Kustomize is a project-level configuration manager. This tool allows you to modify the default configuration of your microservices on a per-environment basis in a simple declarative way with pure YAML. It is based on overlays that are patches for the configuration files generated by the console and are applied at deployment time.
To learn more about how to use Kustomize with your projects take a look at the following pages:
For hands-on examples, take a look at the use cases page.