DHCP not working on demo-net

DHCP-agent works in a separate namespace but is connected to br-int in ovs, after creating a demo-net it can be seen that an interface on which dhcp (tap3b4d7bf0-12) server works is assigned to VLAN 4095 (so called “dead-vlan”) on the br-int making it inaccessible for a running instance which has an interface in demo-net.

Changing tag statically to 1 (same tag as used by qr* interface where DHCP requests from an example instance are seen with tcpdump):

Does not solve the problem, DHCP requests reach DHCP agent and are replied but replies are not forwarded to the instance (probably some more static changes are required in OVS)

DHCP port (in this example 10.0.0.2) is visible in neutron as DOWN:

Solution:

Rather simple one. Disable and enable back DHCP service on the network (I did it from horizon) -> after this DHCP port’s status changes to ACTIVE (and probably something more internally in OVS is changed so as to make DHCP replies being forwarded properly to the instance).

Instance not started due to Neutron misconfiguration on Ubuntu 14.04

While attempting to start instance the following problem appears:

/var/log/nova/nova-compute.log

 /var/log/neutron/server.log

Solution:

Add in /etc/nova/nova.conf in [DEFAULT] section:

Problem described here:

https://ask.openstack.org/en/question/26938/virtualinterfacecreateexception-virtual-interface-creation-failed/