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Terraform Getting Started

Terraform Getting Started

This repository demonstrates a step-by-step approach to learning Terraform, from basic concepts to advanced features like modules, remote execution, workspaces, and AWS Secrets Manager integration.

Getting Started​

  1. Clone this repository:

    git clone https://github.com/anveshmuppeda/terraform-getting-started.git
    cd terraform-getting-started

  2. Follow the section guides below for each example.

Structure​

.
├── 001-simple-example
├── 002-var-example
├── 003-aws-provider
├── 004-ec2-app
├── 005-simple-module
├── 006-s3-backend
├── 007-remote-exec
├── 008-workspaces
├── 009-awssm-secret
├── 010-rds-awssm
├── 011-rds-awssm-advanced
├── 012-import-example
├── 013-refresh-example
└── README.md

Guide​

001-simple-example​

  • Goal: Introduce the basic Terraform syntax and workflow.
  • Files: main.tf
  • How to use:
    1. cd 001-simple-example
    2. terraform init
    3. terraform apply

002-var-example​

  • Goal: Demonstrate input variables.
  • Files: main.tf, variables.tf
  • How to use:
    1. cd 002-var-example
    2. Edit variables.tf to set variable defaults or use -var on the CLI.
    3. terraform init
    4. terraform apply

003-aws-provider​

  • Goal: Configure the AWS provider and use variables.
  • Files: main.tf, provider.tf, variables.tf, var.tfvars
  • How to use:
    1. cd 003-aws-provider
    2. Set your AWS credentials (via env vars or AWS CLI).
    3. terraform init
    4. terraform apply -var-file=var.tfvars

004-ec2-app​

  • Goal: Deploy a simple EC2 instance with user data.
  • Files: main.tf, provider.tf, variables.tf, terraform.tfvars
  • How to use:
    1. cd 004-ec2-app
    2. Update terraform.tfvars with your AMI ID and key pair.
    3. terraform init
    4. terraform apply

005-simple-module​

  • Goal: Introduce modules for reusable infrastructure.
  • Files: main.tf, modules/ec2-app/main.tf, modules/ec2-app/variables.tf
  • How to use:
    1. cd 005-simple-module
    2. terraform init
    3. terraform apply

006-s3-backend​

  • Goal: Use an S3 backend for remote state storage.
  • Files: backend.tf, main.tf, provider.tf, variables.tf, terraform.tfvars
  • How to use:
    1. cd 006-s3-backend
    2. Edit backend.tf with your S3 bucket details.
    3. terraform init
    4. terraform apply

007-remote-exec​

  • Goal: Use remote-exec and file provisioners to configure EC2 after launch.
  • Files: main.tf, index.html, modules/ec2-app/main.tf, modules/ec2-app/variables.tf
  • How to use:
    1. cd 007-remote-exec
    2. Update variables and index.html as needed.
    3. terraform init
    4. terraform apply

008-workspaces​

  • Goal: Manage multiple environments using workspaces and variable files.
  • Files: main.tf, variables.tf, dev.tfvars, staging.tfvars, prod.tfvars, modules/ec2-app/main.tf, modules/ec2-app/variables.tf
  • How to use:
    1. cd 008-workspaces
    2. Create/select a workspace:
      terraform workspace new dev
      terraform workspace select dev
    3. Apply with environment-specific variables:
      terraform apply -var-file=dev.tfvars
    4. Repeat for staging and prod as needed.

009-awssm-secret​

  • Goal: Use AWS Secrets Manager to inject secrets into your Terraform-managed infrastructure.
  • Files: main.tf, variables.tf, terraform.tfvars, modules/ec2-app/main.tf, modules/ec2-app/variables.tf
  • How to use:
    1. cd 009-awssm-secret
    2. Ensure you have a secret named terraform-demo-secret in AWS Secrets Manager with a JSON structure (e.g., {"username": "myappuser"}).
    3. Update terraform.tfvars with your AMI ID, instance type, and other variables as needed.
    4. terraform init
    5. terraform apply
    6. The EC2 instance will use the secret value (e.g., username) as the instance name.

010-rds-awssm​

  • Goal: Provision an AWS RDS MySQL instance with credentials managed in AWS Secrets Manager using Terraform modules.

  • Files:

    • main.tf
    • provider.tf
    • modules/secretmanager/main.tf, modules/secretmanager/variables.tf
    • modules/rds/main.tf, modules/rds/variables.tf

  • How to use:

    1. cd 010-rds-awssm
    2. Edit main.tf to set your desired username and password for the secret (or use variables).
    3. terraform init
    4. terraform apply
    5. After creation, connect to your RDS instance using the endpoint, username, and password stored in Secrets Manager.
    6. Example MySQL connection: 
      mysql -h <rds-endpoint> -P 3306 -u <username> -p
      (You can find <rds-endpoint> in the AWS RDS console or Terraform outputs.)

  • Notes:

    • Make sure your local MySQL client is compatible (MySQL 8.x recommended).
    • The RDS instance will use the credentials stored in AWS Secrets Manager, managed by the secretmanager module.
    • Security group and networking setup may be required to allow inbound connections from your IP.

011-rds-awssm-adv​

  • Goal: Provision an AWS RDS MySQL instance with credentials securely generated and stored in AWS Secrets Manager, and store all DB connection details (host, port, db name, username, password) in a separate secret for application use.

  • Files:

    • main.tf
    • modules/secretmanager/main.tf, modules/secretmanager/variables.tf
    • modules/rds/main.tf, modules/rds/variables.tf

  • How to use:

    1. cd 011-rds-awssm-adv
    2. Edit main.tf to set your desired username for the secret (password will be randomly generated).
    3. terraform init
    4. terraform apply
    5. After creation, you will have:
      • A secret in AWS Secrets Manager with the DB credentials (username & random password).
      • A separate secret in AWS Secrets Manager containing all connection info (endpoint, port, db name, username, password).
      • An RDS instance using these credentials.
    6. Example MySQL connection: 
      mysql -h <rds-endpoint> -P 3306 -u <username> -p
      (You can find <rds-endpoint>, username, and password in the connection info secret.)

  • Notes:

    • The password is generated only once and remains stable unless you taint or change the random password resource.
    • Do not overwrite the credentials secret with connection info; always use a separate secret for connection details.
    • Security group and networking setup may be required to allow inbound connections from your IP.

012-import-example​

  • Goal: Import an existing AWS EC2 instance (created manually) into Terraform management.

  • Files:

    • main.tf
    • imported-resources.tf (generated during import, then merged into main.tf)

  • How to use:

    1. Create the EC2 instance manually in the AWS Console.
    2. Create a main.tf with an import block: 
      import {
        id = "i-0e924e12540ecfa2f"
        to = aws_instance.imported_ec2_example
      }
    3. Initialize Terraform: 
      terraform init
    4. Generate the resource configuration from the existing instance: 
      terraform plan -generate-config-out=imported-resources.tf
    5. Move the generated resource configuration from imported-resources.tf into your main.tf.
    6. Import the resource into Terraform state: 
      terraform import aws_instance.imported_ec2_example i-0e924e12540ecfa2f
    7. Now, your manually created EC2 instance is managed by Terraform!

  • Notes:

    • After import, you can manage, update, or destroy the instance using Terraform as you would with any other resource.
    • Always review the generated configuration and adjust tags or settings as needed to match your infrastructure standards.

013-refresh-example​

  • Goal: Demonstrate how to use terraform apply -refresh-only to sync Terraform state with real infrastructure changes made outside of Terraform.

  • Files:

    • main.tf

  • How to use:

    1. cd 013-refresh-example
    2. Deploy an EC2 instance using terraform apply.
    3. Make a manual change to the EC2 instance in the AWS Console (e.g., add or modify a tag).
    4. Run: 
      terraform apply -refresh-only
      This updates the Terraform state file to reflect the real infrastructure.
    5. Run: 
      terraform plan
      Terraform will show any differences between your configuration and the actual state (e.g., tags present in state but not in main.tf).
    6. To bring your configuration in sync, manually update your main.tf file as needed and run terraform apply again.

  • Notes:

    • terraform apply -refresh-only only updates the state file; it does not change your infrastructure or configuration files.
    • Always review and manually update your configuration files to match desired state after using refresh-only.

Prerequisites​

  • Terraform installed
  • AWS account and credentials configured (aws configure or environment variables)
  • An existing AWS key pair for EC2 instances

Happy Terraforming!