Open vSwitch: High availability using DVR supports augmentation using Virtual Router Redundancy Protocol (VRRP). Using this configuration, virtual routers support both the --distributed and --ha options.
Similar to legacy HA routers, DVR/SNAT HA routers provide a quick fail over of the SNAT service to a backup DVR/SNAT router on an l3-agent running on a different node.
SNAT high availability is implemented in a manner similar to the Linux bridge: High availability using VRRP and Open vSwitch: High availability using VRRP examples where keepalived uses VRRP to provide quick failover of SNAT services.
During normal operation, the master router periodically transmits heartbeat packets over a hidden project network that connects all HA routers for a particular project.
If the DVR/SNAT backup router stops receiving these packets, it assumes failure of the master DVR/SNAT router and promotes itself to master router by configuring IP addresses on the interfaces in the snat namespace. In environments with more than one backup router, the rules of VRRP are followed to select a new master router.
Note
Experimental feature or incomplete documentation.
The basic deployment model consists of one controller node, two or more network nodes, and multiple computes nodes.
Add the following to /etc/neutron/neutron.conf:
[DEFAULT]
core_plugin = ml2
service_plugins = router
allow_overlapping_ips = True
router_distributed = True
l3_ha = True
l3_ha_net_cidr = 169.254.192.0/18
max_l3_agents_per_router = 3
min_l3_agents_per_router = 2
When the router_distributed = True flag is configured, routers created by all users are distributed. Without it, only privileged users can create distributed routers by using --distributed True.
Similarly, when the l3_ha = True flag is configured, routers created by all users default to HA.
It follows that with these two flags set to True in the configuration file, routers created by all users will default to distributed HA routers (DVR HA).
The same can explicitly be accomplished by a user with administrative credentials setting the flags in the router-create command:
$ neutron router-create name-of-router --distributed=True --ha=True
Note
The max_l3_agents_per_router and min_l3_agents_per_router determine the number of backup DVR/SNAT routers which will be instantiated.
Add the following to /etc/neutron/plugins/ml2/ml2_conf.ini:
[ml2]
type_drivers = flat,vxlan
tenant_network_types = vxlan
mechanism_drivers = openvswitch,l2population
extension_drivers = port_security
[ml2_type_flat]
flat_networks = external
[ml2_type_vxlan]
vni_ranges = MIN_VXLAN_ID:MAX_VXLAN_ID
Replace MIN_VXLAN_ID and MAX_VXLAN_ID with VXLAN ID minimum and maximum values suitable for your environment.
Note
The first value in the tenant_network_types option becomes the default project network type when a regular user creates a network.
Configure the Open vSwitch agent. Add the following to /etc/neutron/plugins/ml2/ml2_conf.ini:
[ovs]
local_ip = TUNNEL_INTERFACE_IP_ADDRESS
bridge_mappings = external:br-ex
[agent]
enable_distributed_routing = True
tunnel_types = vxlan
l2_population = True
[securitygroup]
firewall_driver = neutron.agent.linux.iptables_firewall.OVSHybridIptablesFirewallDriver
Replace TUNNEL_INTERFACE_IP_ADDRESS with the IP address of the interface that handles VXLAN project networks.
Configure the L3 agent. Add the following to /etc/neutron/l3_agent.ini:
[DEFAULT]
ha_vrrp_auth_password = password
interface_driver = openvswitch
external_network_bridge =
agent_mode = dvr_snat
Note
The external_network_bridge option intentionally contains no value.
Configure the Open vSwitch agent. Add the following to /etc/neutron/plugins/ml2/ml2_conf.ini:
[ovs]
local_ip = TUNNEL_INTERFACE_IP_ADDRESS
bridge_mappings = external:br-ex
[agent]
enable_distributed_routing = True
tunnel_types = vxlan
l2_population = True
[securitygroup]
firewall_driver = neutron.agent.linux.iptables_firewall.OVSHybridIptablesFirewallDriver
Configure the L3 agent. Add the following to /etc/neutron/l3_agent.ini:
[DEFAULT]
interface_driver = openvswitch
external_network_bridge =
agent_mode = dvr
Replace TUNNEL_INTERFACE_IP_ADDRESS with the IP address of the interface that handles VXLAN project networks.
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