systemd-resolve/NetworkManager changes (17.10 -> 18.04)

[Teresa e Junior]

Em 19/05/2018 15:59, Teresa e Junior escreveu:
> Whenever I connect my laptop to a new network with NetworkManager, I 
> don't need to manually set the DNS servers if I configure 
> systemd-resolve with the following (in 
> /etc/systemd/network/wireless.network):
> 
> [Match]
> Name=wl*
> 
> [DHCP]
> UseDNS=false
> 
> [Network]
> DNS=8.8.4.4 208.67.220.220
> 
> The problem is that this stopped working when I upgraded from Artful to 
> Bionic:
> 
> $ systemd-resolve --status | awk '/DNS Servers/,/^$/'
>           DNS Servers: 189.4.0.242
>                        189.4.0.153
>                        189.4.0.234
> 
> But it works if I manually restart systemd-networkd and network-manager:
> 
> $ sudo systemctl restart systemd-networkd.service
> $ sudo systemctl restart network-manager.service
> $ systemd-resolve --status | awk '/DNS Servers/,/^$/'
>           DNS Servers: 8.8.4.4
>                        208.67.220.220
> 
>           DNS Servers: 8.8.4.4
>                        208.67.220.220
> 
> How can I restore the old behaviour, or what is the preferred method now?

The reason why restarting the services worked is that systemd-networkd 
hadn't been started in the first place. Enabling systemd-networkd solved 
the problem.

My main concern now is who disabled systemd-networkd in the last upgrade 
and why. It is strange too that the serviced status returned "disabled; 
vendor preset: enabled".

$ grep resolve /lib/systemd/system-preset/90-systemd.preset
enable systemd-resolved.service

I thought some postinst script disabled the service (I'm sure I didn't), 
but that doesn't seem to be the case:

$ ack --shell systemd-resolved /var/lib/dpkg/info/
/var/lib/dpkg/info/systemd.postinst
44:    systemctl enable systemd-resolved.service || true
154:    _systemctl try-restart systemd-resolved.service || true

/var/lib/dpkg/info/libnss-resolve:amd64.postinst
41:    systemctl enable systemd-resolved.service
43:        deb-systemd-invoke start systemd-resolved.service || true