* Review variables available in bare-metal kubernetes modules
for Container Linux and Fedora CoreOS
* Deprecate cluster_domain_suffix variable
* Remove deprecated container_linux_oem variable
* Choose the Container Linux derivative Flatcar Linux on
bare-metal by setting os_channel to flatcar-stable, flatcar-beta
or flatcar-alpha
* As with Container Linux from Red Hat, the version (os_version)
must correspond to the channel being used
* Thank you to @dongsupark from Kinvolk