Terraform

What is Terraform?

Terraform is an open-source infrastructure as code (IaC) tool created by HashiCorp. It allows you to define and provision infrastructure using a declarative configuration language.

Key Features

• Infrastructure as Code: Define your infrastructure using human-readable configuration files that can be versioned and shared.
• Multi-Cloud Support: Works with multiple cloud providers including AWS, Azure, Google Cloud, and many others.
• Declarative Syntax: Describe what you want your infrastructure to look like, and Terraform figures out how to create it.
• State Management: Tracks the current state of your infrastructure to manage changes effectively.
• Execution Plans: Shows you what changes will be made before actually applying them.

How Terraform Works

1. Write: Define resources in configuration files using HashiCorp Configuration Language (HCL).
2. Plan: Preview the changes Terraform will make to your infrastructure.
3. Apply: Execute the planned changes to provision or modify infrastructure.

Common Use Cases

• Provisioning cloud infrastructure (servers, networks, storage)
• Managing Kubernetes clusters
• Orchestrating multi-tier applications
• Setting up development, staging, and production environments
• Managing DNS records and CDN configurations

Example Configuration

hcl Copyresource "aws_instance" "example" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"

  tags = {
    Name = "ExampleInstance"
  }
}

This simple example shows how to define an AWS EC2 instance using Terraform's declarative syntax.

Here are the important Terraform commands and their descriptions:

• terraform init: Initializes a Terraform working directory by downloading provider plugins and setting up the backend.
• terraform plan: Creates an execution plan showing what changes Terraform will make to your infrastructure without actually applying them.
• terraform apply: Executes the actions proposed in the Terraform plan to create, update, or delete infrastructure resources.
• terraform destroy: Destroys all resources managed by the current Terraform configuration.
• terraform validate: Checks whether the configuration files are syntactically valid and internally consistent.
• terraform fmt: Formats Terraform configuration files to a canonical format and style.
• terraform show: Displays the current state or a saved plan in a human-readable format.
• terraform state: Advanced state management command for viewing and manipulating the Terraform state file.
• terraform output: Displays the output values from your Terraform state.
• terraform import: Imports existing infrastructure into Terraform state so it can be managed by Terraform.
• terraform workspace: Manages multiple workspaces for organizing infrastructure into separate state files.
• terraform refresh: Updates the state file to match the real-world infrastructure.

Main mantra for terraform syntax

{

    <arguments>

}

• terraform apply -var “instance_name = YetAnotherName”

Variable types -

List, Map, Set

example-

Zebra@2025Secure!