root@armadillo:~# ping google.com
ping: google.com: Temporary failure in name resolution
root@armadillo:~# systemctl status systemd-networkd-wait-online.service
�� systemd-networkd-wait-online.service - Wait for Network to be Configured
   Loaded: loaded (/lib/systemd/system/systemd-networkd-wait-online.service; ena
   Active: failed (Result: exit-code) since Fri 2019-04-19 18:10:22 JST; 1min 32
     Docs: man:systemd-networkd-wait-online.service(8)
  Process: 466 ExecStart=/lib/systemd/systemd-networkd-wait-online (code=exited,
 Main PID: 466 (code=exited, status=1/FAILURE)

Apr 19 18:09:19 armadillo systemd-networkd-wait-online[466]: ignoring: lo
Apr 19 18:09:19 armadillo systemd-networkd-wait-online[466]: ignoring: lo
Apr 19 18:09:21 armadillo systemd-networkd-wait-online[466]: ignoring: lo
Apr 19 18:09:21 armadillo systemd-networkd-wait-online[466]: ignoring: lo
Apr 19 18:09:33 armadillo systemd-networkd-wait-online[466]: ignoring: lo
Apr 19 18:10:16 armadillo systemd-networkd-wait-online[466]: ignoring: lo
Apr 19 18:10:22 armadillo systemd[1]: systemd-networkd-wait-online.service: Main
Apr 19 18:10:22 armadillo systemd[1]: Failed to start Wait for Network to be Con
Apr 19 18:10:22 armadillo systemd[1]: systemd-networkd-wait-online.service: Unit
Apr 19 18:10:22 armadillo systemd[1]: systemd-networkd-wait-online.service: Fail