All about terraform Modules – how to Create & Publish your own modules – 100 days of Cloud: Day 21

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DAY 21 – All about terraform Modules – Create & Publish your own modules – Day Twenty One

100 days of Cloud on GitHub – Read On iCTPro.co.nz – Read on Dev.to

Using modules

Public Modules

Terraform registry
Syntax NameSpace/Name/Provider
initiate via terraform init

Private Modules

terraform cloud
Syntax Hostname/NameSpace/Name/Provider
initiate via terraform login

Publishing Modules

Public Modules

Modules are published on to github. It have to be named with a specific name pattern as well.
ex:- lets say you are creating a modules for AWS VPC then module have to be named terraform-aws-vpc. You publish you module to terraform registry via GitHub account.

Some Features

Supports versioning
Generate document
version history
Show example
available readme.md

Verified Modules

Verified modules are reviewed by HashiCorp and actively maintained by contributors to stay up-to-date and compatible with both Terraform and their respective providers.

The verified badge appears next to modules that are published by a verified source.

Standard Module Structure

Lets get an idea of the structure

main.tf – This must exists on the root directory. In other words this file is the entry point for your module.
variables.tf , Outputs.tf– All variables and outputs should have one or two sentence descriptions that explain their purpose. (Variables that can be passed, outputs are output values)
readme.md – description in a readme file.
LICENSE – The license under which this module is available
Nested Module – Optional, must be inside the modules/ directory

Structure example

$ tree complete-module/
.
├── README.md
├── main.tf
├── variables.tf
├── outputs.tf
├── ...
├── modules/
│   ├── nestedA/
│   │   ├── README.md
│   │   ├── variables.tf
│   │   ├── main.tf
│   │   ├── outputs.tf
│   ├── nestedB/
│   ├── .../
├── examples/
│   ├── exampleA/
│   │   ├── main.tf
│   ├── exampleB/
│   ├── .../

Building your own Modueles

Lets use VSCode (Visual Studio Code) for this project

Make sure you have Terraform Visual Studio Code Extension is installed.

File Structure

Lets create a new directory and Name it as terraform-aws-ec2
Building the file structure.
- Lets create file main.tf
Now create a sub folder named terraform-aws-ec2module-tutorial and create these files also outputs.tf, variables.tf, readme.md, LICENSE
- I am Using GitHub Terraform AWS modules by Anton Babenko (The 🪄 Magic 🔮Man) for reference for this project.

Check out below links for contents in files
- LICENSE
- main.tf
- outputs.tf
- README.md
- userdata.yaml
- variables.tf
- versions.tf
- .gitignore

Here we are going to build a module to create EC2 preloaded with APACHE and publish it to the terraform registry with GitHub.

Lets Build a Module

Once you created and copy pasted all the codes as above, we will create an terraform module to create an EC2 instance.

An EC2 APACHE server

Goal of the module is to create a EC2 instance with Apache installed in that.

Create a Public GitHub repo

Name the repo as terraform-aws-ec2module-tutorial.
On your project folder cd in to terraform-aws-ec2module-tutorial.
Initialise, add all, commit and push the code.
Add a version tag.

git tag v1.0.0
git push --tags

Connecting to Terraform Registry

Go to Terraform Registry
click on to sign-in, then click to Sign in with GitHub
Authorize hashicrop Sign in.
Go and select publish module
Select our module, agree to terms of use and click Publish Module .
🎉Congratulations🎉 you have successfully published your module to terraform registry