ML2 Mechanism Driver for Cisco Nexus1000V switch

https://blueprints.launchpad.net/neutron/+spec/ml2-n1kv-mechanism-driver

The purpose of this blueprint is to add support for Cisco Nexus1000V switch in OpenStack neutron as a ML2 mechanism driver.

Problem Description

Cisco Nexus 1000V for KVM is a distributed virtual switch that works with the Linux Kernel-based virtual machine (KVM) open source hypervisor.

  • Virtual Supervisor Module (VSM): Controller of the Cisco Nexus1000V distributed virtual switch based on Cisco NX-OS software.
  • Virtual Ethernet Module (VEM): Data plane software installed on the Compute nodes. All VEMs are controlled by VSM.
  • Network Profiles: Container for one or more networks. VLAN and VXLAN type of network profiles will be supported in the initial version.
  • Policy Profiles: Policy profiles are the primary mechanism by which network policy is defined and applied to VM ports in a Nexus 1000V system.
  • VM Network: VM Network refers to a combination of network-segment and policy-profile. It maintains a count of ports that use the above combination.

This blueprint proposes the first step in migration of the Cisco Nexus1000V monolithic plugin to a mechanism driver for ML2 plugin. This mechansim driver will interact with the VSM via REST APIs to dynamically configure and manage networking for instances created via OpenStack.

Proposed Change

The diagram below provides a high level overview of the interactions between Cisco Nexus1000V switch and OpenStack components.

Flows:

        +--------------------------+
        | Neutron Server           |
        | with ML2 Plugin          |
        |                          |
        |             +------------+
        |             |   N1KV     |
        |             | Mechanism  |                 +--------------------+
+-------|             |  Driver    |                 |                    |
|       |           +-+--+---------+    REST API     |     Cisco N1KV     |
|   +---+           | N1KV Client  +-----------------+                    |
|   |   +-----------+--------------+                 |     Virtual        |
|   |                                                |     Supervisor     |
|   |                                                |     Module         |
|   |   +--------------------------+                 |                    |
|   |   |        N1KV VEM          +-----------------+                    |
|   |   +--------------------------+                 +-+------------------+
|   |   |                          |                   |
|   +---+       Compute 1          |                   |
|       |                          |                   |
|       +--------------------------+                   |
|                                                      |
|                                                      |
|       +--------------------------+                   |
|       |        N1KV VEM          +-------------------+
|       +--------------------------+
|       |                          |
+-------+       Compute 2          |
        |                          |
        +--------------------------+

The Cisco Nexus1000V mechanism driver will handle all the postcommit events for network, subnets and ports. This data will be used to configure the VSM. The VSM and VEM will be responsible for port bring up on the compute nodes.

The mechanism driver will initialize a default network profile and a policy profile on the VSM. All networks will have a binding to this default network profile. All ports will have a binding to this default policy profile. Dynamic binding of network and policy profiles will be implemented in the future once extensions are supported for mechanism drivers.

Data Model Impact

This mechanism driver introduces four new tables which are specific to the N1KV mechanism driver.

  • NetworkProfile: Stores network profile name and type.
  • N1kvNetworkBinding: Stores the binding between network profile and network.
  • PolicyProfile: Stores policy profile name and UUID.
  • N1kvPortBinding: Stores the binding between policy profile and port.

A database migration is included to create the tables for these models.

A script to migrate data for users of monolithic plugin will be provided in the next iteration of this driver when we add support for extensions.

No existing models are changed.

REST API Impact

None.

Security Impact

None.

Notifications Impact

None.

Other End User Impact

None.

Performance Impact

The performance of Cisco N1KV ML2 mechanism driver will depend on the responsiveness of the VSM.

IPv6 Impact

None.

Other Deployer Impact

The deployer must provide the following in order to be able to connect to a VSM.

  • IP address of VSM.
  • Admin credentials (username and password) to log into VSM.
  • Add “cisco_n1kv” as a ML2 driver.
  • Add the “vlan” type driver.
  • Add the “vxlan” type driver.

These should be provided in: /opt/stack/neutron/etc/neutron/plugins/ml2/ml2_conf_cisco.ini

Example: [ml2_cisco_n1kv]

# N1KV Format. # [N1KV:<IP address of VSM>] # username=<credential username> # password=<credential password>

The Nexus1000V monolithic plugin will be deprecated once the Nexus1000V ML2 mechanism driver achieves feature parity with the monolithic plugin. Feature parity denotes full support for existing Nexus1000V specific resource and attribute extensions.

Developer Impact

None.

Community Impact

This change adds a new mechanism driver for ML2 plugin aligning with the community direction.

Alternatives

Alternative is to use the existing monolithic Nexus1000V plugin. We add this blueprint in order to interoperate with other mechanism drivers and align with community direction.

Implementation

Assignee(s)

Primary assignee:
<abhraut>
Other contributors:
<sthillma>

Work Items

Work Items can be roughly divided into the following tasks: * Mechanism driver to handle network/subnet/port CRUD requests. * N1KV Client to perform HTTP requests to the VSM. * Unit test cases to test the mechanism driver and client code. * Tempest test cases to peform functional testing.

Dependencies

Following third party library used:

Testing

Tempest Tests

Third party testing will be provided. The Cisco CI will report on all changes affecting this mechanism driver. The testing will run on a setup with an OpenStack deployment connected to a VSM and VEM.

Functional Tests

New functional tests will be added by mocking the VSM responses.

API Tests

None.

Documentation Impact

User Documentation

Configuration details for this mechanism driver.

Developer Documentation

None.