Learning Resources

This module is docs-first. The primary authority on Terraform is the HashiCorp developer documentation -- not books, not blog posts, not videos. Local book chunks in library/raw/semester-09-cloud-devops/books/ cover Git and the Linux CLI and are peripheral here; we use them only when PR and review culture needs grounding.

Source Stack

Source	Role	How to use it in this module
HashiCorp Terraform Developer Docs	Primary	Default authority for every Terraform concept: language, CLI, backends, modules, providers, lifecycle
Terraform Best Practices (terraform-best-practices.com)	Secondary	Community-maintained conventions for modules, naming, environments, CI
Open Policy Agent docs	Primary (Cluster 5)	Rego language, testing, CI integration
HashiCorp Sentinel docs	Secondary (Cluster 5)	Sentinel policy language reference
tfsec (migrating to Trivy)	Secondary (Cluster 5)	Static scanner for Terraform; rules catalog
Ansible Documentation	Secondary (Cluster 5)	Config-management reference; modules and inventory
AWS CDK v2 Developer Guide	Secondary (Cluster 5)	CDK constructs, synth, deploy
Pulumi documentation	Secondary (Cluster 5)	Pulumi concepts, programming-model vs Terraform
Pro Git, The Linux Command Line, Git from the bottom up (local chunks)	Peripheral	PR-review mechanics only; useful for Cluster 4

Resource Map by Cluster

Cluster 1: The IaC Mindset

Need	Best external source	Why
What IaC is, why it exists	Terraform: What is Infrastructure as Code?	Vendor-neutral framing of the problem
Declarative vs imperative	Terraform Intro	Explicit contrast with scripts
State model	Terraform: State	Canonical explanation of state
State locking	Terraform: State and backends -- locking	Locking semantics
Idempotency and the apply loop	Terraform Intro + Resource lifecycle	Together: why the same apply is safe twice

Cluster 2: Terraform Core

Need	Best external source	Why
Providers	Terraform Language: Providers	Provider block, required_providers, versions
Resources	Terraform Language: Resources	Syntax, meta-arguments, lifecycle
Data sources	Terraform Language: Data sources	Read-only queries
Variables	Terraform Language: Input Variables	Types, validation, sensitivity
Local values	Terraform Language: Local Values	Purpose and pitfalls
Outputs	Terraform Language: Output Values	How modules expose state
Plan	Command: terraform plan	Plan symbols, saved plans
Apply	Command: terraform apply	Apply-from-plan

Cluster 3: Modularity and Reuse

Need	Best external source	Why
Writing a module	Tutorial: Create a Terraform module	End-to-end module creation
Module conventions	Terraform Best Practices: module structure	Opinionated community guidance
Workspaces	Terraform Language: Workspaces	Purpose and limits of CLI workspaces
Backend block	Terraform Language: Backends	Backend configuration
Remote state	Terraform Language: Remote State	Cross-team state access
Environments	Terraform Best Practices: environment separation	Dir-per-env and repo-per-env patterns

Cluster 4: Managing Change

Need	Best external source	Why
Plan review discipline	Command: terraform plan + Best Practices: PR flow	Plan as the unit of review
moved blocks	Terraform Language: Refactoring with moved	Canonical docs
import blocks	Terraform Language: Importing infrastructure	Modern import block workflow
terraform state CLI	Command: terraform state	Last-resort state surgery
Lifecycle meta-arguments	Terraform Language: lifecycle	prevent_destroy, create_before_destroy, ignore_changes
PR review mechanics	Pro Git: Distributed Workflows (local chunks)	Git-side of the review loop

Cluster 5: IaC Beyond Terraform

Need	Best external source	Why
Ansible	Ansible: Getting started	Inventory, playbooks, idempotency
CDK	AWS CDK v2: Developer Guide	Constructs, App/Stack model
Pulumi	Pulumi: Concepts	Programming-model IaC
OPA / Rego	OPA: Documentation	Policy engine home
Sentinel	Sentinel: Documentation	HCP Terraform policy engine
tfsec / Trivy	tfsec docs (migrating to Trivy)	Static Terraform scanning

Concept-to-Source Map (Primary Concepts)

Primary concept	Best external source	Why this source
Declarative vs imperative	Terraform Intro	Vendor-neutral contrast
State and its hazards	Terraform: State	Authoritative on the model
Idempotency and convergence	Terraform Intro + Resource lifecycle	Model + mechanism
Providers / resources / data sources	Terraform Language: Providers	Authoritative
Variables / outputs / locals	Input Variables	Primary reference
Plan / apply / drift	Command: terraform plan	Authoritative on lifecycle commands
Reusable modules	Tutorial: Create a module	End-to-end worked example
Workspaces, envs, monorepo/polyrepo	Workspaces + Best Practices	Official + community
Remote state and locking	Backends	Authoritative
Plan review as PR culture	terraform plan	Saved-plan semantics
Refactoring: moved, import, state	Refactoring with moved + Importing infrastructure	The two canonical docs
Blast radius and safe defaults	lifecycle meta-arguments	Authoritative
Policy as code	OPA docs + Sentinel docs	Two canonical policy engines

External Resources (Validated)

All URLs below were checked against official or canonical sources during curriculum curation. Use them in preference to third-party blog posts unless you are already fluent and want a second exposition.

• Terraform Intro
• Terraform Language home
• Terraform Tutorials
• Terraform State
• Terraform State Locking
• Terraform Backends
• Terraform Remote State
• Terraform Workspaces
• Terraform Providers
• Terraform Resources
• Terraform Data Sources
• Terraform Input Variables
• Terraform Local Values
• Terraform Output Values
• Terraform lifecycle
• Terraform Command plan
• Terraform Command apply
• Terraform Command state
• Terraform Import (language)
• Terraform Refactoring with moved
• Terraform Tutorial: Create a module
• Terraform Best Practices
• Open Policy Agent docs
• HashiCorp Sentinel docs
• tfsec (migrating to Trivy)
• Ansible: Getting started
• AWS CDK v2: Developer Guide
• Pulumi: Concepts

Use Rules -- Docs-First Discipline

• Go to developer.hashicorp.com/terraform/language first, for every Terraform language question. The docs are the source of truth; blog posts are often out of date, especially since Terraform 1.1's addition of moved and 1.5's import block.
• When stuck on a provider's resource attributes, go to the provider's page in the Terraform Registry. Do not trust examples from blog posts written before 2023.
• For backends and state: read the backend-specific page (S3, GCS, HCP Terraform) before you configure one. Subtle differences (server-side encryption, KMS keys, IAM) live only in those pages.
• For refactors, read the moved and import pages before the PR. Every month saved guessing is a PR that does not destroy production.
• For policy, read the OPA tutorial and write your first policy the same day. Policy skills are muscle; they do not accumulate from reading alone.
• Book chunks (Pro Git, Linux Command Line, Git from the bottom up) are here for Cluster 4's PR-review context and for general shell fluency. They are not IaC sources -- do not escalate to them for Terraform questions.