Deployment, Build, and Release Management
Deployment questions test the build-deploy pipeline and static content. Know the phases: setup:di:compile (generates factories, proxies, interceptors), setup:static-content:deploy (per theme and locale), and setup:upgrade (schema and data patches). In production, di:compile and static deploy happen at build time, not on the production node. Know app/etc/config.php and env.php roles: config.php holds module enablement and is committed; env.php holds environment-specific credentials and is not committed.
Traps: running di:compile in production mode on a live node, forgetting --area or locale flags for static deploy, and confusing setup:upgrade with setup:db-data:upgrade. Also know maintenance mode, the app:config:dump and app:config:import commands for config management, and that data patches are versioned and run once. Cloud has its own build and deploy hooks in .magento.app.yaml and .magento.env.yaml.
Worked example
Requirement: "Deploy a new module to production with zero downtime concerns." Build phase: run setup:di:compile and setup:static-content:deploy with the production locales, then deploy the artifact. Deploy phase: enable maintenance mode, run setup:upgrade, flush caches, disable maintenance mode. Config changes go through app:config:dump locally and app:config:import on the target so environment-specific values stay in env.php.
Rule of thumb: compile and static-deploy at build, schema and config at deploy.