Terraform + Terragrunt workshop

Welcome to the Terraform + Terragrunt workshop! This repository contains a
guide on how to use Terraform to deploy and manage Juju models. Additionally,
this shows how to minimize deduplication of deployment plans with Terragrunt.

This guide is a partial adaptation of the Terralith to Terragrunt guide.
You should read that guide if you want more extensive explanations about the concepts
used in this guide.

Getting started

To go through the workshop, you'll require two things:

A working Juju installation.
LXD exposed as a Juju cloud.

Set up

Installing Tenv

This is a version manager for OpenTofu, Terraform, Terragrunt, and other TF-related
tools. We will use it to easily install and manage the versions of OpenTofu and
Terragrunt

sudo snap install tenv

Then, install OpenTofu + Terragrunt with the command

tenv opentofu install 1.10.6 # OpenTofu
tenv tg install 0.93.1 # Terragrunt

If you are rate limited by Github, you might need to generate a personal access token
in https://github.com/settings/personal-access-tokens, then set the TENV_GITHUB_TOKEN
with:

export TENV_GITHUB_TOKEN=<my-token>

Level 1 - Basic infrastructure

Checkout the level-1 branch:

git checkout level-1

Then run the following commands to initialize and deploy the Terraform plans:

tofu -chdir=live init
tofu -chdir=live apply

After checking that all the resources look good, just type "yes" and enter to
create all the defined resources.

Level 2 - Terraform modules

Checkout the level-2 branch:

git checkout level-2

And apply the newly refactored modules.

tofu -chdir=live init
tofu -chdir=live apply

If everything goes according to plan, OpenTofu should report:

Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

Level 3 - Two deployments

Checkout the level-3 branch:

git checkout level-3

And refresh the old development deployment:

tofu -chdir=live/dev init
tofu -chdir=live/dev apply

If everything goes according to plan, OpenTofu should report:

Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

Similarly, apply the newly created production deployment:

tofu -chdir=live/prod init
tofu -chdir=live/prod apply

This will deploy a "production" plan very similar to the "development" plan.

Level 4 - Terragrunt

Run Terragrunt against all subdirectores with a terragrunt.hcl file:

terragrunt run --all plan

If everything is correct, this should output 0 changes in our two deployments.

It can also be run in directories matching a pattern:

terragrunt run --all --queue-include-dir dev plan # Only runs in dev

jedel1043/terragrunt-workshop