YAML
ExplainedProtocol / format
Also known as: YAML Ain’t Markup Language
Readable, indentation-based configuration format used for CI/CD pipelines and Kubernetes manifests.
YAML, explained
Written by EduVerseWhat it is
YAML is a text format for configuration and data that uses indentation instead of brackets. Keys and values are written as name: value, and list items start with a hyphen. It describes the same kinds of structures as JSON, but is meant to be easier for people to read and edit.
Why teams use it
Configuration files get read and edited by people all the time, so readability matters. YAML allows comments and needs very little punctuation, which is why Docker Compose, Kubernetes and GitHub Actions use it. The downside: whitespace has meaning, so one wrong indent can quietly change what your file says.
An example from work
Your GitHub Actions workflow in .github/workflows/ci.yml fails before a single step runs, with an error saying the workflow file is invalid. You indented a run line two spaces too few, or used a tab, which YAML doesn’t allow for indentation. Fixing the alignment gets the pipeline going.
Our own explanation, not a quote from the book.
In the book
Sentences from The Software Realm, Decoded that mention YAML, exactly as printed.
1 more passages about YAML in the full book
Read every conversation where YAML comes up, with the interactive slides and demos.
Where it fits
Configuration (Docker Compose, Kubernetes, GitHub Actions)
Coverage in the book
Explained and compared with alternatives, so you know where and why it’s used.
