Docker Jobs and Services

Part of the GitLab CI course

A pipeline runner is a bare machine, and by default it has no idea your project needs Python 3.12, or a specific version of Node, or any particular tool at all. Left alone, it hands your job whatever plain, generic environment it happens to keep around, which is rarely what a real test suite needs.

Think of the default runner environment as a bare workbench: it has surfaces to work on, but none of your actual tools are laid out on it. The image: keyword is how you tell GitLab "before running this job's script, hand me a fully equipped workbench instead, one that already has Python installed, or Node, or whatever this job needs." ...