SDI Notes

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13 - Base System ​

Working Code: terraform/base/

The Problem: Clicking through a web console to create servers is slow, unrepeatable, and prone to human error.

The Solution: Terraform lets you define infrastructure as code. Run one command to spin up your stack.

Objective ​

Create a Hetzner server with SSH key authentication (secure) instead of a root password (insecure).

How-to ​

1. Define the Provider ​

Tell Terraform we're using Hetzner Cloud (hcloud) and pass the token variable:

hcl
provider "hcloud" {
  token = var.hcloud_token
}

2. Add your SSH Key ​

Don't use passwords. Upload your public key so the server lets you in automatically:

hcl
resource "hcloud_ssh_key" "default" {
  name       = "julian-ssh-key"
  public_key = file("~/.ssh/id_ed25519.pub")
}

3. Create the Server ​

Link the server to the key you just created:

hcl
resource "hcloud_server" "web" {
  name        = "nginx-server"
  image       = "ubuntu-22.04"
  server_type = "cx11"
  location    = "hel1"
  ssh_keys    = [hcloud_ssh_key.default.id] # <--- Important!
}

4. Create the Firewall ​

Open port 22 (SSH). Default deny is safer than default allow:

hcl
resource "hcloud_firewall" "ssh" {
  name = "ssh-access"
  rule {
    direction = "in"
    protocol  = "tcp"
    port      = "22"
    source_ips = ["0.0.0.0/0", "::/0"]
  }
}

5. Outputs ​

Print the IP at the end so you don't have to go looking for it:

hcl
output "server_ip" {
  value = hcloud_server.web.ipv4_address
}

Verification ​

  1. terraform init (download plugin)
  2. terraform apply (create resources)
  3. SSH in: ssh root@<output_ip> -> Should log in without a password.