Comment 8 for bug 1563701

Version: 2.0.0~alpha4+bzr4843-0ubuntu1

KVM hypervisor using VirtIO for NICs with the following network configuration:

ens3 (guest) bridged to em1 (host): untagged vlan for MAAS PXE
ens4 (guest) bridged to em2 (host): untagged vlan for external/Internet access
ens5 (guest) bridged to br0 (host): Bridge with a host bond as a member, no untagged access, tagged VLANs 10-16
ens5.10 (guest) bridged to br0.10 (host): tagged VLAN 10
ens5.11 (guest) bridged to br0.11 (host): tagged VLAN 11
ens5.12 (guest) bridged to br0.12 (host): tagged VLAN 12
ens5.13 (guest) bridged to br0.13 (host): tagged VLAN 13
ens5.14 (guest) bridged to br0.14 (host): tagged VLAN 14
ens5.15 (guest) bridged to br0.15 (host): tagged VLAN 15
ens5.16 (guest) bridged to br0.16 (host): tagged VLAN 16

These sysctl values are also enforced on the host:

net.bridge.bridge-nf-call-ip6tables = 0
net.bridge.bridge-nf-call-iptables = 0
net.bridge.bridge-nf-call-arptables = 0
net.bridge.bridge-nf-filter-pppoe-tagged = 0
net.bridge.bridge-nf-filter-vlan-tagged = 0

This host setup might seem a little strange or over the top, but what it enables is a guest configuration that resembles something we can expect to see in production, ie:

untagged interface for MAAS PXE
untagged interface for external/Internet access (the specifics of this interface are largely irrelevant though)
tagged interfaces for OpenStack MAAS/Juju spaces

It bears reiterating that the first/primary MAAS server *does* recognise all the correct interfaces. It is only the seconday MAAS server that seems not to, and they have the same config and the same physical host with the same VM configuration.
Let me know if you need