HashiCorp Terraform 003 Resources and Data Sources Guide

Study HashiCorp Terraform 003 Resources and Data Sources: key concepts, common traps, and exam decision cues.

This lesson matters because Terraform configuration questions often ask whether Terraform is creating something, reading something, or wiring values together. Resources, data sources, and expressions answer different parts of that story.

Config chooser

If the scenario is mostly about… Strongest first fit
managing an object Terraform owns resource
reading information Terraform does not own here data source
computing or transforming values in configuration expression

Decision order that usually wins

  1. Ask whether Terraform is creating, reading, or wiring values.
  2. If Terraform should manage the object, use a resource.
  3. If Terraform should only look up existing information, use a data source.
  4. If the question is about combining or transforming values, stay in expressions.
  5. Do not assume every referenced thing must be created here.

Common traps

Trap Better rule
treating data sources like managed resources data sources read; resources manage
treating expressions like separate infrastructure expressions wire values and logic together
assuming every object Terraform references must be created here some information is only read

Quiz

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Revised on Sunday, May 10, 2026