7fe0de8328
The ML2 README file was slightly out of date with all of the H2 changes which went in around GRE and VXLAN tunneling. This patch updates it to reflect what the code is capable of currently. Fixes bug 1202743. Change-Id: I578c1b62115f298c9de32d62161171fd2f3f5b7c
85 lines
3.8 KiB
Plaintext
85 lines
3.8 KiB
Plaintext
The Modular Layer 2 (ml2) plugin is a framework allowing OpenStack
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Networking to simultaneously utilize the variety of layer 2 networking
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technologies found in complex real-world data centers. It currently
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works with the existing openvswitch, linuxbridge, and hyperv L2
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agents, and is intended to replace and deprecate the monolithic
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plugins associated with those L2 agents. The ml2 framework is also
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intended to greatly simplify adding support for new L2 networking
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technologies, requiring much less initial and ongoing effort than
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would be required to add a new monolithic core plugin.
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Drivers within ml2 implement separately extensible sets of network
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types and of mechanisms for accessing networks of those types. Unlike
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with the metaplugin, multiple mechanisms can be used simultaneously to
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access different ports of the same virtual network. Mechanisms can
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utilize L2 agents via RPC and/or use mechanism drivers to interact
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with external devices or controllers. Virtual networks can be composed
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of multiple segments of the same or different types. Type and
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mechanism drivers are loaded as python entrypoints using the stevedore
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library.
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Each available network type is managed by an ml2 TypeDriver.
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TypeDrivers maintain any needed type-specific network state, and
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perform provider network validation and tenant network allocation. The
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initial ml2 version includes drivers for the local, flat, vlan, gre,
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and vxlan network types.
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RPC callback and notification interfaces support interaction with L2,
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DHCP, and L3 agents. This version has been tested with the existing
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openvswitch and linuxbridge plugins' L2 agents, and should also work
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with the hyperv L2 agent. A modular agent may be developed as a
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follow-on effort.
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Support for mechanism drivers is currently a work-in-progress in
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pre-release Havana versions, and the interface is subject to change
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before the release of Havana. MechanismDrivers are currently called
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both inside and following DB transactions for network and port
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create/update/delete operations. In a future version, they will also
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called to establish a port binding, determining the VIF type and
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network segment to be used.
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The database schema and driver APIs support multi-segment networks,
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but the client API for multi-segment networks is not yet implemented.
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ML2 supports devstack at the moment with either the Open vSwitch or
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LinuxBridge L2 agents for local, flat, vlan, or gre network types.
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Note that ml2 does not yet work with nova's GenericVIFDriver, so it is
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necessary to configure nova to use a specific driver compatible with
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the L2 agent deployed on each compute node. Additionally, support for
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configuring additional ML2 items is a work in progress in devstack.
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This includes configuring VXLAN support for ML2 with the OVS agent.
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Note that the ml2 plugin is new and should be conidered experimental
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at this point. It is undergoing rapid development, so driver APIs and
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other details are likely to change during the havana development
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cycle.
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Follow-on tasks required for full ml2 support in havana, including
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parity with the existing monolithic openvswitch, linuxbridge, and
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hyperv plugins:
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- Additional unit tests
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- Implement MechanismDriver port binding so that a useful
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binding:vif_type value is returned for nova's GenericVIFDriver based
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on the binding:host_id value and information from the agents_db
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Additional follow-on tasks expected for the havana release:
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- Extend providernet extension API to support multi-segment networks
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The following MechanismDrivers are actively under development for the
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Havana release:
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- Arista Driver:
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https://blueprints.launchpad.net/quantum/+spec/sukhdev-8
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- Cisco Nexus Driver:
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https://blueprints.launchpad.net/quantum/+spec/ml2-md-cisco-nexus
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- OpenDaylight Driver:
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https://blueprints.launchpad.net/quantum/+spec/ml2-opendaylight-mechanism-driver
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- Tail-f NCS Driver:
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https://blueprints.launchpad.net/quantum/+spec/tailf-ncs
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