4. Terraform Modules & Workspaces

Question 1

Terraform Registry

• The Terraform Registry is a repository of modules written by the Terraform community.
• The registry can help you get started with Terraform more quickly
• If we intend to use a module, we need to define the path where the module files are present.
• The module files can be stored in multiple locations, some of these include:
  
  • Local Path
  • GitHub
  • Terraform Registry
  • S3 Bucket
  • HTTP URLs

Question 2

Verified Modules in Terraform Registry​

• Within Terraform Registry, you can find verified modules that are maintained by various third-party vendors.
• These modules are available for various resources like AWS VPC, RDS, ELB, and others
• 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 blue verification badge appears next to modules that are verified.
• Module verification is currently a manual process restricted to a small group of trusted HashiCorp partners.

Question 3

Using Registry Modules in Terraform

• To use Terraform Registry module within the code, we can make use of the source argument that contains the module path.
• The public registry uses a three-part format, and private modules use a four-part format.
  
  • < NAMESPACE > / < MODULE NAME > / < PROVIDER>
  • < HOSTNAME > / < ORGANIZATION > / < MODULE NAME > / < PROVIDER >
• Below code references to the EC2 Instance module within terraform registry.

module “ec2-instance” {

source = “terraform-aws-modules/ec2-instance/aws”

version = “2.13.0”

# insert the 10 required variables here

}

Question 4

Terraform Workspaces

• Terraform allows us to have multiple workspaces, with each of the workspaces we can have a different set of environment variables associated
• Terraform starts with a single workspace named “default”.
• This workspace is special both because it is the default and also because it cannot ever be deleted.
• If you’ve never explicitly used workspaces, then you’ve only ever worked on the “default” workspace.
• Workspaces are managed with the terraform workspace set of commands.
• To create a new workspace and switch to it, you can use terraform workspace new; to switch workspaces you can use terraform workspace select; etc.
• Custom workspace state file location: terraform.tfstate.d
• Workspaces, managed with the terraform workspace command, isn’t the same thing as Terraform Cloud’s workspaces. Terraform Cloud workspaces act more like completely separate working directories.

Question 5

Terraform Workspaces Commands

Usage: terraform workspace <subcommand> [options] [args]</subcommand>

• list
• select
• new
• delete
• show