root@xenial-verify-nameserver-not-considered-issue:~# cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# default I had
#auto eth0
#iface eth0 inet dhcp

# converted config to static
auto eth0
iface eth0 inet static
address 10.0.4.185
netmask 255.255.255.0
broadcast 10.0.4.255
gateway 10.0.4.1
network 10.0.4.0
# working - seen rendered into /etc/resolv.conf
#dns-nameserver 10.0.4.1
# trying two server, working as well
dns-nameservers 10.0.4.1 8.8.8.8
dns-search lxd
root@xenial-verify-nameserver-not-considered-issue:~# cat /etc/resolv.conf 
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 10.0.4.1
nameserver 8.8.8.8
search lxd