Terraform Basics

Question 1

The core Terraform workflow consists of three stages:

Answer 1

Write
Plan
Apply

Question 2

The write stage of the Terraform Workflow

Answer 2

First Step in the workflow.

Define infra in config files

Question 3

The Review stage of the Terraform workflow

Answer 3

2nd stage in workflow after Write

Review the changes Terraform will make to your infra

Question 4

The Apply stage in the workflow

Answer 4

Final stage in the workflow

Terraform provisions your infra and updates the state file

Question 5

State File

Answer 5

Keeps track of your infrastructure.

Used to determined the changes to make to your infra.

Question 6

Modules

Answer 6

Reusable configuration components called modules that define configurable collections of infra.

Question 7

To deploy infrastructure with Terraform (5 Steps):

Answer 7

Scope - Identify the infrastructure for your project.
Author - Write the configuration for your infrastructure.
Initialize - Install the plugins Terraform needs to manage the infrastructure.
Plan - Preview the changes Terraform will make to match your configuration.
Apply - Make the planned changes.

Question 8

Configuration file: The Terraform Block

Answer 8

terraform {} block contains Terraform settings, including the required providers Terraform will use to provision your infrastructure.

Question 9

Configuration File: The provider block

Answer 9

The provider block configures the specified provider

A provider is a plugin that Terraform uses to create and manage your resources. You can define multiple provider blocks in a Terraform configuration to manage resources from different providers.

provider “azurerm” {
features {}
}

Question 10

Configuration File: Resources Block

Answer 10

Use resource blocks to define components of your infrastructure.

Resource blocks have two strings before the block: the resource type and the resource name.

Together, the resource type and resource name form a unique ID for the resource.

resource “azurerm_resource_group” “rg” {
name = “myTFResourceGroup”
location = “westus2”
}

Question 11

Terraform State

Answer 11

Terraform must store state about your managed infrastructure and configuration.

This state is stored by default in a local file named “terraform.tfstate”, but it can also be stored remotely, which works better in a team environment.

Question 12

What “Day 0” and “Day 1” activities?

Answer 12

“Day 0” code provisions and configures your initial infrastructure.

“Day 1” refers to OS and application configurations you apply after you’ve initially built your infrastructure.

Question 13

What are providers?

Answer 13

A provider is a plugin that Terraform uses to translate the API interactions with the service. A provider is responsible for understanding API interactions and exposing resources.

Question 14

How to configure a provider?

Answer 14

With a provider block

provider “google” {
project = “acme-app”
region = “us-central1”
}

Question 15

meta-arguments defined by Terraform and available for all provider blocks?

Answer 15

version: Constraining the allowed provider versions
alias: using the same provider with different configurations for different resources

Question 16

What happens during provider initialization?

Answer 16

Terraform downloads and installs the plugin so that it can later be executed.

Question 17

How to initialize any provider?

Answer 17

terraform init

Question 18

how to configure multiple provider instances?

Answer 18

alias

You can optionally define multiple configurations for the same provider, and select which one to use on a per-resource or per-module basis.

# The default provider configuration
provider "aws" {
  region = "us-east-1"
}

# Additional provider configuration for west coast region
provider "aws" {
  alias  = "west"
  region = "us-west-2"
}

Question 19

Alternate providers have been defined using alias, how to specify which provider to resources?

Answer 19

by default, resources infer the provider from resource id.

use provider argument to override

resource “aws_instance” “foo” {
provider = aws.west

  # ...
}

Question 20

Installing third party plugins

Answer 20

Cannot be installed using terraform init.

Must be manually installed

Question 21

Provider naming scheme

Answer 21

terraform-provider-[NAME]_vX.Y.Z