The "generate-csr" command is useful in cases users don't
wish to use the default certificate duration that kubeadm has
hardcoded to 1 year. The command can also be used when the
certificate rotation process is done manually, out of bounds
with an external CA.
The command resided under "kubeadm alpha certs".
It will be promoted to GA in 1.20 as "kubeadm certs".
The existing command "kubeadm alpha" will
remain present for one more release, but it will be hidden
from documentation as it is deprecated.
Qiming Teng
Tim Bannister
Lubomir I. Ivanov