Comment 0 for bug 1636963

Service Subnets[1] were added in Newton.

The TL;DR is that a subnet can be created/updated with one or more service_types corresponding to a port device owner. If a subnet has one or more service_types, then only ports with a matching device owner can be created on the subnet.

If a service subnet is created with dhcp enabled, automatic dhcp port creation fails, because the port device owner does not match the subnet's service_types.

The port creation is re-attempted over and over, and the subnet remains without dhcp.

Steps to recreate:

NOTE: THIS REQUIRES INSTALLING OPENSTACKCLIENT FROM MASTER

$ openstack network create test-net

$ openstack subnet create test-subnet --subnet-range 10.1.0.0/24 --service-type compute:nova \
  --network test-net

Then take a look in the q-svc logs.

[1] http://docs.openstack.org/draft/networking-guide/config-service-subnets.html