Open Stack

I'm having an issue with Neutron under Newton in assigning routes to the 
provider network.  I would appreciate any advice on whether I am doing 
this incorrectly, or if this a bug with neutron.


I have a routed provider network that is using RFC1918 address space for 
our institution's private network.  ie:

     provider-subnet:   172.31.96.0/22   default gateway: 172.31.96.1

This subnet is routed to other subnets in the 172.16.0.0/12 address 
space, but does not have any outbound service to general internet.  To 
provide outbound NAT to instances,  I add a NATing host to the 
provider-subnet physical network and changed the default gateway to that 
host.  I then added a host route to the subnet that uses the original 
gateway as the nexthop on the generic 172.16.0.0/12 ip space:  such that:

NATing host=172.31.96.21


# openstack subnet show 066df21a-d23d-4917-8b28-d097957633dc

+-------------------+-----------------------------------------------------+

| Field             | Value                                               |

+-------------------+-----------------------------------------------------+

| allocation_pools  | 172.31.96.32-172.31.99.240                          |

| cidr              | 172.31.96.0/22                                      |

| created_at        | 2017-04-12T15:59:32Z                                |

| description       |                                                     |

| dns_nameservers   | 8.8.8.8                                             |

| enable_dhcp       | True                                                |

| gateway_ip        | 172.31.96.21                                        |

| host_routes       | destination='172.16.0.0/12', gateway='172.31.96.1'  |

| id                | 066df21a-d23d-4917-8b28-d097957633dc                |

| ip_version        | 4                                                   |

| ipv6_address_mode | None                                                |

| ipv6_ra_mode      | None                                                |

| name              | provider-campus                                     |

| network_id        | 67917c09-6cb4-4622-ae1b-9f5aef890b0f                |

| project_id        | a9746d7b6ff047dca9ac3aced978643c                    |

| project_id        | a9746d7b6ff047dca9ac3aced978643c                    |

| revision_number   | 10                                                  |

| service_types     | []                                                  |

| subnetpool_id     | None                                                |

| updated_at        | 2017-06-06T13:33:31Z                                |

+-------------------+-----------------------------------------------------+


However, when a router is added and set to the gateway on this provider 
subnet,  the included routes do not have the proper nexthop set in the 
routing table and instead just point to the default route:

# ip netns exec qrouter-da32efe2-1294-4f7e-8c47-0ef2a6d2fd39 route -n

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

0.0.0.0         172.31.96.21    0.0.0.0         UG    0      0        0 qg-5f5ca6e9-56

172.31.96.0     0.0.0.0         255.255.252.0   U     0      0        0 qg-5f5ca6e9-56

172.31.104.0    0.0.0.0         255.255.255.0   U     0      0        0 qr-db64ea28-cd


If I explicitly add the destination routes to a virtual router, 
everything works as intended:


# openstack router set --route destination='172.16.0.0/12',gateway='172.31.96.1' r2

# ip netns exec qrouter-da32efe2-1294-4f7e-8c47-0ef2a6d2fd39 route -n

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

0.0.0.0         172.31.96.21    0.0.0.0         UG    0      0        0 qg-5f5ca6e9-56

172.16.0.0      172.31.96.1     255.240.0.0     UG    0      0        0 qg-5f5ca6e9-56

172.31.96.0     0.0.0.0         255.255.252.0   U     0      0        0 qg-5f5ca6e9-56

172.31.104.0    0.0.0.0         255.255.255.0   U     0      0        0 qr-db64ea28-cd


I would rather have the route definition in the provider subnet rather 
than having to replicate the routing entries for every router instance.  
Am I missing something, or should this be working as initially intended.

Note:  running openstack newton on centos7.3.1611 using bridge plugin 
for newton:

openstack-neutron-ml2-9.2.0-1.el7.noarch
centos-release-openstack-newton-1-1.el7.noarch
python2-openstacksdk-0.9.5-1.el7.noarch
openstack-neutron-common-9.2.0-1.el7.noarch
openstack-neutron-linuxbridge-9.2.0-1.el7.noarch
python-openstackclient-3.2.1-1.el7.noarch
openstack-neutron-9.2.0-1.el7.noarch


-- 
Gary Molenkamp			Computer Science
Systems Administrator		University of Western Ontario
molenkam at uwo.ca                 http://www.csd.uwo.ca
(519) 661-2111 x86882		(519) 661-3566