Dockerized Image build service (with Kaniko?)

[oleg-nenashev]

To simplify building Jenkins images in Docker, it would be great to be able to package and deploy images from the container itself. It is possible to use Kaniko or PodMan/Buildah for such purpose.

Acceptance criteria:

• Update the Custom WAR Packager image to be based on Kaniko (or create a new image)
• Update Docker build steps to support the Kaniko invocation from inside the container
• Expose publishing option so that the created images can be deployed to DockerHub or private container images
• Document the flow and create a demo for it

For evaluation purposes, https://github.com/jenkinsci/ci.jenkins.io-runner can be built with Kaniko out of the box

[usernameisnull]

Has this function been implemented?