Lecture on Terraform

Introduction

• Overview of Terraform and its usage
• Comparison with Ansible
• Terraform architecture
• Example configuration file

What is Terraform?

• Tool for automating and managing infrastructure
• Open source, declarative language
• Specifies desired end result rather than step-by-step execution
• Used for infrastructure provisioning

Infrastructure Provisioning

• Setting up infrastructure from scratch for applications
• Example: Using AWS to deploy microservices and database containers

Steps in Infrastructure Setup

1. Provisioning infrastructure
   • Create private network space
   • Deploy servers and install Docker
   • Set up security (firewalls, etc.)
2. Deploying applications
   • Deploy Docker containers on prepared infrastructure

Role of Terraform

• Used mainly for initial provisioning
• Handles tasks like creating VPC, spinning up servers, setting up security, etc.
• Ensures order of tasks is correct (dependencies)

Terraform vs. Ansible

• Terraform: Mainly for infrastructure provisioning, newer, advanced in orchestration
• Ansible: Mainly for configuration, more mature, used for deploying applications, installing software, etc.
• Common practice to use both for their strengths

Managing Infrastructure with Terraform

• Adding/removing resources
• Reconfiguring existing infrastructure
• Automating repetitive tasks
• Replicating environments (e.g., development, production, staging)

Terraform Architecture

• Core Components
  • Terraform Core: Uses configuration files and state
  • Providers: Specific to technologies (AWS, Kubernetes, etc.)
• Configuration File
  • Declarative, defines desired state
  • Example: AWS provider, creating VPC, Kubernetes provider creating namespace

Declarative vs. Imperative

• Declarative: Define end state, Terraform figures out execution steps
• Imperative: Define exact steps to execute
• Easier updates and management with declarative style

Terraform Commands

• Refresh: Queries infrastructure provider for current state
• Plan: Constructs a plan based on configuration file and current state
• Apply: Executes the plan to reach desired state
• Destroy: Removes all created resources

Summary

• Terraform simplifies infrastructure provisioning
• Useful for creating, managing, and replicating environments
• Works best for infrastructure setup; combine with tools like Ansible for full lifecycle management

Conclusion

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