[Bug 2003250] Re: networkctl reload with bond devices causes slaves to go DOWN and UP, causing couple of seconds of network loss

[Junien Fridrick]

I agree that the importance should be higher than "Low".

This bug is also triggered every time a "netplan apply" is run, since
netplan will always re-generate the systemd-networkd config files.

VLAN interfaces are also torn down and recreated.

This is highly problematic on critical networking hosts, such as
firewalls, since any networking configuration change will trigger
seconds of downtime, which can lead to VRRP failovers, etc...

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Title:
  networkctl reload with bond devices causes slaves to go DOWN and UP,
  causing couple of seconds of network loss

Status in systemd package in Ubuntu:
  Triaged
Status in systemd source package in Jammy:
  Triaged
Status in systemd source package in Kinetic:
  Triaged

Bug description:
  We currently use Ubuntu 22.04.1 LTS including updates for our production cloud (switched from legacy Centos 7).
  Although we like the distribution we recently hit serious systemd buggy behavior described in [1] bugreport using packages [2].

  Unfortunatelly the clouds we are running consist of openstack on top
  of kubernetes and we need to have complex network configuration
  including linux bond devices.

  Our observation is that every time we apply our configuration via
  CI/CD infrastructure using ansible and netplan (regardless whether
  there is actual network configuration change) we see approximatelly
  8-16 seconds network interruptions and see bond interfaces going DOWN
  and then UP.

  We expect bond interfaces stay UP when there is no network
  configuration change.

  We went though couple of options how to solve the issue and the first
  one is to add such existing patch [3] into current
  systemd-249.11-0ubuntu3.6.

  Could you comment whether this kind of non-security patch is likely to land in 22.04.1 LTS soon.
  We are able to help to bring patch into systemd package community way if you suggest the steps.

  
  [1] https://github.com/systemd/systemd/issues/25067
  [2] Packages
  root at controlplane-001:/etc/apt0# apt list | grep -E '^(systemd/|netplan.io)'
  netplan.io/jammy-updates,now 0.105-0ubuntu2~22.04.1 amd64 [installed,automatic]
  systemd/jammy-updates,now 249.11-0ubuntu3.6 amd64 [installed,automatic]
  [3] https://github.com/systemd/systemd/pull/25162
  [4] # lsb_release -rd
  Description:    Ubuntu 22.04.1 LTS
  Release:        22.04

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