What is a Terraform data source, really?
Most explanations jump straight into syntax.
This lesson takes a different path.
In Terraform, a data source is not a shortcut, a helper, or a convenience feature.
It is a read-only observation node inside Terraform’s evaluation graph.
A data source does not create infrastructure.
It does not manage lifecycle.
And it does not express intent.
Instead, it answers a single question:
What is already true about the world right now?
That distinction matters.
Because Terraform draws a hard boundary between observation and decision.
Resources define desired change.
Data sources only provide context for the plan.
This lesson explains:
- Why data sources have no lifecycle
- How they participate in the dependency graph without controlling it
- Why external changes can affect plans without any code changes
- And why Terraform refuses to treat observation as ownership
No AWS service walkthroughs.
No step-by-step instructions.
Just how Terraform reasons.
👉 Watch the full lesson below to build a correct mental model before learning syntax.