Terraform – Infrastructure as Code fuer AWS und Azure 2025

Terraform Grundkonzepte

Terraform-Grundprinzipien:
  Deklarativ: "Was soll existieren?" (nicht "wie baue ich es auf?")
  Provider: Plugins fuer Cloud-APIs (AWS, Azure, GCP, etc.)
  State: Zustand der echten Infrastruktur gespeichert
  Plan: Vorschau was sich aendern wird
  Apply: Aenderungen durchfuehren

Workflow:
  terraform init    → Provider herunterladen
  terraform plan    → Vorschau anzeigen
  terraform apply   → Ausfuehren
  terraform destroy → Alles loeschen

Dateien:
  main.tf      → Hauptkonfiguration
  variables.tf → Eingabevariablen
  outputs.tf   → Ausgabewerte
  providers.tf → Provider-Konfiguration
  backend.tf   → State-Backend

Terraform installieren

# Ubuntu/Debian
wget -O- https://apt.releases.hashicorp.com/gpg | gpg --dearmor |
    tee /usr/share/keyrings/hashicorp-archive-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main" |
    tee /etc/apt/sources.list.d/hashicorp.list
apt update && apt install terraform

# macOS
brew tap hashicorp/tap && brew install hashicorp/tap/terraform

# Version pruefen
terraform version

Erstes Projekt: Azure VM

# providers.tf
terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~> 3.0"
    }
  }
  backend "azurerm" {
    resource_group_name  = "rg-terraform-state"
    storage_account_name = "tfstate12345"
    container_name       = "tfstate"
    key                  = "prod.terraform.tfstate"
  }
}

provider "azurerm" {
  features {}
}

# main.tf
resource "azurerm_resource_group" "main" {
  name     = "rg-meine-app"
  location = "Germany West Central"
}

resource "azurerm_virtual_network" "main" {
  name                = "vnet-main"
  address_space       = ["10.0.0.0/16"]
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
}

resource "azurerm_subnet" "internal" {
  name                 = "subnet-internal"
  resource_group_name  = azurerm_resource_group.main.name
  virtual_network_name = azurerm_virtual_network.main.name
  address_prefixes     = ["10.0.1.0/24"]
}

resource "azurerm_linux_virtual_machine" "app" {
  name                = "vm-app-server"
  resource_group_name = azurerm_resource_group.main.name
  location            = azurerm_resource_group.main.location
  size                = "Standard_B2s"
  admin_username      = "azureuser"

  network_interface_ids = [azurerm_network_interface.main.id]

  admin_ssh_key {
    username   = "azureuser"
    public_key = file("~/.ssh/id_rsa.pub")
  }

  os_disk {
    caching              = "ReadWrite"
    storage_account_type = "Premium_LRS"
  }

  source_image_reference {
    publisher = "Canonical"
    offer     = "0001-com-ubuntu-server-jammy"
    sku       = "22_04-lts"
    version   = "latest"
  }
}

Terraform Plan und Apply

# Azure-Login
az login

# Terraform initialisieren
terraform init

# Plan erstellen (zeigt was passiert)
terraform plan -out=tfplan

# Apply ausfuehren
terraform apply tfplan

# Aenderung: VM-Groesse aendern in main.tf
# size = "Standard_B4ms"
terraform plan  # zeigt: ~azurerm_linux_virtual_machine.app will be updated

# Destroy
terraform destroy

FAQ

Was ist der Unterschied zwischen Terraform und Ansible?
Terraform: Infrastruktur provisionieren (VMs, Netzwerke, Services erstellen). Ansible: Konfiguration verwalten (Pakete installieren, Dateien konfigurieren). Optimal: Terraform + Ansible zusammen.

Fazit

Terraform ist der Standard fuer Cloud-IaC: Provider fuer alle grossen Clouds, State-Management und Plan-Preview machen Infrastruktur-Aenderungen reproduzierbar und sicher.

Terraform und IaC fuer KMU in Heidelberg, Mannheim und der Rhein-Neckar-Region. Beratung anfragen.