Terraform

Terraform Configuration Files

• Terraform configuration files use .tf or .tf.json file extensions.

Terraform Initialization

• The terraform init command is used to initialize a Terraform directory.

HCL in Terraform

• HCL (HashiCorp Configuration Language) is used to write Terraform configuration files.

Variable Types in Terraform

• Terraform supports several variable types, including:
  • String
  • Number
  • Bool
  • List
  • Map
  • Object
  • Null

Terraform.tfvars File

• The terraform.tfvars file is used to set input variables for Terraform configurations.

Main Files in a Terraform Module

• The main files in a typical Terraform module include:
  • main.tf
  • variables.tf
  • outputs.tf

Terraform Actions

• Terraform can perform three main actions on its controlled environment:
  • Create
  • Update
  • Delete

Declaring Variables in Terraform

• Declaring variables in Terraform allows users to:
  • Store and reuse values
  • Externalize configuration

Description Field in Variable Block

• The description field in a variable block is used to provide a human-readable description of the variable.

Precedence of Variable Values

• When setting variable values in Terraform, the following order of precedence applies:
  • Environment variables
  • terraform.tfvars file
  • *.auto.tfvars files
  • Command-line flags

Terraform Outputs

• Terraform outputs can be used to:
  • Share data between modules
  • Display information to the user
• Statements about Terraform outputs:
  • They are used to expose values from a Terraform module.
  • They can be accessed using the terraform output command.

Sensitive Argument in Terraform Outputs

• The sensitive argument in Terraform outputs is used to:
  • Hide sensitive output values

Terraform Resources

• Terraform resources represent infrastructure objects, such as:
  • Virtual machines
  • Databases
  • Network interfaces

Depends_on Field in Terraform Resources

• The depends_on field in Terraform resources allows users to:
  • Specify resource dependencies

TFState File

• The tfstate file is used to store the current state of the Terraform-managed infrastructure.

Terraform Output Values

• Terraform output values can help users see:
  • Values of output variables
  • Resource attributes

Output Block in Terraform Modules

• The purpose of the output block in Terraform modules is to:
  • Expose values from a Terraform module

CLI Output using Terraform Outputs

• Terraform outputs can be used to display information in the CLI output, including:
  • Strings
  • Numbers
  • Lists
  • Maps

Resource Keyword in Terraform Configuration Files

• After the resource keyword in Terraform configuration files, users can specify:
  • Resource types (e.g., aws_instance)
  • Resource names

Terraform Resources

• Terraform resources allow users to declare:
  • Infrastructure components
  • Their properties