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Terraform Beginner Bootcamp 2023 - Week 0

Semantic Versioning

This project is going utilize semantic versioning for its tagging. semver.org

The general format:

MAJOR.MINOR.PATCH, eg. 1.0.1

  • MAJOR version when you make incompatible API changes
  • MINOR version when you add functionality in a backward compatible manner
  • PATCH version when you make backward compatible bug fixes

Install the Terraform CLI

Considerations with the Terraform CLI changes

The Terraform CLI installation instructions have changed due to gpg keyring changes. So we needed refer to the latest install CLI instructions via Terraform Documentation and change the scripting for install.

Install Terraform CLI

Considerations for Linux Distribution

This project is built against Ubunutu. Please consider checking your Linux Distrubtion and change accordingly to distrubtion needs.

How To Check OS Version in Linux

Example of checking OS Version:

$ cat /etc/os-release

PRETTY_NAME="Ubuntu 22.04.3 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.3 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy

Refactoring into Bash Scripts

While fixing the Terraform CLI gpg depreciation issues we notice that bash scripts steps were a considerable amount more code. So we decided to create a bash script to install the Terraform CLI.

This bash script is located here: ./bin/install_terraform_cli

  • This will keep the Gitpod Task File (.gitpod.yml) tidy.
  • This allow us an easier to debug and execute manually Terraform CLI install
  • This will allow better portablity for other projects that need to install Terraform CLI.

Shebang Considerations

A Shebang (prounced Sha-bang) tells the bash script what program that will interpet the script. eg. #!/bin/bash

ChatGPT recommended this format for bash: #!/usr/bin/env bash

  • for portability for different OS distributions
  • will search the user's PATH for the bash executable

https://en.wikipedia.org/wiki/Shebang_(Unix)

Execution Considerations

When executing the bash script we can use the ./ shorthand notiation to execute the bash script.

eg. ./bin/install_terraform_cli

If we are using a script in .gitpod.yml we need to point the script to a program to interpert it.

eg. source ./bin/install_terraform_cli

Linux Permissions Considerations

In order to make our bash scripts executable we need to change linux permission for the fix to be exetuable at the user mode.

chmod u+x ./bin/install_terraform_cli

alternatively:

chmod 744 ./bin/install_terraform_cli

https://en.wikipedia.org/wiki/Chmod

Gitpod Lifecycle

We need to be careful when using the Init because it will not rerun if we restart an existing workspace.

https://www.gitpod.io/docs/configure/workspaces/tasks

Working Env Vars

env command

We can list out all Enviroment Variables (Env Vars) using the env command

We can filter specific env vars using grep eg. env | grep AWS_

Setting and Unsetting Env Vars

In the terminal we can set using export HELLO='world

In the terrminal we unset using unset HELLO

We can set an env var temporarily when just running a command

HELLO='world' ./bin/print_message

Within a bash script we can set env without writing export eg.

#!/usr/bin/env bash

HELLO='world'

echo $HELLO

Printing Vars

We can print an env var using echo eg. echo $HELLO

Scoping of Env Vars

When you open up new bash terminals in VSCode it will not be aware of env vars that you have set in another window.

If you want to Env Vars to persist across all future bash terminals that are open you need to set env vars in your bash profile. eg. .bash_profile

Persisting Env Vars in Gitpod

We can persist env vars into gitpod by storing them in Gitpod Secrets Storage.

gp env HELLO='world'

All future workspaces launched will set the env vars for all bash terminals opened in thoes workspaces.

You can also set en vars in the .gitpod.yml but this can only contain non-senstive env vars.

AWS CLI Installation

AWS CLI is installed for the project via the bash script ./bin/install_aws_cli

Getting Started Install (AWS CLI) AWS CLI Env Vars

We can check if our AWS credentials is configured correctly by running the following AWS CLI command:

aws sts get-caller-identity

If it is succesful you should see a json payload return that looks like this:

{
    "UserId": "AIEAVUO15ZPVHJ5WIJ5KR",
    "Account": "123456789012",
    "Arn": "arn:aws:iam::123456789012:user/terraform-beginner-bootcamp"
}

We'll need to generate AWS CLI credits from IAM User in order to the user AWS CLI.

Terraform Basics

Terraform Registry

Terraform sources their providers and modules from the Terraform registry which located at registry.terraform.io

  • Providers is an interface to APIs that will allow to create resources in terraform.
  • Modules are a way to make large amount of terraform code modular, portable and sharable.

Randon Terraform Provider

Terraform Console

We can see a list of all the Terrform commands by simply typing terraform

Terraform Init

At the start of a new terraform project we will run terraform init to download the binaries for the terraform providers that we'll use in this project.

Terraform Plan

terraform plan

This will generate out a changeset, about the state of our infrastructure and what will be changed.

We can output this changeset ie. "plan" to be passed to an apply, but often you can just ignore outputting.

Terraform Apply

terraform apply

This will run a plan and pass the changeset to be execute by terraform. Apply should prompt yes or no.

If we want to automatically approve an apply we can provide the auto approve flag eg. terraform apply --auto-approve

Terraform Destroy

teraform destroy This will destroy resources.

You can alos use the auto approve flag to skip the approve prompt eg. terraform apply --auto-approve

Terraform Lock Files

.terraform.lock.hcl contains the locked versioning for the providers or modulues that should be used with this project.

The Terraform Lock File should be committed to your Version Control System (VSC) eg. Github

Terraform State Files

.terraform.tfstate contain information about the current state of your infrastructure.

This file should not be commited to your VCS.

This file can contain sensentive data.

If you lose this file, you lose knowning the state of your infrastructure.

.terraform.tfstate.backup is the previous state file state.

Terraform Directory

.terraform directory contains binaries of terraform providers.

Issues with Terraform Cloud Login and Gitpod Workspace

When attempting to run terraform login it will launch bash a wiswig view to generate a token. However it does not work expected in Gitpod VsCode in the browser.

The workaround is manually generate a token in Terraform Cloud

https://app.terraform.io/app/settings/tokens?source=terraform-login

Then create open the file manually here:

touch /home/gitpod/.terraform.d/credentials.tfrc.json
open /home/gitpod/.terraform.d/credentials.tfrc.json

Provide the following code (replace your token in the file):

{
  "credentials": {
    "app.terraform.io": {
      "token": "YOUR-TERRAFORM-CLOUD-TOKEN"
    }
  }
}

We have automated this workaround with the following bash script bin/generate_tfrc_credentials