We've long had root logins disabled on clearlinux, but we've
inadvertently left SSHD to allow root login with certificates/keys for a
while. This will be disabled in the future as well and all root logins,
certificate or password based authentication or not, will be refused by
default in ClearLinux by sshd.
If you are using SSH keys to log in as root to ClearLinux machines, I
suggest you stop doing so and instead rely on unprivileged accounts (and
use sudo), even if you are using keys. If you had installed and used
keys yourself, you may lose that access in future updates.
For most ClearLinux systems, the change has no impact, since ClearLinux
does not ship keys nor do I suspect anyone is using keys to log in as
root. If you are however using this feature for automation, you can use
an sshd_config option (`PermitRootLogin prohibit-password`) to allow
this in again.