we recently got rid of extra arg validation for preflight check:
9f21f5dd1e
the import-boss configuration will help us control exactly what
gets added/used in kubeadm. In this PR, we add a white-list of
the exact packages we use currently.
We will need to review these, make new PR(s) to eliminate things
we don't want to be depending on (just like the cloud provider related code).
00aeecd712