Cannot colocate services on machines running neutron-contrail

[Greg Lutostanski]

When running neutron-contrail in "density" (smoosh) mode where services are co-located onto a nova-compute node when adding the virtual router onto the compute node other services (inside lxcs) are disconnected from the network.

Networking up until that point is fine -- the call to "contrail-provision-vrouter" is what changes the internal network topology I believe.

After this occurs in a density deployment the lxcs are still running but there are no internal bridges setup -- just the interfaces of the physical machines; so they are effectively cut off from the network.

[Robert Ayres (robert-ayres)]

When the neutron-contrail charm sets up the vrouter vhost0 interface, it will ifdown (and subsequently ifup) the default route interface. In this case the interface will be the lxc bridge (br0/lxcbr0). I think probably what's happening is the lxc veth interfaces aren't being reattached to the bridge when it's brought back up. 'brctl addif <bridge> <veth>' would probably make the said containers work again.

The charm can probably be worked so it takes a note of bridge interfaces to reattach when it brings the bridge back up. A simple workaround now is to deploy nova-compute/neutron-contrail services first and then lxc ones.

[Greg Lutostanski (lutostag)]

I will verify that the ordering works first with neutron-contrail first, then the rest of the services. If that works I will proceed to manually adding bridges back in for concurrent service deployment.

[Robert Ayres (robert-ayres)]

Have pushed a new revision 15 which contains a fix for restoring bridge interfaces. Tested locally here fine, but testing under MAAS provider would be appreciated!

[Greg Lutostanski (lutostag)]

Fixed with running in density mode with maas environment. I will read the changes you made, it seems like simply snapshotting and restoring may be a bit racy depending on how the services come up. Will get more runs in to see if we hit this problem or if it is all in my imagination.