Chapter 6. Custom Builder

Custom build is designed to fill the gap that was created when everybody jumped into creating Docker images. Still there is a requirement to produce individual artifacts (packages, jars, wars, installable zips, base images etc.) This is where Custom build is the perfect match to fill in that gap. Additionally Custom build allows implementing any extended build process for example, CI/CD flow that runs unit or integration tests. The limit here is just the imagination of the custom builder image author.

To fully utilize the power of Custom build one needs to be understand how to create a builder image that will be capable of building desired objects.

The builder image upon invocation receives following environment variables with the information needed to proceed with the build:

Although the custom builder image author has a great flexibility in defining the build process on its own, still they should follow a few required steps necessary to seamlessly run a build inside of OpenShift Enterprise. The required steps for a custom builder image are following: