Container engine should accept valid subnet for container address range
When provisioning container engine, entering any valid subnet into the container address range causes the build to immediately fail on a regex failure. It appears that the decorative /14 UI element never makes it into the data and cluster.cluster_ipv4_cidr, failing to include the /14.
Further, the cli command suggested by the UI appears to not accept the --container_ipv4_cidr parameter in any form, with our without the /14 and seems the --container_ipv4_cidr argument itself is invalid.
The 10/8 subnet collides with the far side of a VPN connection and, as we'd already adopted (fortunately) the upper bounds of the 172 range to prevent collisions like this, it would be great to not have to NAT the entire 10/8 subnet just for container engine.