Linux bridge: 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 master 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 Linux bridge layer-2 agent and
   layer-3 agent.

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

3. In the linuxbridge_agent.ini file, configure the
   layer-2 agent.

   [linux_bridge]
   physical_interface_mappings = provider:PROVIDER_INTERFACE
   
   [vxlan]
   enable_vxlan = True
   local_ip = OVERLAY_INTERFACE_IP_ADDRESS
   
   [securitygroup]
   firewall_driver = iptables

   Warning

   By default, Linux uses UDP port 8472 for VXLAN tunnel
   traffic. This default value doesn’t follow the IANA standard, which
   assigned UDP port 4789 for VXLAN communication. As a
   consequence, if this node is part of a mixed deployment, where nodes
   with both OVS and Linux bridge must communicate over VXLAN tunnels, it
   is recommended that a line containing udp_dstport = 4789 be
   added to the [vxlan] section of all the Linux bridge agents. OVS follows
   the IANA standard.

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

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

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

   [DEFAULT]
   interface_driver = linuxbridge

5. Start the following services:

   • Linux bridge 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                    |
   +--------------------------------------+--------------------+----------+-------------------+-------+-------+---------------------------+
   | 09de6af6-c5f1-4548-8b09-18801f068c57 | Linux bridge agent | compute2 | None              | True  | UP    | neutron-linuxbridge-agent |
   | 188945d1-9e70-4803-a276-df924e0788a4 | Linux bridge agent | compute1 | None              | True  | UP    | neutron-linuxbridge-agent |
   | e76c440d-d5f6-4316-a674-d689630b629e | DHCP agent         | compute1 | nova              | True  | UP    | neutron-dhcp-agent        |
   | e67367de-6657-11e6-86a4-931cd04404bb | DHCP agent         | compute2 | nova              | True  | UP    | neutron-dhcp-agent        |
   | e8174cae-6657-11e6-89f0-534ac6d0cb5c | Metadata agent     | compute1 | None              | True  | UP    | neutron-metadata-agent    |
   | ece49ec6-6657-11e6-bafb-c7560f19197d | Metadata agent     | compute2 | None              | True  | UP    | neutron-metadata-agent    |
   | 598f6357-4331-4da5-a420-0f5be000bec9 | L3 agent           | network1 | nova              | True  | UP    | neutron-l3-agent          |
   | f4734e0f-bcd5-4922-a19d-e31d56b0a7ae | Linux bridge agent | network1 | None              | True  | UP    | neutron-linuxbridge-agent |
   | 670e5805-340b-4182-9825-fa8319c99f23 | Linux bridge agent | network2 | None              | True  | UP    | neutron-linuxbridge-agent |
   | 96224e89-7c15-42e9-89c4-8caac7abdd54 | 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-lb-selfservice with
failover of layer-3 services to another router if the master router
fails. Thus, you can reference Self-service network traffic flow
<deploy-lb-selfservice-networktrafficflow> for normal
operation.