netplan regression 19.10 to 20.04 LTS

[Brandon McDonnell]

In Ubuntu 19.10, I have a netplan config like so: 2x gigabit and 1x 10g interface. 10g interface has several vlans. 1ge interfaces and xg vlans are placed into bridges. For example, WAN and LAN are bridged to ge interfaces in case 10g switch fails, then WAN and LAN will at least work when plugged directly into server.

If I make a change to the config, I can run `netplan generate` and `netplan apply` while system is running to update my network configuration. However, if I run a similar (same?) config under Ubuntu 20.04, I receive the following error when running `netplan apply`:

['xg0', 'br10', 'br20', 'br200', 'xg0.20', 'xg0.181', 'xg0.180', 'xg0.10', 'xg0.200', 'xg0.182']
Cannot find unique matching interface for xg0: {'macaddress': '00:02:c9:52:7a:8e'}

The config does run correctly the first time during boot! So it seems netplan now incorrectly picks up the VLAN interfaces (with same MAC) or a virtual bridge interface as a physical interface??

[Brandon McDonnell (brandonroot)]

Here's the 20.04 config, pretty sure it's the same.

And yes, it looks like 20.04 now clones xg's MAC to the virtual bridge interface by default. 19.10's br200, br20 MACs appear to be random. Sorry if this is inappropriate bug report.

[Brandon McDonnell (brandonroot)]

Tried assigning MACs to the bridges via netplan "macaddress:". `netplan generate` succeeded before reboot, but network did not come up:

br200: Could not join netdev: Cannot assign requested address

[Brandon McDonnell (brandonroot)]

While bridges are exploding, running `netplan apply` results in similar error/array as above without the bridge entries, so it seems 20.04's netplan regresses and matches child interfaces after inital `netplan apply`/boot.

I get something like

['xg0', 'xg0.20', 'xg0.181', 'xg0.180', 'xg0.10', 'xg0.200', 'xg0.182']
Cannot find unique matching interface for xg0: {'macaddress': '00:02:c9:52:7a:8e'}

This is very annoying since I sometimes add/remove/reconfigure VLANs and would like to not need to reboot after doing so.

[Brandon McDonnell (brandonroot)]

Maybe it's not a big deal, it seems I can still add/change interfaces despite the warning/error message (21.04). I did update the 20.04 machine to 21.04. Bridges are back to random addresses like 19.10 (and give "br200: Could not join netdev: Cannot assign requested address" if I try to set address manually).

[Brandon McDonnell (brandonroot)]

Here's more interesting networkd problem, using this config and Ubuntu 21.04 (I think it did this on 20.04 too) the boot takes a long time, eventually emitting

"systemd-networkd-wait-online[12149]: Event loop failed: Connection timed out"

This config works quickly on Ubuntu 19.10 with one weird exception that DNS doesn't come up until I run `netplan apply` after booting.

[Brandon McDonnell (brandonroot)]

Never mind #6, it's working, switched back from critical: no to optional: yes for the ge interfaces (since they're usually not plugged in). Was bothered by looping "managing: br20" message.

[Brandon McDonnell (brandonroot)]

For reference:
IDX LINK TYPE OPERATIONAL SETUP
  1 lo loopback carrier unmanaged
  2 ge1 ether no-carrier configuring
  3 ge0 ether no-carrier configuring
  4 xg0 ether carrier configured
  5 br10 bridge carrier configured
  6 br20 bridge routable configured
  7 br200 bridge routable configured
  8 brtv bridge no-carrier configured
  9 xg0.20 vlan enslaved configured
 10 xg0.181 vlan routable configured
 11 xg0.180 vlan routable configured
 12 xg0.10 vlan enslaved configured
 13 xg0.200 vlan enslaved configured
 14 xg0.182 vlan routable configured
 15 lxcbr0 bridge no-carrier unmanaged
 17 vethe34d06ac ether carrier unmanaged

Note for progeny, add "link-local: []" to disable IPv6 LL if you're using pfSense for WAN etc.

[Lukas Märdian (slyon)]

According to #5 this seems to be resolved. Please re-open if you feel this is still an issue.