Due to the specific nature of this section, we won't be using MiniShift, so let's stop it for now:
$ minishift stop
...
Then, start the Vagrant VMs instead:
$ vagrant up
...
<output omitted>
...
Finally, open a session in the openshift VM:
$ vagrant ssh openshift
$ sudo -i
An Admission Controller is a subroutine that's invoked after a request to the API is authenticated and authorized, but before it's persisted to etcd. Admission Controller serve the purpose of mutating and validating resources to be persisted, such as adding various annotations and defaults and making sure that they conform to specific restrictions. All admission controllers are chained, so that mutating controllers are applied first and then validating ones.
The following diagram illustrates the overall resource admission process:
OpenShift resource admission chain...
