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🛠️ Quick Guide: Infrastructure as Code (IaC)

Infrastructure as Code (IaC) is the practice of managing and provisioning infrastructure using machine-readable configuration files, rather than manual processes.

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✅ Benefits of IaC

• Consistency: Avoid configuration drift between environments.
• Speed: Provision infrastructure quickly and repeatedly.
• Version Control: Store and audit infrastructure changes via Git.
• Automation: Integrate with CI/CD pipelines for full automation.
• Scalability: Easily replicate infrastructure for different environments.

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🧰 Common IaC Tools

Tool	Language	Best For
Terraform	HCL	Cloud-agnostic, modular infrastructure
Pulumi	TypeScript, Python, Go, etc.	IaC with familiar programming languages
AWS CloudFormation	YAML/JSON	AWS-native infrastructure
Ansible	YAML	Configuration management & provisioning
Chef/Puppet	Ruby DSL	Configuration enforcement at scale

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🔧 Example: Terraform

provider "aws" {
  region = "us-east-1"
}

resource "aws_instance" "web" {
  ami           = "ami-0abcdef1234567890"
  instance_type = "t2.micro"
}

• Declare what infrastructure you want
• Plan the changes (terraform plan)
• Apply the changes (terraform apply)

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📦 Declarative vs Imperative

• Declarative: You define what the desired state is (e.g., Terraform, CloudFormation).
• Imperative: You define how to reach the desired state step-by-step (e.g., Bash scripts).

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🛡️ Best Practices

• Keep IaC files in version control
• Use remote backends for storing state securely (e.g., S3 for Terraform)
• Apply modularization (use reusable modules)
• Separate environments (dev/staging/prod) clearly
• Always run plan before apply
• Use secret managers (e.g., Vault, AWS Secrets Manager) instead of hardcoding credentials

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🔄 Integrate with CI/CD

• Run IaC in CI pipelines to validate syntax and enforce policies (e.g., terraform validate)
• Trigger deployments with pull requests or tagged commits
• Use terraform destroy with caution (and never on production automatically)

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📚 Related Concepts

• Immutable Infrastructure: Rebuild servers from scratch instead of changing them
• GitOps: Git is the source of truth for deployments
• Policy as Code: Enforce governance using tools like OPA (Open Policy Agent)

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Infrastructure as Code is a cornerstone of modern DevOps — enabling teams to move fast, stay consistent, and reduce errors.

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