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Infrastructure

Infrastructure as Code Patterns

Question

What are the key principles and patterns of Infrastructure as Code? How do you structure IaC for multiple environments?

Answer

Key IaC principles: declarative over imperative, idempotent operations, version control everything, and immutable infrastructure. For multiple environments, use modules for reusable components, separate state files per environment, use workspaces or directory structures (dev/staging/prod), parameterize with variables and tfvars files, and implement DRY (Don't Repeat Yourself) through modules. Always test changes in lower environments first.

Why This Matters

IaC is the foundation of modern DevOps practices. Well-structured IaC enables reproducible infrastructure, reduces configuration drift, facilitates disaster recovery, and allows infrastructure changes to go through the same code review process as application code.

Code Examples

Terraform module structure

hcl
Common Mistakes
  • Hardcoding environment-specific values
  • Not using remote state with locking
  • Creating overly complex module hierarchies
Follow-up Questions
Interviewers often ask these as follow-up questions
  • How do you handle secrets in Infrastructure as Code?
  • What is the difference between Terraform workspaces and directory-based separation?
  • How do you test infrastructure code before applying?
Tags
iac
terraform
infrastructure
patterns
best-practices