This document discusses Neutron networking status in OpenStack, including features like Distributed Virtual Router (DVR) support. DVR allows distributed routing to remove bottlenecks and enable one-hop east-west traffic between VMs on different hypervisors. The document provides configuration options for enabling DVR and an example multi-node Devstack configuration for testing DVR on compute and network nodes. It also includes diagrams illustrating how DVR works to deliver traffic between VMs on different networks and hypervisors.

1. Neutron
Distributed Virtual Router
Edgar Magana
Cloud Operations Architect

2. Acknowledgments
Big Thanks to Great Developers in OpenStack
Community & OpenStack Foundation.
Information presented here are sourced from my own
experience as OpenStack developer/user and from
OpenStack Foundation Documents & Community.
Views and Technical points expressed here are
solely presenter’s and doesn’t reflect his employer
views/positions or OpenStack Foundation in anyway.

3. Networking Status (Neutron)
 nova-network Parity
– Feature parity with nova-network in progress
– Initial migration path -- initial path for nova-network deprecation
 L3 Enhancements
– Multiple L3 agents
– HA through plugins & keepalived
– Each router created is assigned to 2 or more agents
 IPv6
– Next generation of IP routing
– 2001:0db8:85a3:0042:1000:8a2e:0370:7334 rather than 10.28.255.168
– Address assignment
– SLAAC
– Stateful DHCP
– Stateless DHCP
– Router advertisement through RADVD

4. Networking Status (Neutron)
 DVR
– Uses L3 HA
– Removes bottleneck in east-west traffic
– Shares OVS route information across virtual routers
– One-hop traffic for VMs on different hypervisors
– Requires OVS on ML2 plugin
 New plugins/Drivers
– OpenContrail plugin
– A10 Networks LBaaS driver
– Arista L3 routing plugin
– Big Switch L3 routing plugin
– Brocade L3 routing plugin
– Cisco APIC ML2 Driver (including a L3 routing plugin)
– Cisco CSR L3 routing plugin
– Freescale SDN ML2 Mechanism

5. OpenStack Networking Deployment

6. Network Node Internals

7. DVR Support in Juno
 The new Enhanced L3 Agent can operate in 3 different modes:
1. Legacy (default for backward compatibility)
 Centralized routing only
 Runs on Network Nodes
2. DVR
 Supports distributed routing
 Runs on Compute Nodes
3. DVR_SNAT
 Supports legacy centralized routing, DVR and centralized SNAT
 Runs on either Network/Service Node or Compute Nodes
 Each mode adds new support for certain features while continuing to support
the other features but is dependent on the l3-agent scheduler.

8. Neutron – DVR Config Options
 neutron.conf
[DEFAULT]
router_distributed = False (True = DVR mode)
dvr_base_mac = fa:16:3f:00:00:00
 ovs_neutron_plugin.ini
[agent]
enable_distributed_routing = False (True = The l2 agent runs in DVR mode)
 l3_agent.ini
[DEFAULT]
agent_mode = legacy
 dvr
 dvr_snat

9. DVR – Devstack Multi-Node
Controller/Network(SNAT)
HOST_IP=172.16.232.137
disable_service n-net
enable_service neutron
enable_service tempest
enable_service q-svc
enable_service q-agt
enable_service q-dhcp
enable_service q-l3
enable_service q-meta
enable_service n-cpu
MYSQL_PASSWORD=nova
RABBIT_PASSWORD=nova
SERVICE_TOKEN=nova
SERVICE_PASSWORD=nova
ADMIN_PASSWORD=nova
LOGDAYS=1
Q_PLUGIN=ml2
ENABLE_TENANT_TUNNELS=True
TENANT_TUNNEL_RANGE=50:100
Q_ML2_TENANT_NETWORK_TYPE=vxlan
Q_DVR_MODE=dvr_snat
VNCSERVER_LISTEN=$HOST_IP
VNCSERVER_PROXYCLIENT_ADDRESS=$HOST_IP
MULTI_HOST=1
Compute/Routing
HOST_IP=172.16.232.138
SERVICE_HOST=172.16.232.137
MYSQL_HOST=$SERVICE_HOST
RABBIT_HOST=$SERVICE_HOST
GLANCE_HOSTPORT=$SERVICE_HOST:9292
MYSQL_PASSWORD=nova
ADMIN_PASSWORD=nova
SERVICE_PASSWORD=nova
SERVICE_TOKEN=nova
RABBIT_PASSWORD=nova
ENABLED_SERVICES=n-cpu,neutron,n-novnc,q-agt,q-l3
Q_PLUGIN=ml2
ENABLE_TENANT_TUNNELS=True
TENANT_TUNNEL_RANGE=50:100
Q_ML2_TENANT_NETWORK_TYPE=vxlan
Q_DVR_MODE=dvr
VNCSERVER_LISTEN=$HOST_IP
VNCSERVER_PROXYCLIENT_ADDRESS=$HOST_IP
MULTI_HOST=1

10. IP Network Namespaces
After creating a few networks and routers:
openstack-dev:~/devstack$ sudo ip netns
qdhcp-2e9facd9-92d3-4d71-9c80-6d3992b6751b
qdhcp-ea73f4b4-d753-4d2b-9089-e0dc65cfea2b
qrouter-c64a1a02-6425-4252-ba89-3146647c564f
snat-375d717f-afd3-4427-878d-4c38303e40f2
qrouter-375d717f-afd3-4427-878d-4c38303e40f2
openstack-dev-compute:~/devstack$ sudo ip netns
qrouter-c64a1a02-6425-4252-ba89-3146647c564f

11. DVR in Action
LEGEND
Tenant 1 has two Networks - RED & GREEN
Tenant 2 has one Network - ORANGE
11. Deliver to VM 2:
srcMac = green-Mac, destMac = VM2, Network = green
IR
IR
vm1 vm3
vm6 vm7 1. Data frame with
srcMac = VM1, destMac = red-Mac, Network = red
br-int-cn1
4. Set destMac:
srcMac = VM1, destMac = VM2, Network = green
5. Set srcMac:
srcMac = green-Mac, destMac = VM2, Network = green
br-tun-cn1
vm2 vm4
br-int-cn2
br-tun-cn2
vm5
Data Network
2. br-int forwards to IR
10. Swap in Gateway Mac:
srcMac = green-Mac, destMac = VM2, Network = green
9. Usual Virtual switching
srcMac = dvr-cn1-Mac, destMac = VM2, Network = green
3. Change network:
srcMac = VM1, destMac = red-Mac, Network = green
6. Dec TTL and fwd:
srcMac = green-Mac, destMac = VM2, Network = green
7. Swap out Gateway Mac:
srcMac = dvr-cn1-Mac, destMac = VM2, Network = green
8. Usual Virtual switching :
srcMac = dvr-cn1-Mac, destMac = VM2, Network = green
source: HP Neutron Team

12. Thank you!
Details:
https://etherpad.openstack.org/p/kilo-summit-ops-dvr
http://www.slideshare.net/emaganap
twitter: emaganap