[Bug 1588915] [NEW] networking.service does not wait for interfaces to be up

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Description:    Ubuntu 16.04 LTS (server)
Release:        16.04

systemd:
  Installed: 229-4ubuntu6
  Candidate: 229-4ubuntu6
  Version table:
 *** 229-4ubuntu6 500
        500 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     229-4ubuntu4 500
        500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 Packages

This issue is more about systemd integration then an issue with systemd
package itself.  The general problem is the distinction between the
network being configured and the network being up and what that means
for services that depend on the network.

upstream systemd has network.target (network is configured) and network-
online.target (network is up), however xenial server (dunno about
desktop) doesn't seem to use network-online.target.  The result of which
is, as soon as the network is configured both network.target and
network-online.target are considered complete.  At which point services
dependent on either of those will get started.  However this can lead to
problems if the services in question are actually dependent on the
network (ie dns lookups) when they are starting up.

Here's an example of what I mean.  If you install openntpd and add the
-s option there is a race on boot if it will or wont be able to do the
initial sync.

Jun 02 16:58:02 xenial64 systemd[1]: Reached target Network.
Jun 02 16:58:02 xenial64 systemd[1]: Starting OpenNTPd Network Time Protocol...
Jun 02 16:58:02 xenial64 systemd[1]: Reached target Network is Online.
Jun 02 16:58:02 xenial64 ntpd[920]: constraint certificate verification turned off
Jun 02 16:58:02 xenial64 ntpd[928]: ntp engine ready
Jun 02 16:58:02 xenial64 kernel: tg3 0000:02:00.0 enp2s0: Link is down
Jun 02 16:58:05 xenial64 kernel: tg3 0000:02:00.0 enp2s0: Link is up at 1000 Mbps, full duplex
Jun 02 16:58:05 xenial64 kernel: tg3 0000:02:00.0 enp2s0: Flow control is on for TX and on for RX
Jun 02 16:58:05 xenial64 kernel: IPv6: ADDRCONF(NETDEV_CHANGE): enp2s0: link becomes ready
Jun 02 16:58:17 xenial64 ntpd[920]: no reply received in time, skipping initial time setting

openntpd was started 3 seconds before the interface even got link.

I believe this issue is only going to effect physical servers with
static ips.  vm's interfaces will instantly have link when they are
brought up and dhcp, the interface will already be up or else they
wouldn't have been able to get an ip.

thanks
jim

** Affects: ifupdown (Ubuntu)
     Importance: Undecided
         Status: Incomplete


** Tags: systemd-boot
-- 
networking.service does not wait for interfaces to be up
https://bugs.launchpad.net/bugs/1588915
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