We needed to modify deployments in the background and decided against Kyverno (too big, too complex).

Instead a leightweight mutating Webhook called "kTailor" was built and published under Apache 2.0. Its main purpose is to insert env vars, initContainers and sidecars.

For more details see https://dev.to/docdiesel/how-i-added-initcontainers-and-env-... or https://www.ktailor.dev/ .

Try at killercoda: https://killercoda.com/ktailor-demo