If you follow the installation instructions for Red Hat's Container Development Kit 3.5, on RHEL 7.5, most everything works well, until you get to the point of starting the virtualized minishift host:
You get a failure when trying to connect to Docker on the VM. The problem is that, if you strictly follow the instructions, your user is not a member of the 'libvirt' group. This is easy to rectify, though. All you need to do is:
1) Remove the existing minishift VM:
2) Add yourself to the requisite group:
3) And relaunch minishift:
Hopefully I can get the docs updated, so this isn't necessary, in the near future.