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Taikun OCP Guide

Table of Contents

Trunking

The network trunk service allows multiple networks to be connected to
an instance using a single virtual NIC (vNIC). Multiple networks can be
presented to an instance by connecting it to a single port.

Operation

Network trunking consists of a service plug-in and a set of drivers
that manage trunks on different layer-2 mechanism drivers. Users can
create a port, associate it with a trunk, and launch an instance on that
port. Users can dynamically attach and detach additional networks
without disrupting operation of the instance.

Every trunk has a parent port and can have any number of subports.
The parent port is the port that the trunk is associated with. Users
create instances and specify the parent port of the trunk when launching
instances attached to a trunk.

The network presented by the subport is the network of the associated
port. When creating a subport, a segmentation-id may be
required by the driver. segmentation-id defines the
segmentation ID on which the subport network is presented to the
instance. segmentation-type may be required by certain
drivers like OVS. At this time the following
segmentation-type values are supported:

  • vlan uses VLAN for segmentation.
  • inherit uses the segmentation-type from
    the network the subport is connected to if no
    segmentation-type is specified for the subport. Note that
    using the inherit type requires the provider
    extension to be enabled and only works when the connected network’s
    segmentation-type is vlan.

Note

The segmentation-type and segmentation-id
parameters are optional in the Networking API. However, all drivers as
of the Newton release require both to be provided when adding a subport
to a trunk. Future drivers may be implemented without this
requirement.

The segmentation-type and segmentation-id
specified by the user on the subports is intentionally decoupled from
the segmentation-type and ID of the networks. For example,
it is possible to configure the Networking service with
tenant_network_types = vxlan and still create subports with
segmentation_type = vlan. The Networking service performs
remapping as necessary.

Example configuration

The ML2 plug-in supports trunking with the following mechanism
drivers:

  • Open vSwitch (OVS)
  • Linux bridge
  • Open Virtual Network (OVN)

When using a segmentation-type of vlan, the
OVS and Linux bridge drivers present the network of the parent port as
the untagged VLAN and all subports as tagged VLANs.

Controller node

  • In the neutron.conf file, enable the trunk service
    plug-in:

    [DEFAULT]
    service_plugins = trunk

Verify service operation

  1. Source the administrative project credentials and list the enabled
    extensions.
  2. Use the command openstack extension list --network to verify that
    the Trunk Extension and Trunk port details
    extensions are enabled.

Workflow

At a high level, the basic steps to launching an instance on a trunk
are the following:

  1. Create networks and subnets for the trunk and subports
  2. Create the trunk
  3. Add subports to the trunk
  4. Launch an instance on the trunk

Create
networks and subnets for the trunk and subports

Create the appropriate networks for the trunk and subports that will
be added to the trunk. Create subnets on these networks to ensure the
desired layer-3 connectivity over the trunk.

Create the trunk

  • Create a parent port for the trunk.

    $ openstack port create --network project-net-A trunk-parent
    +-------------------+-------------------------------------------------------------------------+
    | Field             | Value                                                                   |
    +-------------------+-------------------------------------------------------------------------+
    | admin_state_up    | UP                                                                      |
    | binding_vif_type  | unbound                                                                 |
    | binding_vnic_type | normal                                                                  |
    | fixed_ips         | ip_address='192.0.2.7',subnet_id='8b957198-d3cf-4953-8449-ad4e4dd712cc' |
    | id                | 73fb9d54-43a7-4bb1-a8dc-569e0e0a0a38                                    |
    | mac_address       | fa:16:3e:dd:c4:d1                                                       |
    | name              | trunk-parent                                                            |
    | network_id        | 1b47d3e7-cda5-48e4-b0c8-d20bd7e35f55                                    |
    | revision_number   | 1                                                                       |
    | tags              | []                                                                      |
    +-------------------+-------------------------------------------------------------------------+
  • Create the trunk using --parent-port to reference
    the port from the previous step:

    $ openstack network trunk create --parent-port trunk-parent trunk1
    +-----------------+--------------------------------------+
    | Field           | Value                                |
    +-----------------+--------------------------------------+
    | admin_state_up  | UP                                   |
    | id              | fdf02fcb-1844-45f1-9d9b-e4c2f522c164 |
    | name            | trunk1                               |
    | port_id         | 73fb9d54-43a7-4bb1-a8dc-569e0e0a0a38 |
    | revision_number | 1                                    |
    | sub_ports       |                                      |
    +-----------------+--------------------------------------+

Add subports to the trunk

Subports can be added to a trunk in two ways: creating the trunk with
subports or adding subports to an existing trunk.

  • Create trunk with subports:

    This method entails creating the trunk with subports specified at
    trunk creation.

    $ openstack port create --network project-net-A trunk-parent
    +-------------------+-------------------------------------------------------------------------+
    | Field             | Value                                                                   |
    +-------------------+-------------------------------------------------------------------------+
    | admin_state_up    | UP                                                                      |
    | binding_vif_type  | unbound                                                                 |
    | binding_vnic_type | normal                                                                  |
    | fixed_ips         | ip_address='192.0.2.7',subnet_id='8b957198-d3cf-4953-8449-ad4e4dd712cc' |
    | id                | 73fb9d54-43a7-4bb1-a8dc-569e0e0a0a38                                    |
    | mac_address       | fa:16:3e:dd:c4:d1                                                       |
    | name              | trunk-parent                                                            |
    | network_id        | 1b47d3e7-cda5-48e4-b0c8-d20bd7e35f55                                    |
    | revision_number   | 1                                                                       |
    | tags              | []                                                                      |
    +-------------------+-------------------------------------------------------------------------+
    
    $ openstack port create --network trunked-net subport1
    +-------------------+----------------------------------------------------------------------------+
    | Field             | Value                                                                      |
    +-------------------+----------------------------------------------------------------------------+
    | admin_state_up    | UP                                                                         |
    | binding_vif_type  | unbound                                                                    |
    | binding_vnic_type | normal                                                                     |
    | fixed_ips         | ip_address='198.51.100.8',subnet_id='2a860e2c-922b-437b-a149-b269a8c9b120' |
    | id                | 91f9dde8-80a4-4506-b5da-c287feb8f5d8                                       |
    | mac_address       | fa:16:3e:ba:f0:4d                                                          |
    | name              | subport1                                                                   |
    | network_id        | aef78ec5-16e3-4445-b82d-b2b98c6a86d9                                       |
    | revision_number   | 1                                                                          |
    | tags              | []                                                                         |
    +-------------------+----------------------------------------------------------------------------+
    
    $ openstack network trunk create \
      --parent-port trunk-parent \
      --subport port=subport1,segmentation-type=vlan,segmentation-id=100 \
      trunk1
    +----------------+-------------------------------------------------------------------------------------------------+
    | Field          | Value                                                                                           |
    +----------------+-------------------------------------------------------------------------------------------------+
    | admin_state_up | UP                                                                                              |
    | id             | 61d8e620-fe3a-4d8f-b9e6-e1b0dea6d9e3                                                            |
    | name           | trunk1                                                                                          |
    | port_id        | 73fb9d54-43a7-4bb1-a8dc-569e0e0a0a38                                                            |
    | revision_number| 1                                                                                               |
    | sub_ports      | port_id='73fb9d54-43a7-4bb1-a8dc-569e0e0a0a38', segmentation_id='100', segmentation_type='vlan' |
    | tags           | []                                                                                              |
    +----------------+-------------------------------------------------------------------------------------------------+
  • Add subports to an existing trunk:

    This method entails creating a trunk, then adding subports to the
    trunk after it has already been created.

    $ openstack network trunk set --subport \
      port=subport1,segmentation-type=vlan,segmentation-id=100 \
      trunk1

    Note

    The command provides no output.

    $ openstack network trunk show trunk1
    +----------------+-------------------------------------------------------------------------------------------------+
    | Field          | Value                                                                                           |
    +----------------+-------------------------------------------------------------------------------------------------+
    | admin_state_up | UP                                                                                              |
    | id             | 61d8e620-fe3a-4d8f-b9e6-e1b0dea6d9e3                                                            |
    | name           | trunk1                                                                                          |
    | port_id        | 73fb9d54-43a7-4bb1-a8dc-569e0e0a0a38                                                            |
    | revision_number| 1                                                                                               |
    | sub_ports      | port_id='73fb9d54-43a7-4bb1-a8dc-569e0e0a0a38', segmentation_id='100', segmentation_type='vlan' |
    | tags           | []                                                                                              |
    +----------------+-------------------------------------------------------------------------------------------------+
  • When using the OVN driver, additional logical switch port
    information is available using the following commands:

    $ ovn-nbctl lsp-get-parent 61d8e620-fe3a-4d8f-b9e6-e1b0dea6d9e3
    73fb9d54-43a7-4bb1-a8dc-569e0e0a0a38
    
    $ ovn-nbctl lsp-get-tag 61d8e620-fe3a-4d8f-b9e6-e1b0dea6d9e3

Launch an instance on the
trunk

  • Show trunk details to get the port_id of the
    trunk.

    $ openstack network trunk show trunk1
    +----------------+--------------------------------------+
    | Field          | Value                                |
    +----------------+--------------------------------------+
    | admin_state_up | UP                                   |
    | id             | 61d8e620-fe3a-4d8f-b9e6-e1b0dea6d9e3 |
    | name           | trunk                                |
    | port_id        | 73fb9d54-43a7-4bb1-a8dc-569e0e0a0a38 |
    | revision_number| 1                                    |
    | sub_ports      |                                      |
    | tags           | []                                   |
    +----------------+--------------------------------------+
  • Launch the instance by specifying port-id using the
    value of port_id from the trunk details. Launching an
    instance on a subport is not supported.

Using trunks and
subports inside an instance

When configuring instances to use a subport, ensure that the
interface on the instance is set to use the MAC address assigned to the
port by the Networking service. Instances are not made aware of changes
made to the trunk after they are active. For example, when a subport
with a segmentation-type of vlan is added to a
trunk, any operations specific to the instance operating system that
allow the instance to send and receive traffic on the new VLAN must be
handled outside of the Networking service.

When creating subports, the MAC address of the trunk parent port can
be set on the subport. This will allow VLAN subinterfaces inside an
instance launched on a trunk to be configured without explicitly setting
a MAC address. Although unique MAC addresses can be used for subports,
this can present issues with ARP spoof protections and the native OVS
firewall driver. If the native OVS firewall driver is to be used, we
recommend that the MAC address of the parent port be re-used on all
subports.

Trunk states

  • ACTIVE

    The trunk is ACTIVE when both the logical and physical
    resources have been created. This means that all operations within the
    Networking and Compute services have completed and the trunk is ready
    for use.

  • DOWN

    A trunk is DOWN when it is first created without an
    instance launched on it, or when the instance associated with the trunk
    has been deleted.

  • DEGRADED

    A trunk can be in a DEGRADED state when a temporary
    failure during the provisioning process is encountered. This includes
    situations where a subport add or remove operation fails. When in a
    degraded state, the trunk is still usable and some subports may be
    usable as well. Operations that cause the trunk to go into a
    DEGRADED state can be retried to fix temporary failures and
    move the trunk into an ACTIVE state.

  • ERROR

    A trunk is in ERROR state if the request leads to a
    conflict or an error that cannot be fixed by retrying the request. The
    ERROR status can be encountered if the network is not
    compatible with the trunk configuration or the binding process leads to
    a persistent failure. When a trunk is in ERROR state, it
    must be brought to a sane state (ACTIVE), or else requests
    to add subports will be rejected.

  • BUILD

    A trunk is in BUILD state while the resources associated
    with the trunk are in the process of being provisioned. Once the trunk
    and all of the subports have been provisioned successfully, the trunk
    transitions to ACTIVE. If there was a partial failure, the
    trunk transitions to DEGRADED.

    When admin_state is set to DOWN, the user
    is blocked from performing operations on the trunk.
    admin_state is set by the user and should not be used to
    monitor the health of the trunk.

Limitations and issues

  • In neutron-ovs-agent the use of
    iptables_hybrid firewall driver and trunk ports are not
    compatible with each other. The iptables_hybrid firewall is
    not going to filter the traffic of subports. Instead use other firewall
    drivers like openvswitch.
  • See bugs
    for more information.

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