netplan fails to remove OVS vlan interfaces

[Brian Turek]

netplan fails to delete OVS vlan interfaces that were previously defined but were then removed from the configuration. The underlying problem appears to be that the "ovs-vsctl iface-to-br" command used (https://github.com/canonical/netplan/blob/331ca01908b68446a9a1f395616136678e617a1a/netplan/cli/ovs.py#L147) to test whether an interface is bonded or a vlan fails on "fake bridges" (this is how OVS defines vlans) which then causes it be treated incorrectly as a bonded interface. My testing seems to indicate the "ovs-vsctl br-exists" command may be a better choice for this test.

As a bare bones reproducible:

$ cat /etc/netplan/00-test.yaml
network:
  version: 2
  renderer: networkd
  openvswitch: {}
  ethernets:
    enp0s8: {} # physical ethernet interface
  bridges:
    br0:
      interfaces: [enp0s8]
      openvswitch: {}
  vlans:
    enp0s8_999:
      id: 999
      link: br0
      openvswitch: {}

$ sudo netplan apply
$ sudo ovs-vsctl show
709aacc0-aa1d-4888-ae99-e3096a99620a
    Bridge br0
        fail_mode: standalone
        Port br0
            Interface br0
                type: internal
        Port enp0s8_999
            tag: 999
            Interface enp0s8_999
                type: internal
        Port enp0s8
            Interface enp0s8
    ovs_version: "2.16.0"

# This does not work and note the error message
$ sudo ovs-vsctl iface-to-br enp0s8_999
ovs-vsctl: no interface named enp0s8_999

# Make edits to /etc/netplan/00-test.yaml to remove the vlan interface
$ cat /etc/netplan/00-test.yaml
network:
  version: 2
  renderer: networkd
  openvswitch: {}
  ethernets:
    enp0s8: {} # physical ethernet interface
  bridges:
    br0:
      interfaces: [enp0s8]
      openvswitch: {}

# Note the below has the same error message as the example iface-to-br command
$ sudo netplan apply
ovs-vsctl: no interface named enp0s8_999

$ sudo ovs-vsctl show
709aacc0-aa1d-4888-ae99-e3096a99620a
    Bridge br0
        fail_mode: standalone
        Port br0
            Interface br0
                type: internal
        Port enp0s8_999
            tag: 999
            Interface enp0s8_999
                type: internal
        Port enp0s8
            Interface enp0s8
    ovs_version: "2.16.0"

# Interface is still defined

[Brian Turek (brian-turek)]

I just submitted a PR on the Github repository at https://github.com/canonical/netplan/pull/256