[Bug 1999285] Re: systemd-networkd constantly resets link on i350 when attempting to apply dhcp server provided MTU

Fri Feb 24 20:55:34 UTC 2023

I'm not sure it makes sense to SRU this to Jammy.

Firstly, there is an easy work around for this (see e.g.
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1881207/comments/5
for a way to avoid changing the DHCP server itself), and this bug does
not seem to affect a large number of users. Second, the PR that fixes
this upstream is fairly large for an SRU. We actually would need
https://github.com/systemd/systemd/pull/21344, and the commit you linked
is a follow-on to this. Finally, one of the patches does not apply
cleanly to Jammy.

If it's an option for your setup, this bug should not be present in
Kinetic.

** Also affects: systemd (Ubuntu Focal)
   Importance: Undecided
       Status: New

** Also affects: systemd (Ubuntu Jammy)
   Importance: Undecided
       Status: New

** No longer affects: systemd (Ubuntu Focal)

** Changed in: systemd (Ubuntu)
       Status: New => Fix Released

** Changed in: systemd (Ubuntu Jammy)
       Status: New => Won't Fix

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https://bugs.launchpad.net/bugs/1999285

Title:
  systemd-networkd constantly resets link on i350 when attempting to
  apply dhcp server provided MTU

Status in systemd package in Ubuntu:
  Fix Released
Status in systemd source package in Jammy:
  Won't Fix

Bug description:
  This is identical to:
  https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1881207

  It just happens to affect 22.04.1.

  I can confirm that removing the `interface-mtu XXXX` option from my
  dhcp server cures the issue.

  My netplan looks like:

  network:
    ethernets:
      enp33s0f0:
        dhcp4: true
        dhcp6: false
      enp33s0f1:
        dhcp4: true
        dhcp6: false

  This snippet is from my test when I changed the dhcpd to no longer serve MTU:

  ####
  Dec 10 00:47:42 wiyuda-echo systemd[1]: Startup finished in 6min 14.070s (firmware) + 2.667s (loader) + 25.861s (kernel) + 3min 53.796s (userspace) = 10min 36.395s.
  Dec 10 00:47:42 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:47:42 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier
  Dec 10 00:47:42 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost
  Dec 10 00:47:42 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost
  Dec 10 00:47:43 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:47:46 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
  Dec 10 00:47:46 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier
  Dec 10 00:47:46 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:47:51 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3
  Dec 10 00:47:51 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:47:51 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier
  Dec 10 00:47:51 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost
  Dec 10 00:47:51 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: Reset adapter
  Dec 10 00:47:52 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost
  Dec 10 00:47:52 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:47:52 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:47:55 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
  Dec 10 00:47:55 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier
  Dec 10 00:47:55 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3
  Dec 10 00:47:59 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier
  Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost
  Dec 10 00:47:59 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost
  Dec 10 00:47:59 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:47:59 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:48:02 wiyuda-echo systemd[1]: systemd-timedated.service: Deactivated successfully.
  Dec 10 00:48:02 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
  Dec 10 00:48:02 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier
  Dec 10 00:48:02 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:48:07 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3
  Dec 10 00:48:08 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:48:08 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: Reset adapter
  Dec 10 00:48:08 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Lost carrier
  Dec 10 00:48:08 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCP lease lost
  Dec 10 00:48:08 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv6 lease lost
  ####
    <- This is when I changed the configuration and restarted the dhcpd.
  ####
  Dec 10 00:48:08 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:48:08 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:48:11 wiyuda-echo kernel: igb 0000:21:00.0 enp33s0f0: igb: enp33s0f0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
  Dec 10 00:48:11 wiyuda-echo systemd-networkd[4866]: enp33s0f0: Gained carrier
  Dec 10 00:48:11 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:48:16 wiyuda-echo systemd-networkd[4866]: enp33s0f0: DHCPv4 address 172.16.214.138/16 via 172.16.0.3
  Dec 10 00:48:16 wiyuda-echo systemd-timesyncd[4418]: Network configuration changed, trying to establish connection.
  Dec 10 00:48:15 wiyuda-echo systemd-resolved[4868]: Clock change detected. Flushing caches.
  Dec 10 00:48:15 wiyuda-echo systemd-timesyncd[4418]: Initial synchronization to time server 172.16.0.3:123 (172.16.0.3).
  ####

  There is an upstream fix, the systemd team did update their stuff here:
  https://github.com/yuwata/systemd/commit/3be1539a9de6db3637b03b7b68686a314e4baa1f

  with issue:
  https://github.com/systemd/systemd/issues/18738

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