1. Terraform workflow using terraform commands

Terraform is an open-source infrastructure as code (IaC) tool developed by HashiCorp. It allows you to define, provision, and manage infrastructure resources across a variety of cloud providers (like AWS, Azure, Google Cloud), as well as other services using a high-level configuration language called HashiCorp Configuration Language (HCL).

Key Components of Terraform

Configuration Files: These are the .tf files where you define the infrastructure you want to provision. This is where you describe the desired state of your resources.

Providers: Providers are plugins that allow Terraform to interact with APIs of cloud providers, services, or platforms like AWS, Azure, Google Cloud, Kubernetes, etc.

Resources: A resource is a component in your infrastructure (e.g., EC2 instances, S3 buckets, databases). Resources are declared in the configuration files.

State: Terraform keeps track of your infrastructure in a state file (terraform.tfstate). This is how Terraform understands what’s been created and what it needs to manage.

Modules: These are reusable, self-contained packages of Terraform code that can be shared and used in multiple configurations.

Terraform Workflow

The general workflow of using Terraform consists of a few key steps: writing the code, initializing the project, planning, applying, and managing the infrastructure.

1. Write Terraform Configuration Files

Create .tf files to define the infrastructure resources you want to provision.

Example: A simple configuration to create an AWS EC2 instance might look like this:

provider "aws" {
  region = "us-west-2"
}

resource "aws_instance" "example" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"
}


You can define multiple resources, outputs, and variables in these configuration files.

2. Initialize Terraform

Run the terraform init command to initialize your Terraform working directory. This command downloads the necessary provider plugins (e.g., AWS provider).

3. Plan Your Infrastructure

Run terraform plan to see what Terraform will do based on the configuration files. It compares the current state (if any) to the desired state and shows what resources will be created, modified, or destroyed.

terraform plan

The plan will not make any changes to your infrastructure. It just shows a preview of what Terraform intends to do.

4. Apply the Configuration

Once you're satisfied with the plan, run terraform apply to provision the infrastructure as defined in the configuration files.

terraform apply

Terraform will prompt for confirmation before applying the changes unless you use -auto-approve flag to skip the confirmation.

Example output:
Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

This will create the EC2 instance in your AWS account (or other resources depending on your configuration).

5. Manage the State

Terraform maintains a state file (terraform.tfstate) that keeps track of all resources it manages. This file should not be modified manually.

You can also store the state remotely (e.g., in an S3 bucket for AWS or in Terraform Cloud) for team collaboration.

6. Modify or Destroy Infrastructure

If you need to make changes to the infrastructure, update the .tf files and re-run terraform apply.

To remove resources, you can run terraform destroy:

terraform destroy

This command will destroy all the resources defined in your configuration.

Terraform Commands in a Typical Workflow

terraform init: Initialize the working directory containing Terraform configuration files.

terraform plan: Generate and show an execution plan (what will be created, changed, or destroyed).

terraform apply: Apply the changes defined in the Terraform configuration to your infrastructure.

terraform destroy: Tear down all the infrastructure that Terraform manages (optional).

terraform validate: Validate the syntax and configuration of your Terraform files.

terraform fmt: Format your Terraform configuration files according to standard style conventions.

Example Workflow

Here’s a step-by-step example of a typical Terraform workflow for provisioning an AWS EC2 instance:

1. Create the configuration file (main.tf):

provider "aws" {
  region = "us-west-2"
}

resource "aws_instance" "example" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = "t2.micro"
}

2 Initialize the directory:

terraform init

3. Plan the infrastructure:

terraform plan

4. Apply the configuration:
terraform apply

Verify the infrastructure (in AWS Console):

Go to the AWS Console and verify the EC2 instance is running.

Modify the configuration (if needed):

Change the instance type or other configurations and run terraform apply again.

Destroy the infrastructure:

terraform destroy

Best Practices

Use Modules: For reusability, abstract common resources into modules.

Remote State Management: Store state files remotely (e.g., in AWS S3 with state locking using DynamoDB) to avoid issues with state file consistency.

Version Control: Always store your Terraform configuration files in a version control system (e.g., Git).

Environment Separation: Use different workspaces or separate directories for different environments (e.g., dev, staging, production).

Conclusion

Terraform provides a streamlined and repeatable approach to managing infrastructure. By defining your infrastructure in code, you can version control, share, and automate infrastructure provisioning across multiple environments. The workflow helps ensure consistency and traceability, making Terraform a powerful tool for infrastructure automation.




Terraform Workflow (Production-Ready)

Write Infrastructure as Code 

Files (Typical Structure)

terraform/
├── main.tf
├── providers.tf
├── variables.tf
├── outputs.tf
├── backend.tf
├── terraform.tfvars
└── modules/

Key Rules

• One concern per file

• No hardcoded values

• Use variables & modules

• Version-pin providers

Initialize Terraform

terraform init

What Happens

• Downloads providers

• Configures backend (remote state)

• Initializes modules

• Creates .terraform/

Re-run when:

• Provider changes

• Backend changes

• Modules change

Format & Validate Code (MANDATORY)

terraform fmt
terraform validate

✔ Enforces standard formatting
✔ Catches syntax errors early

Plan Infrastructure Changes

 terraform plan

Purpose

• Shows what will be created / modified / destroyed

• No changes applied yet

Best Practice

terraform plan -out=tfplan
 

Apply Changes

terraform apply tfplan

terraform apply

What Happens

• Terraform compares desired state vs current state

• Applies only the delta

⚠️ Never apply blindly in production

State Management (CRITICAL)

Terraform State

• Tracks real infrastructure

• Stored in .tfstate

Best Practice

Use remote state:

• AWS S3 + DynamoDB

• Azure Storage Account

• Terraform Cloud

• OCI Object Storage

✔ Enables locking
✔ Prevents corruption
✔ Team collaboration

Change & Drift Management

terraform plan

Refresh State

terraform refresh


Destroy Infrastructure (Careful!)