Comment 26 for bug 1624320

I set up an Ubuntu 18.04 test server today as an LXD host machine and ran into this issue.

network:
  version: 2
  renderer: networkd
  ethernets:
    ens33:
      dhcp4: no
      dhcp6: no

  bridges:
    br0:
      interfaces: [ens33]
      dhcp4: no
      dhcp6: no
      addresses: [192.168.1.101/24]
      gateway4: 192.168.1.1
      nameservers:
        addresses: [192.168.1.1, 8.8.8.8, 8.8.4.4]

root@bionic:/home/bionic# systemd-resolve --status
Global
         DNS Servers: 192.168.1.1
          DNSSEC NTA: 10.in-addr.arpa
                      16.172.in-addr.arpa
                      168.192.in-addr.arpa
                      17.172.in-addr.arpa
                      18.172.in-addr.arpa
                      19.172.in-addr.arpa
                      20.172.in-addr.arpa
                      21.172.in-addr.arpa
                      22.172.in-addr.arpa
                      23.172.in-addr.arpa
                      24.172.in-addr.arpa
                      25.172.in-addr.arpa
                      26.172.in-addr.arpa
                      27.172.in-addr.arpa
                      28.172.in-addr.arpa
                      29.172.in-addr.arpa
                      30.172.in-addr.arpa
                      31.172.in-addr.arpa
                      corp
                      d.f.ip6.arpa
                      home
                      internal
                      intranet
                      lan
                      local
                      private
                      test

Link 6 (tun0)
      Current Scopes: LLMNR/IPv4 LLMNR/IPv6
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no

Link 5 (veth0OI7SQ)
      Current Scopes: LLMNR/IPv6
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no

Link 3 (br0)
      Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
 DNSSEC supported: no
         DNS Servers: 192.168.1.1
                      8.8.8.8
                      8.8.4.4

Link 2 (ens33)
      Current Scopes: none
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no

root@bionic:/home/bionic# ping google.com
ping: google.com: Temporary failure in name resolution

Also the error message is misleading, there's nothing "temporary" about this failure. It's permanent.

I can reach IP addresses directly but all DNS lookups are failing, preventing me from doing upgrades and normal operations.