Dist-upgrading Ubuntu Server 18.04 located in remote site?

[Ralf Mardorf]

On Sun,  6 Feb 2022 21:44:43 -0500 (EST), Robert Heller wrote:
>> rmdir: failed to remove '/lib/modules/4.15.0-166-generic': Directory
>> not empty
>> 
>> Is the last message OK regarding non-empty directory?  
>
>
>The /lib is on the root file system, so it is not a problem at this
>point -- it does need to be looked into at some point.

Hi,

I suspect that /lib/modules/ contains modules that are not installed by
a package, but build with dkms. Running

  # dkms status

might provide this information. A leftover probably can be removed by
"dkms remove [...]", but sometimes checking

  # ls -l /lib/modules/* /var/lib/dkms/*

and manually deleting the leftover by "rm [...]" is required.
Unfortunately dkms can be configured to be in another path, but
/var/lib/dkms/.

Regards,
Ralf