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.
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
.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.
The ML2 plug-in supports trunking with the following mechanism drivers:
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.
In the neutron.conf
file, enable the trunk service plug-in:
[DEFAULT]
service_plugins = trunk
Trunk Extension
and Trunk port details
extensions are
enabled.At a high level, the basic steps to launching an instance on a trunk are the following:
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 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 | |
+-----------------+--------------------------------------+
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
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 | [] |
+----------------+-------------------------------------------------------------------------------------------------+
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.
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.
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.
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