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Terraform Hetzner Cloud Setup ​

Quick reference for the Hetzner Cloud Terraform setup used across the exercises.

Prerequisites ​

  • Terraform >= 1.0
  • Hetzner Cloud account and API token

Project Structure ​

text
terraform/
├── main.tf           # Provider configuration
├── variables.tf      # Input variables
├── resources.tf      # Infrastructure resources
├── outputs.tf        # Output values
├── terraform.tfvars  # Non-sensitive configuration
├── .env.example      # Environment template
└── .env              # Sensitive values (ignored by Git)

Configuration Overview ​

The setup creates a cost-optimized Hetzner Cloud server with the following components:

  • Server: cx22 instance in Nuremberg running Debian 12
  • SSH Keys: Primary and optional secondary key deployment
  • Firewall: SSH access with outbound traffic allowed
  • Network: Public IPv4 and IPv6 addresses
  • Auto-naming: Incremental server names (server-1, server-2, etc.)

Initial Setup ​

Environment Configuration ​

  1. Navigate to the terraform directory:
bash
cd terraform
  1. Create environment file from template:
bash
cp .env.example .env
  1. Edit .env with your credentials:
bash
export HCLOUD_TOKEN="API_TOKEN"
export TF_VAR_ssh_public_key="ssh-ed25519 ..." # required
export TF_VAR_ssh_public_key_secondary=""  # not required
  1. Source the environment variables:
bash
source .env

Terraform Deployment ​

Initialize the working directory:

bash
terraform init

Preview the planned changes:

bash
terraform plan

Apply the configuration:

bash
terraform apply

View the outputs:

bash
terraform output

Server Configuration ​

Default Settings ​

The terraform.tfvars file contains the default configuration:

hcl
server_base_name = "server"
server_type      = "cx33"
server_image     = "debian-13"
location         = "nbg1"
environment      = "development"
project          = "hello-world"

Server Types ​

Recommended Server Types:

  • cx33: 2 vCPU, 4GB RAM (AMD/Intel, cost-effective)

Locations ​

Supported datacenter locations:

  • nbg1: Nuremberg, Germany
  • fsn1: Falkenstein, Germany
  • hel1: Helsinki, Finland
  • ash: Ashburn, USA
  • hil: Hillsboro, USA

Operating Systems ​

Common image options:

  • debian-13: Debian 12
  • ubuntu-24.04: Ubuntu 24.04 LTS
  • centos-stream-10: CentOS Stream 10
  • fedora-42: Fedora 42

SSH Key Management ​

The configuration supports dual SSH key deployment:

Primary SSH Key ​

Required for server access. Set via environment variable:

bash
export TF_VAR_ssh_public_key="ssh-ed25519..."

Creates resource named: {project}-primary-ssh-key

Secondary SSH Key ​

Optional for team access or backup. Set via environment variable:

bash
export TF_VAR_ssh_public_key_secondary="ssh-rsa..."

Creates resource named: {project}-secondary-ssh-key

Leave empty to skip: export TF_VAR_ssh_public_key_secondary=""

Auto-Incrementing Names ​

The configuration automatically generates server names:

  • Scans existing servers matching the pattern {base_name}-{number}
  • Finds the highest number and increments by one
  • First server: server-1
  • Second server: server-2
  • Continues sequentially

Network Configuration ​

Public Networking ​

All servers are configured with:

  • Public IPv4 address
  • Public IPv6 address
  • Full internet connectivity

Firewall Rules ​

The firewall allows:

  • Inbound: SSH (port 22) from any IP
  • Outbound: All protocols and ports

Server Initialization ​

The user-data.sh script runs on first boot:

bash
#!/bin/bash
apt-get update && apt-get upgrade -y
apt-get install -y curl wget git htop vim ufw
ufw default deny incoming
ufw default allow outgoing
ufw allow ssh
ufw --force enable

Outputs ​

After successful deployment, Terraform provides:

text
server_id = "12345678"
server_name = "server-1"  
server_public_ipv4 = "1.2.3.4"
server_public_ipv6 = "2001:db8::1"
ssh_connection = "ssh root@1.2.3.4"

Cleanup ​

To destroy all created resources:

bash
terraform destroy

State Management ​

Terraform maintains state locally in:

  • terraform.tfstate: Current infrastructure state
  • terraform.tfstate.backup: Previous state backup