TERRAFORM

Terraform is an open-source infrastructure as code (IaC) tool developed by HashiCorp. It allows you to define and provision data center infrastructure using a high-level configuration language known as HashiCorp Configuration Language (HCL), or optionally JSON. Terraform is designed to create, manage, and update infrastructure resources such as virtual machines, networks, and storage in a reproducible and automated manner.

WHY USE TERRAFORM:

1. Infrastructure as Code (IaC):
• Terraform enables you to write code to define and manage your infrastructure. This code can be versioned, reviewed, and shared, making your infrastructure setup transparent and consistent.
2. Declarative Configuration:
• You declare the desired state of your infrastructure, and Terraform takes care of the rest. For example, if you need an AWS EC2 instance, you specify it in the configuration, and Terraform ensures it is created as described.
3. Resource Management:
• Terraform manages the lifecycle of infrastructure resources. This includes creating, updating, and deleting resources as specified in the configuration files.
4. Execution Plans:
• Before applying changes, Terraform generates an execution plan that shows what actions will be taken to reach the desired state. This helps in understanding and validating the changes before they are applied.
5. State Management:
• Terraform keeps track of the state of your infrastructure using a state file. This file is used to map your configuration to the real-world resources, ensuring consistency and enabling Terraform to determine what changes need to be made.
6. Provisioning Across Multiple Providers:
• Terraform supports a wide range of cloud providers and services, including AWS, Azure, Google Cloud, Kubernetes, and many others. This allows you to manage infrastructure across multiple platforms using a single tool.

7.      Standardize configurations

Terraform supports reusable configuration components called modules that define configurable collections of infrastructure, saving time and encouraging best practices. You can use publicly available modules from the Terraform Registry, or write your own.

The core Terraform workflow consists of three stages:

·        Terraform Init

            Terraform init is the command used to initialize a Terraform working directory. This command              sets up the environment and prepares it for further actions.

·         Plan: Terraform creates an execution plan describing the infrastructure it will create, update, or destroy based on the existing infrastructure and your configuration.

·         Apply: On approval, Terraform performs the proposed operations in the correct order, respecting any resource dependencies. For example, if you update the properties of a VPC and change the number of virtual machines in that VPC, Terraform will recreate the VPC before scaling the virtual machines.

UNDERSTANDING TERRAFORM

Imagine You are Building a House

1. Blueprints (Terraform Configuration Files):
• Just like you need blueprints to build a house, you use Terraform to write down the plans for your infrastructure. This plan includes all the details about what your infrastructure should look like, such as the number of servers (like rooms), databases (like plumbing), and networking settings (like electrical wiring).
2. The Builder (Terraform Tool):
• Terraform is like a smart builder who reads your blueprints and constructs the house exactly as you've planned. It takes care of all the details and makes sure everything is put together correctly.
3. Step-by-Step Plan (Execution Plan):
• Before the builder starts working, they show you a detailed plan of what they will do. This is Terraform’s "execution plan," which tells you what changes it will make to your infrastructure.
4. Construction (Applying Changes):
• Once you approve the plan, the builder starts constructing your house. Similarly, when you run terraform apply, Terraform creates or updates your infrastructure based on the blueprint.
5. State of the House (State Management):
• Terraform keeps track of the current state of your house. If you want to make changes later, it knows exactly what the house looks like now and what needs to be changed to match the new blueprints.
6. Multiple Builders (Providers):
• Terraform can work with many different builders (cloud providers) like AWS, Google Cloud, and Azure. It can build parts of your house (infrastructure) in different places using the same set of blueprints.

7.     Understanding Modules

In Terraform, modules are like reusable blueprints or building blocks. Instead of writing the same detailed plan for every house you build, you can create a module once and reuse it whenever you need to build that part of the house.