The central idea is describing the desired end state and letting a tool work out how to get there from wherever you currently are. That convergence property is what makes the approach reliable.
Scripts describe steps, definitions describe outcomes
A provisioning script assumes a starting point and breaks when reality differs. A declarative definition compares desired state against actual state and produces only the difference, so it works from any starting point and is safe to run repeatedly.
Idempotence is the property you are buying
Running the same definition ten times produces the same result as running it once. This is what lets infrastructure changes be reviewed, retried and automated without a human deciding each time whether it is safe to run again.
The definition becomes the documentation
Because the code is the source of truth for what exists, the perennially stale architecture document stops mattering. This only holds if nobody changes infrastructure by hand, which is the discipline the whole approach depends on.
Action step
Pick one environment and identify every resource in it that is not defined in code. That gap is your real starting point.
Tech Skills Library is independent and is not affiliated with, accredited by, or endorsed by HashiCorp, any cloud provider, or any tooling vendor named in this course. Tool behaviour, licensing and provider APIs change frequently; always confirm current details in the official documentation for the version you are running. This course teaches engineering practice and does not issue a certification or credential.