YAML Pipeline Hierarchical Structure

YAML Pipelines in Azure DevOps are the foundation for automating continuous integration (CI) and continuous delivery (CD) workflows. A pipeline is defined in a YAML file and controls the entire process of building, testing, and deploying an application. The pipeline is built from three main layers. Steps are the smallest units of work and can be either scripts or tasks. Jobs are collections of steps that run in sequence on a single agent. Stages represent high-level phases of the pipeline, such as "Build" or "Deploy to Production," and each stage can contain multiple jobs. Variables and templates are the tools that make pipelines modular and reusable. Variables hold values that change between environments, like a connection string or a target URL, while templates let you define common logic once and reuse it across many pipelines.