[2.5] Composing a VM with an interface attached to a (macvtap) network (on a KVM host NIC that is not a bridge) resulted in disconnect interface

[Vladimir Grevtsev]

Screencast: https://www.dropbox.com/s/g5by5qpowmvt53k/0%3F8AL%200%3AB82AB8%200%20M%3A%4005%202018-12-04%202%2014.39.56.mov

MAAS info: https://pastebin.canonical.com/p/bTFQHXn8gN/

Expected behaviour: New-created pod should be assigned with all IP addresses specified in "Compose" page, not only first one.

To provide more context:

1. MAAS had multiple interfaces but only two were used for the KVM host.
2. The KVM host was also a rack controller.
3. The interfaces were a bridge and a VLAN interface, e.g.:

br0
bond0.13

4. When creating a VM with 2 NICs, one on the same network as br0 and the other as the same network of bond0.13, the resulting VM had two interfaces, one attached and one disconnected. THe disconnect was the one attached to bond0.13.

5. After creating a bridge on top of bond0.13, MAAS was able to successfully configure the VM's interface with fabric/vlan/subnet/ip mode.

[Andres Rodriguez (andreserl)]

Hi Vladimir,

Could you provide:

1. /var/log/maas/*.log while you are composing the machine
2. After the machine has successfully commissioned, what's the result of the interfaces?

[Vladimir Grevtsev (vlgrevtsev)]

After the call with team we have identified a root cause: second NIC has been configured not as bridge, but as regular interface - that's why MAAS failed to auto-detect corresponding VLAN.

[Andres Rodriguez (andreserl)]

Note that the work-around for this issue is to use bridge interfaces on the KVM host where you want to attach VM interfaces to.