Open vSwitch: High availability using VRRP

Prerequisites

Add one network node with the following components:

• Three network interfaces: management, provider, and overlay.
• OpenStack Networking layer-2 agent, layer-3 agent, and any
  dependencies.

Architecture

The following figure shows components and connectivity for one
self-service network and one untagged (flat) network. The primary router
resides on network node 1. In this particular case, the instance resides
on the same compute node as the DHCP agent for the network. If the DHCP
agent resides on another compute node, the latter only contains a DHCP
namespace and Linux bridge with a port on the overlay physical network
interface.

Example configuration

Use the following example configuration as a template to add support
for high-availability using VRRP to an existing operational environment
that supports self-service networks.

Controller node

1. In the neutron.conf file:

   • Enable VRRP.

     [DEFAULT]
     l3_ha = True

2. Restart the following services:
   • Server

Network node 1

No changes.

Network node 2

1. Install the Networking service OVS layer-2 agent and layer-3
   agent.

2. Install OVS.

3. In the neutron.conf file, configure common
   options:

4. Start the following services:

   • OVS

5. Create the OVS provider bridge br-provider:

   $ ovs-vsctl add-br br-provider

6. Add the provider network interface as a port on the OVS provider
   bridge br-provider:

   $ ovs-vsctl add-port br-provider PROVIDER_INTERFACE

   Replace PROVIDER_INTERFACE with the name of the
   underlying interface that handles provider networks. For example,
   eth1.

7. In the openvswitch_agent.ini file, configure the
   layer-2 agent.

   [ovs]
   bridge_mappings = provider:br-provider
   local_ip = OVERLAY_INTERFACE_IP_ADDRESS
   
   [agent]
   tunnel_types = vxlan
   l2_population = true
   
   [securitygroup]
   firewall_driver = iptables_hybrid

   Replace OVERLAY_INTERFACE_IP_ADDRESS with the IP address
   of the interface that handles VXLAN overlays for self-service
   networks.

8. In the l3_agent.ini file, configure the layer-3
   agent.

   [DEFAULT]
   interface_driver = openvswitch

9. Start the following services:

   • Open vSwitch agent
   • Layer-3 agent

Compute nodes

No changes.

Verify service operation

1. Source the administrative project credentials.

2. Verify presence and operation of the agents.

   $ openstack network agent list
   +--------------------------------------+--------------------+----------+-------------------+-------+-------+---------------------------+
   | ID                                   | Agent Type         | Host     | Availability Zone | Alive | State | Binary                    |
   +--------------------------------------+--------------------+----------+-------------------+-------+-------+---------------------------+
   | 1236bbcb-e0ba-48a9-80fc-81202ca4fa51 | Metadata agent     | compute2 | None              | True  | UP    | neutron-metadata-agent    |
   | 457d6898-b373-4bb3-b41f-59345dcfb5c5 | Open vSwitch agent | compute2 | None              | True  | UP    | neutron-openvswitch-agent |
   | 71f15e84-bc47-4c2a-b9fb-317840b2d753 | DHCP agent         | compute2 | nova              | True  | UP    | neutron-dhcp-agent        |
   | 8805b962-de95-4e40-bdc2-7a0add7521e8 | L3 agent           | network1 | nova              | True  | UP    | neutron-l3-agent          |
   | a33cac5a-0266-48f6-9cac-4cef4f8b0358 | Open vSwitch agent | network1 | None              | True  | UP    | neutron-openvswitch-agent |
   | a6c69690-e7f7-4e56-9831-1282753e5007 | Metadata agent     | compute1 | None              | True  | UP    | neutron-metadata-agent    |
   | af11f22f-a9f4-404f-9fd8-cd7ad55c0f68 | DHCP agent         | compute1 | nova              | True  | UP    | neutron-dhcp-agent        |
   | bcfc977b-ec0e-4ba9-be62-9489b4b0e6f1 | Open vSwitch agent | compute1 | None              | True  | UP    | neutron-openvswitch-agent |
   | 7f00d759-f2c9-494a-9fbf-fd9118104d03 | Open vSwitch agent | network2 | None              | True  | UP    | neutron-openvswitch-agent |
   | b28d8818-9e32-4888-930b-29addbdd2ef9 | L3 agent           | network2 | nova              | True  | UP    | neutron-l3-agent          |
   +--------------------------------------+--------------------+----------+-------------------+-------+-------+---------------------------+

Create initial networks

Verify network operation

Verify failover operation

Keepalived VRRP health check

Network traffic flow

This high-availability mechanism simply augments deploy-ovs-selfservice with
failover of layer-3 services to another router if the primary router
fails. Thus, you can reference Self-service network traffic flow
<deploy-ovs-selfservice-networktrafficflow> for normal
operation.