Use the Terraform Provider

The Constellation Terraform provider allows to manage the full lifecycle of a Constellation cluster (namely creation, upgrades, and deletion) via Terraform. The provider is available through the Terraform registry and is released in lock-step with Constellation releases.

Prerequisites

• a Linux operating system (ARM64/AMD64)
• a Terraform installation of version v1.4.4 or above

Quick setup

This example shows how to set up a Constellation cluster with the reference IAM and infrastructure setup. This setup is also used when creating a Constellation cluster through the Constellation CLI. You can either consume the IAM / infrastructure modules through a remote source (recommended) or local files. The latter requires downloading the infrastructure and IAM modules for STACKIT from terraform-modules.zip on the Constellation release page and placing them in the Terraform workspace directory.

1. Create a directory (workspace) for your Constellation cluster.

   mkdir constellation-workspace cd constellation-workspace

2. Use the example configuration for using the Constellation Terraform provideror create a main.tf file and fill it with the resources you want to create. The Constellation Terraform provider documentation offers thorough documentation on the resources and their attributes.
3. Initialize the providers and apply the Terraform configuration.

   terraform init
   terraform apply

   Optionally, you can prefix the terraform apply command with TF_LOG=INFO to collect Terraform logs while applying the configuration. This may provide helpful output in debugging scenarios.
4. Connect to the cluster.

   terraform output -raw kubeconfig > constellation-admin.conf
   export KUBECONFIG=$(realpath constellation-admin.conf)

Bringing your own infrastructure

Instead of using the example infrastructure used in the quick setup, you can also provide your own infrastructure. If you need a starting point for a custom infrastructure setup, you can download the infrastructure / IAM Terraform modules for STACKIT from the Constellation GitHub releases. You can modify and extend the modules per your requirements, while keeping the basic functionality intact. The module contains:

• STACKIT: cloud resources the cluster runs on
• IAM/STACKIT: IAM resources used within the cluster

When upgrading your cluster, make sure to check the Constellation release notes for potential breaking changes in the reference infrastructure / IAM modules that need to be considered.