os-ken/doc/source/library_ovsdb_manager.rst

OVSDB Manager library

Path: os_ken.services.protocols.ovsdb

Introduction

OS-Ken OVSDB Manager library allows your code to interact with devices speaking the OVSDB protocol. This enables your code to perform remote management of the devices and react to topology changes on them.

Please note this library will spawn a server listening on the port 6640 (the IANA registered for OVSDB protocol), but does not initiate connections from controller side. Then, to make your devices connect to OS-Ken, you need to tell the controller IP address and port to your devices.

# Show current configuration
$ ovs-vsctl get-manager

# Set manager (controller) address
$ ovs-vsctl set-manager "tcp:127.0.0.1:6640"

# If you want to specify IPv6 address, wrap ip with brackets
$ ovs-vsctl set-manager "tcp:[::1]:6640"

Also this library identifies the devices by "system-id" which should be unique, persistent identifier among all devices connecting to a single controller. Please make sure "system-id" is configured before connecting.

# Show current configuration
$ ovs-vsctl get Open_vSwitch . external_ids:system-id

# Set system-id manually
$ ovs-vsctl set Open_vSwitch . external_ids:system-id=<SYSTEM-ID>

Example

The following logs all new OVSDB connections in "handle_new_ovsdb_connection" and also provides the API "create_port" for creating a port on a bridge.

import uuid

from os_ken.base import app_manager
from os_ken.controller.handler import set_ev_cls
from os_ken.services.protocols.ovsdb import api as ovsdb
from os_ken.services.protocols.ovsdb import event as ovsdb_event


class MyApp(app_manager.OSKenApp):
    @set_ev_cls(ovsdb_event.EventNewOVSDBConnection)
    def handle_new_ovsdb_connection(self, ev):
        system_id = ev.system_id
        address = ev.client.address
        self.logger.info(
            'New OVSDB connection from system-id=%s, address=%s',
            system_id, address)

        # Example: If device has bridge "s1", add port "s1-eth99"
        if ovsdb.bridge_exists(self, system_id, "s1"):
            self.create_port(system_id, "s1", "s1-eth99")

    def create_port(self, system_id, bridge_name, name):
        new_iface_uuid = uuid.uuid4()
        new_port_uuid = uuid.uuid4()

        bridge = ovsdb.row_by_name(self, system_id, bridge_name)

        def _create_port(tables, insert):
            iface = insert(tables['Interface'], new_iface_uuid)
            iface.name = name
            iface.type = 'internal'

            port = insert(tables['Port'], new_port_uuid)
            port.name = name
            port.interfaces = [iface]

            bridge.ports = bridge.ports + [port]

            return new_port_uuid, new_iface_uuid

        req = ovsdb_event.EventModifyRequest(system_id, _create_port)
        rep = self.send_request(req)

        if rep.status != 'success':
            self.logger.error('Error creating port %s on bridge %s: %s',
                              name, bridge, rep.status)
            return None

        return rep.insert_uuids[new_port_uuid]