12. Modules

Introduction

• Modules are containers for multiple resources that are used together. A module consists of a collection of .tf and/or .tf.json files kept together in a directory

• Modules are main way to package and reuse resource configurations with terraform

• Input variables are passed in via module block

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Types

1. Root Module

Default module containing all .tf files in main working directory

2. Child Module

A sepearte external module referred to from a .tf file

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Module Sources

Local paths

module "web-app" {
  source = "../web-app"
}

Terraform Registry

module "web-app" {
  source = "hashicorp/consul/aws"
  version = "0.1.0"
}

Github

• via HTTPS

• via SSH

• Generic i.e source = "git::ssh//[e-mail]/storage.git"

Others

• Bitbucket

• Generic Git

• HTTP URLs

• S3 buckets

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Good Module Characteristics

• Raise abstraction level from base resource types

• Group resources in a logical fashion

• Exposes input variables to allow necessary customization + composition

• Provide useful defaults

• Returns outputs to make further integrations possible

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