Kustomize is a tool to manage and customize Kubernetes manifest files. It allows you to select and patch your base Kubernetes resources before applying them to different environments and is now natively supported by kubectl. We like it because it helps keep your code DRY and in contrast to Helm (which is trying to do many things — package management, version management and so on), we find Kustomize follows the Unix philosophy: do one thing well and expect the output of every program to be input to another.