Carvel ytt
YAML templating tool that works on YAML structure instead of text
..., externalize values to variables, extract repeated snippets to functions, and make whole sections conditional. Patch on top of any configuration using ytt overlays. Express precise structural edits and invariant declaratively. ytt execution environment is hermetic and side-effect free, with no access to filesystem, network, time, randomness, or the operating system interfaces. This guarantees that templates produce identical output with the same inputs.