do-release-upgrade is crashing when going from 16.04 to 18.04

[Paul Smith]

On Sat, 2019-04-27 at 13:23 -0400, Robert Heller wrote:
> > For quite a while now Ubuntu has used first dnsmasq, and then systemd-
> > resolve, and so nscd has been obsolete.
> 
> Ok, then I need to get rid of systemd-resolve or else disable it.  I have/will 
> have some other 16.04 systems to update, and I know that nscd on 14.04 has 
> always been a pain.  I think the problem is that nscd is not always 
> respecting the LAN-provided DNS server and is wanting to use 8.8.8.8 and 
> 4.4.4.4, which is fine when there is "nothing" on the LAN (no intranet 
> services)...  I don't know if systemd-resolve is any better.  I really want 
> these machines to use the DNS server provided by the DHCP server and not try 
> to play "games" with some kind of machine-local caching DNS server.  The LAN 
> server is *already* caching DNS for the LAN, as well as providing DNS for the 
> mahines on the LAN, including LAN-provided services.

That's fine, but note that a large amount of modern software such as
Docker, Kubernetes, qemu/etc., VPN networking, etc. all require these
tools to be installed in order to work properly.  Any type of
virtualization or container needs to have a virtualized network and
this requires games to be played with DNS, a local DHCP server running,
etc.  VPNs need to be able to perform split DNS (typically).  Even some
wireless/roaming setups that want to be able to access both local and
global facilities use them.

If you don't need anything more than a basic wired network interface
with simple DHCP, running without any virtualized networking or
multiple DNS lookup realms, you can remove these other facilities and
reconfigure NetworkManager to manage /etc/resolv.conf directly.