In the Alpha stage of the feature in kubeadm to support
a rootless control plane, the allocation and assignment of
UID/GIDs to containers in the static pods will be automated.
This automation will require management of users and groups
in /etc/passwd and /etc/group.
The tools on Linux for user/group management are inconsistent
and non-standardized. It also requires us to include a number of
more dependencies in the DEB/RPMs, while complicating the UX for
non-package manager users.
The format of /etc/passwd and /etc/group is standardized.
Add code for managing (adding and deleting) a set of managed
users and groups in these files.
