN_WORKLOAD_VMS_SIZE="s-2vcpu-4gb"

# Create a Terraform variable file.
cat << EOF > $PROJECT_NAME/variables.tf
variable "region" {
  default = "${DIGITALOCEAN_REGION}"
}
variable "image" {
  default = "${DIGITALOCEAN_IMAGE}"
}
variable "vpc_uuid" {
  default = "${DIGITALOCEAN_VPC_UUID}"
}
variable "workspace_vm_size" {
  default = "${DIGITALOCEAN_WORKSPACE_VM_SIZE}"
}
variable "workspace_vm_name" {
  default = "${DIGITALOCEAN_WORKSPACE_VM_NAME}"
}
variable "workload_vms_size" {
  default = "${DIGITALOCEAN_WORKLOAD_VMS_SIZE}"
}
variable "workload_vms_names" {
  default = ${DIGITALOCEAN_WORKLOAD_VMS_NAMES}
}
variable "project_name" {
  default = "${DIGITALOCEAN_PROJECT_NAME}"
}
variable "ssh_key_name" {
  default = "${DIGITALOCEAN_SSH_KEY_NAME}"
}
variable "ssh_public_key_path" {
  default = "${DIGITALOCEAN_SSH_PUBLIC_KEY_PATH}"
}
variable "ssh_private_key_path" {
  default = "${DIGITALOCEAN_SSH_PRIVATE_KEY_PATH}"
}
EOF

cat << EOF > $PROJECT_NAME/main.tf
terraform {
  required_providers {
    digitalocean = {
      source = "digitalocean/digitalocean"
      version = "~> 2.0"
    }
  }
}

# Create a DigitalOcean project
resource "digitalocean_project" "learning_helm_project" {
  name        = var.project_name
  description = "Project for learning"
  purpose     = "Development"
  environment = "Development"
}

data "digitalocean_project" "project" {
  depends_on = [digitalocean_project.learning_helm_project]
  name       = var.project_name
}

# Resource: Define the SSH key to be used for all VMs
resource "digitalocean_ssh_key" "default_ssh_key" {
  name       = var.ssh_key_name
  public_key = file(var.ssh_public_key_path)
}

# Resource: Workload VMs
resource "digitalocean_droplet" "workload_vms" {
  for_each = { for name in var.workload_vms_names : name => name }

  image      = var.image
  name       = each.value
  region     = var.region
  size       = var.workload_vms_size
  ssh_keys   = [digitalocean_ssh_key.default_ssh_key.id]
  monitoring = false
  vpc_uuid   = var.vpc_uuid

  connection {
    agent       = false
    type        = "ssh"
    user        = "root"
    private_key = file(var.ssh_private_key_path)
    host        = self.ipv4_address
    timeout     = "5m"
  }
}

# Resource: Workspace VM
resource "digitalocean_droplet" "workspace_vm" {
  image      = var.image
  name       = var.workspace_vm_name
  region     = var.region