openstack
/
neutron
Code Issues Proposed changes
neutron/neutron/plugins/ml2/drivers/l2pop
History
Darragh O'Reilly 93e9dc5426 ovs agent: signal to plugin if tunnel refresh needed 
Currently the ovs agent calls update_device_list with the
agent_restarted flag set only on the first loop iteration. Then the
server knows to send the l2pop flooding entries for the network to
the agent. But when a compute node with many instances on many
networks reboots, it takes time to readd all the active devices and
some may be readded after the first loop iteration. Then the server
can fail to send the flooding entries which means there will be no
flood_to_tuns flow and broadcasts like dhcp will fail.

This patch fixes that by renaming the agent_restarted flag to
refresh_tunnels and setting it if the agent has not received the
flooding entries for the network.

Change-Id: I607aa8fa399e72b037fd068ad4f02b6210e57e91
Closes-Bug: #1853613
 		2020-01-09 14:18:43 +00:00
..
rpc_manager Removed deprecated class LocalVLANMapping 2016-11-07 20:24:06 +00:00
README Implement local ARP responder onto OVS agent 2014-05-19 21:42:11 +02:00
__init__.py Empty files should not contain copyright or license 2014-10-20 00:50:32 +00:00
db.py Fix pep8 E128 warnings in non-test code 2019-03-12 21:22:33 +00:00
mech_driver.py ovs agent: signal to plugin if tunnel refresh needed 2020-01-09 14:18:43 +00:00
rpc.py remove neutron.common.rpc 2019-02-06 11:05:55 -07:00

README 

Neutron ML2 l2 population Mechanism Drivers

l2 population (l2pop) mechanism drivers implements the ML2 driver to improve
open source plugins overlay implementations (VXLAN with Linux bridge and
GRE/VXLAN with OVS). This mechanism driver is implemented in ML2 to propagate
the forwarding information among agents using a common RPC API.

More informations could be found on the wiki page [1].

VXLAN Linux kernel:
-------------------
The VXLAN Linux kernel module provide all necessary functionalities to populate
the forwarding table and local ARP responder tables. This module appears on
release 3.7 of the vanilla Linux kernel in experimental:
- 3.8: first stable release, no edge replication (multicast necessary),
- 3.9: edge replication only for the broadcasted packets,
- 3.11: edge replication for broadcast, multicast and unknown packets.

Note: Some distributions (like RHEL) have backported this module on precedent
      kernel version.

OpenvSwitch:
------------
The OVS OpenFlow tables provide all of the necessary functionality to populate
the forwarding table and local ARP responder tables.
A wiki page describe how the flow tables did evolve on OVS agents:
- [2] without local ARP responder
- [3] with local ARP responder. /!\ This functionality is only available since
                                    the development branch 2.1. It's possible
                                    to disable (enable by default) it through
                                    the flag 'arp_responder'. /!\


Note: A difference persists between the LB and OVS agents when they are used
      with the l2-pop mechanism driver (and local ARP responder available). The
      LB agent will drop unknown unicast (VXLAN bridge mode), whereas the OVS
      agent will flood it.

[1] https://wiki.openstack.org/wiki/L2population_blueprint
[2] https://wiki.openstack.org/wiki/Ovs-flow-logic#OVS_flows_logic
[3] https://wiki.openstack.org/wiki/Ovs-flow-logic#OVS_flows_logic_with_local_ARP_responder