Terraform module: Deploy your infrastructure in one click

Terraform module: Deploy your infrastructure in one click Deploy • Jules Martin • 25/07/22 • 10 min read

We are going to cover some new concepts of Terraform to help you manage your infrastructure easily. As we are continuously working on new products and our Terraform provider, I’m also excited to cover new products that will strengthen your architecture.

First, we will use our first repository as a base to set up our new infrastructure. We will transform our main directory into a sub-section to have multiple modules inside one big Scaleway module. This structure opens up the possibility to deploy all the infrastructure you need in one click. Then, if you don’t need products (like a database for example), you will simply not call this sub-module in your main.tf.

You can find this second and more developed repository right here .

Before starting on the project, you need to have an account and your credentials all set up. You’ll also need to install Terraform on the server you are using, or locally, using the last version of the Scaleway Terraform provider .

First, what is a module?

Hashicorp documentation defines a module as a container for multiple resources used together. More specifically, a module is a small portion of your code that you put inside a specific repository to use again later. It will allow you to:

Give a clearer vision of your code and how to use it;

deploy the same piece of code multiple times in a second;

call the same code into a different configuration (launching multiple servers with different sizing).

In this tutorial, I will turn one specific product (in this case, an instance) and turn it into a module. Then, we will deploy our infrastructure.

Second, what are we going to deploy?

We are going to deploy the basics of infrastructure to allow you to build any kind of application: an instance, a database, a Kubernetes cluster, a load balancer. We’ll wrap everything in a private network, behind a public gateway, for safety reasons. However, the integration of the Kubernetes cluster inside a VPC is not done yet, so it will be completed outside of our private network.

Schema of the infrastructure we will deploy

A new architecture

The first change is that we will modify the tree structure of the repository. Instead of having everything on the same level and one file per product/feature, we are going to divide our resources into sub-directory, with the same layout each time.

We are going from this:

To this:

tree ├── LICENSE ├── README.md ├── Terraform_Module_Scaleway_Schema.webp ├── backend.tf ├── main.tf ├── module │ ├── database │ │ ├── main.tf │ │ ├── outputs.tf │ │ ├── provider.tf │ │ └── variables.tf │ ├── instance │ │ ├── main.tf │ │ ├── outputs.tf │ │ ├── provider.tf │ │ └── variables.tf │ ├── kapsule │ │ ├── main.tf │ │ ├── outputs.tf │ │ ├── provider.tf │ │ └── variables.tf │ ├── loadbalancer │ │ ├── main.tf │ │ ├── outputs.tf │ │ ├── provider.tf │ │ └── variables.tf │ └── vpc │ ├── main.tf │ ├── outputs.tf │ ├── provider.tf │ └── variables.tf ├── provider.tf ├── terraform .tfvars └── variables.tf 6 directories, 28 files CopyContentIcon Copy code Although it looks more complicated at first glance, this is an easier and more scalable way to deploy and maintain your infrastructure. In fact, your root main.tf will be only used to call the resources that you need by sourcing the right module.

Your variables and outputs will be linked to your dedicated resources in the right module. And if you need global variables, you will still have the root variables.tf file.

Finally, if you want to deploy more/new resources, you simply have to create a new sub-directory and call it as many times as you need.

Turning a Terraform repository into a module

Let’s take a deep dive into our new main.tf, where all the logic is going to be gathered.

We went from this:

resource “scaleway_instance_ip” “public_ip” { } resource “scaleway_instance_volume” “scw - instance” { size_in_gb = 30 type = “l_ssd” } resource “scaleway_instance_server” “scw - instance” { type = “ DEV1 - L ” image = “ubuntu_focal” tags = [ “terraform instance” , “scw - instance” ] ip_id = scaleway_instance_ip . public_ip . id additional_volume_ids = [ scaleway_instance_volume . scw - instance . id ] root_volume { # The local storage of a DEV1 - L instance is 80 GB , subtract 30 GB from the additional l_ssd volume , then the root volume needs to be 50 GB . size_in_gb = 50 } } CopyContentIcon Copy code to this:

module "instance" { source = "./module/instance" instance_size_in_gb = var . instance_size_in_gb instance_type = var . instance_type instance_image = var . instance_image volume_size_in_gb = var . volume_size_in_gb volume_type = var . volume_type tags = var . tags private_network_id = module . vpc . private_network_id } module "database" { source = "./module/database" rdb_instance_node_type = var . rdb_instance_node_type rdb_instance_engine = var . rdb_instance_engine rdb_is_ha_cluster = var . rdb_is_ha_cluster rdb_disable_backup = var . rdb_disable_backup rdb_instance_volume_type = var . rdb_instance_volume_type rdb_instance_volume_size_in_gb = var . rdb_instance_volume_size_in_gb rdb_user_root_password = var . rdb_user_root_password rdb_user_scaleway_db_password = var . rdb_user_scaleway_db_password instance_ip_addr = module . instance . instance_ip_addr private_network_id = module . vpc . private_network_id user_name = var . user_name zone = var . zone region = var . region env = var . env } module "kapsule" { source = "./module/kapsule" kapsule_cluster_version = var . kapsule_cluster_version kapsule_pool_size = var . kapsule_pool_size kapsule_pool_min_size = var . kapsule_pool_min_size kapsule_pool_max_size = var . kapsule_pool_max_size kapsule_pool_node_type = var . kapsule_pool_node_type cni = var . cni zone = var . zone region = var . region env = var . env } module "loadbalancer" { source = "./module/loadbalancer" lb_size = var . lb_size inbound_port = var . inbound_port forward_port = var . forward_port forward_protocol = var . forward_protocol private_network_id = module . vpc . private_network_id zone = var . zone region = var . region env = var . env } module "vpc" { source = "./module/vpc" public_gateway_dhcp = var . public_gateway_dhcp public_gateway_type = var . public_gateway_type bastion_port = var . bastion_port zone = var . zone region = var . region env = var . env } CopyContentIcon Copy code As you can see, we deleted the instance resources from our previous…