netplan cannot create interfaces with the same VLAN tag.

[Alex Mercer]

netplan cannot create interfaces with the same VLAN tag.

Due to the fact that netplan creates a bridge instead of an OVS port for creating OVS VLAN interfaces, it is unable to create VLAN interfaces with the same tag.

root@node-1:/opt/ceph-binnary-deploy-0.5.1# systemctl status netplan-ovs-br_test.service
● netplan-ovs-br_test.service - OpenVSwitch configuration for br_test
     Loaded: loaded (/run/systemd/system/netplan-ovs-br_test.service; enabled-runtime; vendor preset: enabled)
     Active: failed (Result: exit-code) since Tue 2023-08-15 13:57:57 CST; 54s ago
    Process: 3750298 ExecStart=/usr/bin/ovs-vsctl --may-exist add-br br_test br_bond1 304 (code=exited, status=1/FAILURE)
   Main PID: 3750298 (code=exited, status=1/FAILURE)

Aug 15 13:57:57 node-1.mgmt.osk systemd[1]: Starting OpenVSwitch configuration for br_test...
Aug 15 13:57:57 node-1.mgmt.osk ovs-vsctl[3750298]: ovs|00001|vsctl|INFO|Called as /usr/bin/ovs-vsctl --may-exist add-br br_test br_bond1 304
Aug 15 13:57:57 node-1.mgmt.osk ovs-vsctl[3750298]: ovs|00002|db_ctl_base|ERR|bridge br_bond1 already has a child VLAN bridge br_tunnel on VLAN 304
Aug 15 13:57:57 node-1.mgmt.osk ovs-vsctl[3750298]: ovs-vsctl: bridge br_bond1 already has a child VLAN bridge br_tunnel on VLAN 304
Aug 15 13:57:57 node-1.mgmt.osk systemd[1]: netplan-ovs-br_test.service: Main process exited, code=exited, status=1/FAILURE
Aug 15 13:57:57 node-1.mgmt.osk systemd[1]: netplan-ovs-br_test.service: Failed with result 'exit-code'.
Aug 15 13:57:57 node-1.mgmt.osk systemd[1]: Failed to start OpenVSwitch configuration for br_test.

[Lukas Märdian (slyon)]

Thanks for your report.
Could you please provide more data of how to reproduce this issue? E.g. provide the Netplan YAML configuration that you're using in the example above?

[Launchpad Janitor (janitor)]

[Expired for netplan because there has been no activity for 60 days.]

[Alex Mercer (flashadow)]

I found the source of the bug (please see the attached code for details), ovs allows the creation of ports with the same vlan id, but not bridges with the same vlan id. so the code to create the vlan interface should be '--may-exist add-port '.

[Lukas Märdian (slyon)]

Thank you for your analysis! So you're suggesting we should be using an OVS port instead of an OVS bridge to setup the VLAN device. That's something we will consider in the future.

Would you mind creating a pull-request about it at https://github.com/canonical/netplan/pulls ?

[Alex Mercer (flashadow)]

Yes, I'm looking forward to this feature.