[Bug 1798107] [NEW] netplan render does not set DNS nameservers correctly

[pseudonomous]

Public bug reported:

I've got a netplan file:

# cat /etc/netplan/00-static-ip.yaml
# Let systemd-netword manage all devices on this system
network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s0:
      dhcp4: no
      dhcp6: no
  bridges:
    br0:
      dhcp4: no
      dhcp6: no
      interfaces:
        - enp3s0
      addresses:
        - 192.168.1.122/24
      gateway4: 192.168.1.1
      nameservers:
        addresses:
          - 192.168.1.1

I can do a:

netplan generate
netplan apply

but this does not result in a configuration where my queries will be
resolved by my nameserver, which happens to be mikrotik router.
Instead, queries appear to be answered by the systemd-resolved on
localhost and it's unclear to me what nameserver that is using to
resolve queries, but I'm certain that it is not 192.168.1.1 because:

host mikrotik 192.168.1.1

will return:

Using domain server:
Name: 192.168.1.1
Address: 192.168.1.1#53
Aliases: 

mikrotik has address 192.168.1.1


while 

host mikrotik

will return

Host mikrotik not found: 2(SERVFAIL)

While I'm not 100% sure the root cause of this bug lies in the netplan
code-base vs. either systemd-resolved or one of the myriad other tools
which have complicated DNS resolution in recent years but, in practical
terms, the result is that netplan does not work like the documentation
suggests it should.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: netplan.io 0.36.3
ProcVersionSignature: Ubuntu 4.15.0-36.39-lowlatency 4.15.18
Uname: Linux 4.15.0-36-lowlatency x86_64
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Tue Oct 16 09:17:58 2018
InstallationDate: Installed on 2018-10-16 (0 days ago)
InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: netplan.io
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: netplan.io (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug bionic

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https://bugs.launchpad.net/bugs/1798107

Title:
  netplan render does not set DNS nameservers correctly

Status in netplan.io package in Ubuntu:
  New

Bug description:
  I've got a netplan file:

  # cat /etc/netplan/00-static-ip.yaml
  # Let systemd-netword manage all devices on this system
  network:
    version: 2
    renderer: networkd
    ethernets:
      enp3s0:
        dhcp4: no
        dhcp6: no
    bridges:
      br0:
        dhcp4: no
        dhcp6: no
        interfaces:
          - enp3s0
        addresses:
          - 192.168.1.122/24
        gateway4: 192.168.1.1
        nameservers:
          addresses:
            - 192.168.1.1

  I can do a:

  netplan generate
  netplan apply

  but this does not result in a configuration where my queries will be
  resolved by my nameserver, which happens to be mikrotik router.
  Instead, queries appear to be answered by the systemd-resolved on
  localhost and it's unclear to me what nameserver that is using to
  resolve queries, but I'm certain that it is not 192.168.1.1 because:

  host mikrotik 192.168.1.1

  will return:

  Using domain server:
  Name: 192.168.1.1
  Address: 192.168.1.1#53
  Aliases: 

  mikrotik has address 192.168.1.1

  
  while 

  host mikrotik

  will return

  Host mikrotik not found: 2(SERVFAIL)

  While I'm not 100% sure the root cause of this bug lies in the netplan
  code-base vs. either systemd-resolved or one of the myriad other tools
  which have complicated DNS resolution in recent years but, in
  practical terms, the result is that netplan does not work like the
  documentation suggests it should.

  ProblemType: Bug
  DistroRelease: Ubuntu 18.04
  Package: netplan.io 0.36.3
  ProcVersionSignature: Ubuntu 4.15.0-36.39-lowlatency 4.15.18
  Uname: Linux 4.15.0-36-lowlatency x86_64
  ApportVersion: 2.20.9-0ubuntu7.4
  Architecture: amd64
  CurrentDesktop: ubuntu:GNOME
  Date: Tue Oct 16 09:17:58 2018
  InstallationDate: Installed on 2018-10-16 (0 days ago)
  InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
  ProcEnviron:
   TERM=xterm-256color
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: netplan.io
  UpgradeStatus: No upgrade log present (probably fresh install)

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