neutron/neutron/plugins/ml2
LIU Yulong a5244d6d44 More accurate agent restart state transfer
Ovs-agent can be very time-consuming in handling a large number
of ports. At this point, the ovs-agent status report may have
exceeded the set timeout value. Some flows updating operations
will not be triggerred. This results in flows loss during agent
restart, especially for hosts to hosts of vxlan tunnel flow.

This fix will let the ovs-agent explicitly, in the first rpc loop,
indicate that the status is restarted. Then l2pop will be required
to update fdb entries.

Closes-Bug: #1813703
Closes-Bug: #1813714
Closes-Bug: #1813715
Closes-Bug: #1794991
Closes-Bug: #1799178

Change-Id: I8edc2deb509216add1fb21e1893f1c17dda80961
2019-03-21 15:12:31 +00:00
..
common Add bulk port creation of DB objects 2018-11-29 10:00:47 -05:00
drivers More accurate agent restart state transfer 2019-03-21 15:12:31 +00:00
extensions Fix pep8 E128 warnings in non-test code 2019-03-12 21:22:33 +00:00
README Metaplugin removal 2015-07-23 19:05:05 +09:00
__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
driver_context.py Drive binding by placement allocation 2019-03-09 22:03:51 +00:00
managers.py Merge "Drive binding by placement allocation" 2019-03-10 12:54:16 +00:00
models.py Pluralize binding relationship in Port 2018-07-13 19:37:36 -05:00
ovo_rpc.py use context manager from neutron-lib 2018-10-24 07:18:46 -06:00
plugin.py Fix pep8 E128 warnings in non-test code 2019-03-12 21:22:33 +00:00
rpc.py More accurate agent restart state transfer 2019-03-21 15:12:31 +00:00

README

The Modular Layer 2 (ML2) plugin is a framework allowing OpenStack
Networking to simultaneously utilize the variety of layer 2 networking
technologies found in complex real-world data centers. It supports the
Open vSwitch, Linux bridge, and Hyper-V L2 agents, replacing and
deprecating the monolithic plugins previously associated with those
agents, and can also support hardware devices and SDN controllers. The
ML2 framework is intended to greatly simplify adding support for new
L2 networking technologies, requiring much less initial and ongoing
effort than would be required for an additional monolithic core
plugin. It is also intended to foster innovation through its
organization as optional driver modules.

The ML2 plugin supports all the non-vendor-specific neutron API
extensions, and works with the standard neutron DHCP agent. It
utilizes the service plugin interface to implement the L3 router
abstraction, allowing use of either the standard neutron L3 agent or
alternative L3 solutions. Additional service plugins can also be used
with the ML2 core plugin.

Drivers within ML2 implement separately extensible sets of network
types and of mechanisms for accessing networks of those
types. Multiple mechanisms can be used simultaneously to access
different ports of the same virtual network. Mechanisms can utilize L2
agents via RPC and/or interact with external devices or
controllers. By utilizing the multiprovidernet extension, virtual
networks can be composed of multiple segments of the same or different
types. Type and mechanism drivers are loaded as python entrypoints
using the stevedore library.

Each available network type is managed by an ML2 type driver.  Type
drivers maintain any needed type-specific network state, and perform
provider network validation and tenant network allocation. As of the
havana release, drivers for the local, flat, vlan, gre, and vxlan
network types are included.

Each available networking mechanism is managed by an ML2 mechanism
driver. All registered mechanism drivers are called twice when
networks, subnets, and ports are created, updated, or deleted. They
are first called as part of the DB transaction, where they can
maintain any needed driver-specific state. Once the transaction has
been committed, they are called again, at which point they can
interact with external devices and controllers. Mechanism drivers are
also called as part of the port binding process, to determine whether
the associated mechanism can provide connectivity for the network, and
if so, the network segment and VIF driver to be used. The havana
release includes mechanism drivers for the Open vSwitch, Linux bridge,
and Hyper-V L2 agents, and for vendor switches/controllers/etc.
It also includes an L2 Population mechanism driver that
can help optimize tunneled virtual network traffic.

For additional information regarding the ML2 plugin and its collection
of type and mechanism drivers, see the OpenStack manuals and
http://wiki.openstack.org/wiki/Neutron/ML2.