Terraform authentication failures often feel random.
Nothing in your code changed.
The plan ran yesterday.
Today, it fails. Or worse, it succeeds in the wrong account.
This is not a Terraform bug.
And it is not bad luck.
It is authentication precedence.
Terraform does not choose the “correct” identity.
It follows a strict, silent order to decide which identity a provider will use.
The first valid identity it finds wins, even if that identity was never your intent.
That is why:
- Terraform can succeed in the wrong account
- Environment variables silently override configuration
- Old shell sessions break “working” code
- Hard-coded credentials cause failures long after they are forgotten
Most engineers debug permissions first.
That is usually the wrong move.
The real question is not “What is Terraform allowed to do?”
It is “Where did this identity come from?”
In this video, I walk through:
- How authentication precedence actually works
- Why providers resolve identity independently
- The most common real-world failure patterns
- Why some of the most dangerous mistakes never produce errors at all
This lesson focuses on mental models, not commands.
Once the model is clear, the failures stop feeling mysterious.