Chapter 11. VLAN-aware instances

11.1. VLAN trunks and VLAN transparent networks

VM instances can send and receive VLAN-tagged traffic over a single virtual NIC. This is particularly useful for NFV applications (VNFs) that expect VLAN-tagged traffic, allowing a single virtual NIC to serve multiple customers or services.

In ML2/OVN deployments you can support VLAN-aware instances using VLAN transparent networks. As an alternative in ML2/OVN or ML2/OVS deployments, you can support VLAN-aware instances using trunks.

In a VLAN transparent network, you set up VLAN tagging in the VM instances. The VLAN tags are transferred over the network and consumed by the instances on the same VLAN, and ignored by other instances and devices. In a VLAN transparent network, the VLANs are managed in the instance. You do not need to set up the VLAN in the OpenStack Networking Service (neutron).

VLAN trunks support VLAN-aware instances by combining VLANs into a single trunked port. For example, a project data network can use VLANs or tunneling (VXLAN, GRE, or Geneve) segmentation, while the instances see the traffic tagged with VLAN IDs. Network packets are tagged immediately before they are injected to the instance and do not need to be tagged throughout the entire network.

The following table compares certain features of VLAN transparent networks and VLAN trunks.

 TransparentTrunk

Mechanism driver support

ML2/OVN

ML2/OVN, ML2/OVS

VLAN setup managed by

VM instance

OpenStack Networking Service (neutron)

IP assignment

Configured in VM instance

Assigned by DHCP

VLAN ID

Flexible. You can set the VLAN ID in the instance

Fixed. Instances must use the VLAN ID configured in the trunk

11.2. Enabling VLAN transparency in ML2/OVN deployments

Enable VLAN transparency if you need to send VLAN tagged traffic between virtual machine (VM) instances. In a VLAN transparent network you can configure the VLANS directly in the VMs without configuring them in neutron.

Prerequisites

  • Deployment of Red Hat OpenStack Platform 16.1 or higher, with ML2/OVN as the mechanism driver.
  • Provider network of type VLAN or Geneve. Do not use VLAN transparency in deployments with flat type provider networks.
  • Ensure that the external switch supports 802.1q VLAN stacking using ethertype 0x8100 on both VLANs. OVN VLAN transparency does not support 802.1ad QinQ with outer provider VLAN ethertype set to 0x88A8 or 0x9100.

Procedure

  1. In an environment file on the undercloud node, set the EnableVLANTransparency parameter to true. For example, add the following lines to ovn-extras.yaml. 

    parameter_defaults:
    EnableVLANTransparency: true

  2. Include the environment file in the openstack overcloud deploy command with any other environment files that are relevant to your environment and deploy the overcloud: 

    $ openstack overcloud deploy \
--templates \
…
-e <other_overcloud_environment_files> \

-e ovn-extras.yaml \
…

    Replace <other_overcloud_environment_files> with the list of environment files that are part of your existing deployment.

  3. Create the network using the --transparent-vlan argument.

    Example

    $ openstack network create network-name --transparent-vlan

  4. Set up a VLAN interface on each participating VM.

    Set the interface MTU to 4 bytes less than the MTU of the underlay network to accommodate the extra tagging required by VLAN transparency. For example, if the underlay network MTU is 1500, set the interface MTU to 1496.

    The following example command adds a VLAN interface on eth0 with an MTU of 1496. The VLAN is 50 and the interface name is vlan50:

    Example

    $ ip link add link eth0 name vlan50 type vlan id 50 mtu 1496
$ ip link set vlan50 up
$ ip addr add 192.128.111.3/24 dev vlan50

  5. Set --allowed-address on the VM port.

    Set the allowed address to the IP address you created on the VLAN interface inside the VM in step 4. Optionally, you can also set the VLAN interface MAC address:

    Example

    The following example sets the IP address to 192.128.111.3 with the optional MAC address 00:40:96:a8:45:c4 on port fv82gwk3-qq2e-yu93-go31-56w7sf476mm0: 

    $ openstack port set --allowed-address ip-address=192.128.111.3,mac-address=00:40:96:a8:45:c4 fv82gwk3-qq2e-yu93-go31-56w7sf476mm0

Verification

  1. Ping between two VMs on the VLAN using the vlan50 IP address.
  2. Use tcpdump on eth0 to see if the packets arrive with the VLAN tag intact.

Additional resources

11.3. Reviewing the trunk plug-in

During a Red Hat openStack deployment, the trunk plug-in is enabled by default. You can review the configuration on the controller nodes:

  • On the controller node, confirm that the trunk plug-in is enabled in the /var/lib/config-data/puppet-generated/neutron/etc/neutron/neutron.conf file: 

    service_plugins=router,qos,trunk

11.4. Creating a trunk connection

To implement trunks for VLAN-tagged traffic, create a parent port and attach the new port to an existing neutron network. When you attach the new port, OpenStack Networking adds a trunk connection to the parent port you created. Next, create subports. These subports connect VLANs to instances, which allow connectivity to the trunk. Within the instance operating system, you must also create a sub-interface that tags traffic for the VLAN associated with the subport.

  1. Identify the network that contains the instances that require access to the trunked VLANs. In this example, this is the public network: 

    openstack network list
+--------------------------------------+---------+--------------------------------------+
| ID                                   | Name    | Subnets                              |
+--------------------------------------+---------+--------------------------------------+
| 82845092-4701-4004-add7-838837837621 | private | 434c7982-cd96-4c41-a8c9-b93adbdcb197 |
| 8d8bc6d6-5b28-4e00-b99e-157516ff0050 | public  | 3fd811b4-c104-44b5-8ff8-7a86af5e332c |
+--------------------------------------+---------+--------------------------------------+

  2. Create the parent trunk port, and attach it to the network that the instance connects to. In this example, create a neutron port named parent-trunk-port on the public network. This trunk is the parent port, as you can use it to create subports. 

    openstack port create --network public parent-trunk-port
+-----------------------+-----------------------------------------------------------------------------+
| Field                 | Value                                                                       |
+-----------------------+-----------------------------------------------------------------------------+
| admin_state_up        | UP                                                                          |
| allowed_address_pairs |                                                                             |
| binding_host_id       |                                                                             |
| binding_profile       |                                                                             |
| binding_vif_details   |                                                                             |
| binding_vif_type      | unbound                                                                     |
| binding_vnic_type     | normal                                                                      |
| created_at            | 2016-10-20T02:02:33Z                                                        |
| description           |                                                                             |
| device_id             |                                                                             |
| device_owner          |                                                                             |
| extra_dhcp_opts       |                                                                             |
| fixed_ips             | ip_address='172.24.4.230', subnet_id='dc608964-9af3-4fed-9f06-6d3844fb9b9b' |
| headers               |                                                                             |
| id                    | 20b6fdf8-0d43-475a-a0f1-ec8f757a4a39                                        |
| mac_address           | fa:16:3e:33:c4:75                                                           |
| name                  | parent-trunk-port                                                           |
| network_id            | 871a6bd8-4193-45d7-a300-dcb2420e7cc3                                        |
| project_id            | 745d33000ac74d30a77539f8920555e7                                            |
| project_id            | 745d33000ac74d30a77539f8920555e7                                            |
| revision_number       | 4                                                                           |
| security_groups       | 59e2af18-93c6-4201-861b-19a8a8b79b23                                        |
| status                | DOWN                                                                        |
| updated_at            | 2016-10-20T02:02:33Z                                                        |
+-----------------------+-----------------------------------------------------------------------------+

  3. Create a trunk using the port that you created in step 2. In this example the trunk is named parent-trunk. 

    openstack network trunk create --parent-port parent-trunk-port parent-trunk
+-----------------+--------------------------------------+
| Field           | Value                                |
+-----------------+--------------------------------------+
| admin_state_up  | UP                                   |
| created_at      | 2016-10-20T02:05:17Z                 |
| description     |                                      |
| id              | 0e4263e2-5761-4cf6-ab6d-b22884a0fa88 |
| name            | parent-trunk                         |
| port_id         | 20b6fdf8-0d43-475a-a0f1-ec8f757a4a39 |
| revision_number | 1                                    |
| status          | DOWN                                 |
| sub_ports       |                                      |
| tenant_id       | 745d33000ac74d30a77539f8920555e7     |
| updated_at      | 2016-10-20T02:05:17Z                 |
+-----------------+--------------------------------------+

  4. View the trunk connection: 

    openstack network trunk list
+--------------------------------------+--------------+--------------------------------------+-------------+
| ID                                   | Name         | Parent Port                          | Description |
+--------------------------------------+--------------+--------------------------------------+-------------+
| 0e4263e2-5761-4cf6-ab6d-b22884a0fa88 | parent-trunk | 20b6fdf8-0d43-475a-a0f1-ec8f757a4a39 |             |
+--------------------------------------+--------------+--------------------------------------+-------------+

  5. View the details of the trunk connection: 

    openstack network trunk show parent-trunk
+-----------------+--------------------------------------+
| Field           | Value                                |
+-----------------+--------------------------------------+
| admin_state_up  | UP                                   |
| created_at      | 2016-10-20T02:05:17Z                 |
| description     |                                      |
| id              | 0e4263e2-5761-4cf6-ab6d-b22884a0fa88 |
| name            | parent-trunk                         |
| port_id         | 20b6fdf8-0d43-475a-a0f1-ec8f757a4a39 |
| revision_number | 1                                    |
| status          | DOWN                                 |
| sub_ports       |                                      |
| tenant_id       | 745d33000ac74d30a77539f8920555e7     |
| updated_at      | 2016-10-20T02:05:17Z                 |
+-----------------+--------------------------------------+

11.5. Adding subports to the trunk

  1. Create a neutron port.

    This port is a subport connection to the trunk. You must also specify the MAC address that you assigned to the parent port: 

    openstack port create --network private --mac-address fa:16:3e:33:c4:75 subport-trunk-port
+-----------------------+--------------------------------------------------------------------------+
| Field                 | Value                                                                    |
+-----------------------+--------------------------------------------------------------------------+
| admin_state_up        | UP                                                                       |
| allowed_address_pairs |                                                                          |
| binding_host_id       |                                                                          |
| binding_profile       |                                                                          |
| binding_vif_details   |                                                                          |
| binding_vif_type      | unbound                                                                  |
| binding_vnic_type     | normal                                                                   |
| created_at            | 2016-10-20T02:08:14Z                                                     |
| description           |                                                                          |
| device_id             |                                                                          |
| device_owner          |                                                                          |
| extra_dhcp_opts       |                                                                          |
| fixed_ips             | ip_address='10.0.0.11', subnet_id='1a299780-56df-4c0b-a4c0-c5a612cef2e8' |
| headers               |                                                                          |
| id                    | 479d742e-dd00-4c24-8dd6-b7297fab3ee9                                     |
| mac_address           | fa:16:3e:33:c4:75                                                        |
| name                  | subport-trunk-port                                                       |
| network_id            | 3fe6b758-8613-4b17-901e-9ba30a7c4b51                                     |
| project_id            | 745d33000ac74d30a77539f8920555e7                                         |
| project_id            | 745d33000ac74d30a77539f8920555e7                                         |
| revision_number       | 4                                                                        |
| security_groups       | 59e2af18-93c6-4201-861b-19a8a8b79b23                                     |
| status                | DOWN                                                                     |
| updated_at            | 2016-10-20T02:08:15Z                                                     |
+-----------------------+--------------------------------------------------------------------------+
    Note

    If you receive the error HttpException: Conflict, confirm that you are creating the subport on a different network to the one that has the parent trunk port. This example uses the public network for the parent trunk port, and private for the subport.

  2. Associate the port with the trunk (parent-trunk), and specify the VLAN ID (55): 

    openstack network trunk set --subport port=subport-trunk-port,segmentation-type=vlan,segmentation-id=55 parent-trunk

11.6. Configuring an instance to use a trunk

You must configure the VM instance operating system to use the MAC address that the Red Hat OpenStack Platform (RHOSP) Networking service (neutron) assigned to the subport. You can also configure the subport to use a specific MAC address during the subport creation step.

Prerequisites

  • If you are performing live migrations of your Compute nodes, ensure that the RHOSP Networking service RPC response timeout is appropriately set for your RHOSP deployment. The RPC response timeout value can vary between sites and is dependent on the system speed. The general recommendation is to set the value to at least 120 seconds per/100 trunk ports.

    The best practice is to measure the trunk port bind process time for your RHOSP deployment, and then set the RHOSP Networking service RPC response timeout appropriately. Try to keep the RPC response timeout value low, but also provide enough time for the RHOSP Networking service to receive an RPC response. For more information, see Section 11.7, “Configuring Networking service RPC timeout”.

Procedure

  1. Review the configuration of your network trunk, using the network trunk command.

    Example

    $ openstack network trunk list

    Sample output

    +---------------------+--------------+---------------------+-------------+
| ID                  | Name         | Parent Port         | Description |
+---------------------+--------------+---------------------+-------------+
| 0e4263e2-5761-4cf6- | parent-trunk | 20b6fdf8-0d43-475a- |             |
| ab6d-b22884a0fa88   |              | a0f1-ec8f757a4a39   |             |
+---------------------+--------------+---------------------+-------------+

    Example

    $ openstack network trunk show parent-trunk

    Sample output

    +-----------------+------------------------------------------------------+
| Field           | Value                                                |
+-----------------+------------------------------------------------------+
| admin_state_up  | UP                                                   |
| created_at      | 2021-10-20T02:05:17Z                                 |
| description     |                                                      |
| id              | 0e4263e2-5761-4cf6-ab6d-b22884a0fa88                 |
| name            | parent-trunk                                         |
| port_id         | 20b6fdf8-0d43-475a-a0f1-ec8f757a4a39                 |
| revision_number | 2                                                    |
| status          | DOWN                                                 |
| sub_ports       | port_id='479d742e-dd00-4c24-8dd6-b7297fab3ee9', segm |
|                 | entation_id='55', segmentation_type='vlan'           |
| tenant_id       | 745d33000ac74d30a77539f8920555e7                     |
| updated_at      | 2021-08-20T02:10:06Z                                 |
+-----------------+------------------------------------------------------+

  2. Create an instance that uses the parent port-id as its vNIC.

    Example

    openstack server create --image cirros --flavor m1.tiny --security-group default --key-name sshaccess --nic port-id=20b6fdf8-0d43-475a-a0f1-ec8f757a4a39 testInstance

    Sample output

    +--------------------------------------+---------------------------------+
| Property                             | Value                           |
+--------------------------------------+---------------------------------+
| OS-DCF:diskConfig                    | MANUAL                          |
| OS-EXT-AZ:availability_zone          |                                 |
| OS-EXT-SRV-ATTR:host                 | -                               |
| OS-EXT-SRV-ATTR:hostname             | testinstance                    |
| OS-EXT-SRV-ATTR:hypervisor_hostname  | -                               |
| OS-EXT-SRV-ATTR:instance_name        |                                 |
| OS-EXT-SRV-ATTR:kernel_id            |                                 |
| OS-EXT-SRV-ATTR:launch_index         | 0                               |
| OS-EXT-SRV-ATTR:ramdisk_id           |                                 |
| OS-EXT-SRV-ATTR:reservation_id       | r-juqco0el                      |
| OS-EXT-SRV-ATTR:root_device_name     | -                               |
| OS-EXT-SRV-ATTR:user_data            | -                               |
| OS-EXT-STS:power_state               | 0                               |
| OS-EXT-STS:task_state                | scheduling                      |
| OS-EXT-STS:vm_state                  | building                        |
| OS-SRV-USG:launched_at               | -                               |
| OS-SRV-USG:terminated_at             | -                               |
| accessIPv4                           |                                 |
| accessIPv6                           |                                 |
| adminPass                            | uMyL8PnZRBwQ                    |
| config_drive                         |                                 |
| created                              | 2021-08-20T03:02:51Z            |
| description                          | -                               |
| flavor                               | m1.tiny (1)                     |
| hostId                               |                                 |
| host_status                          |                                 |
| id                                   | 88b7aede-1305-4d91-a180-67e7eac |
|                                      | 8b70d                           |
| image                                | cirros (568372f7-15df-4e61-a05f |
|                                      | -10954f79a3c4)                  |
| key_name                             | sshaccess                       |
| locked                               | False                           |
| metadata                             | {}                              |
| name                                 | testInstance                    |
| os-extended-volumes:volumes_attached | []                              |
| progress                             | 0                               |
| security_groups                      | default                         |
| status                               | BUILD                           |
| tags                                 | []                              |
| tenant_id                            | 745d33000ac74d30a77539f8920555e |
|                                      | 7                               |
| updated                              | 2021-08-20T03:02:51Z            |
| user_id                              | 8c4aea738d774967b4ef388eb41fef5 |
|                                      | e                               |
+--------------------------------------+---------------------------------+

Additional resources

11.7. Configuring Networking service RPC timeout

There can be situations when you must modify the Red Hat OpenStack Platform (RHOSP) Networking service (neutron) RPC response timeout. For example, live migrations for Compute nodes that use trunk ports can fail if the timeout value is too low.

The RPC response timeout value can vary between sites and is dependent on the system speed. The general recommendation is to set the value to at least 120 seconds per/100 trunk ports.

If your site uses trunk ports, the best practice is to measure the trunk port bind process time for your RHOSP deployment, and then set the RHOSP Networking service RPC response timeout appropriately. Try to keep the RPC response timeout value low, but also provide enough time for the RHOSP Networking service to receive an RPC response.

By using a manual hieradata override, rpc_response_timeout, you can set the RPC response timeout value for the RHOSP Networking service.

Procedure

  1. On the undercloud host, logged in as the stack user, create a custom YAML environment file.

    Example

    $ vi /home/stack/templates/my-modules-environment.yaml

    Tip

    The RHOSP Orchestration service (heat) uses a set of plans called templates to install and configure your environment. You can customize aspects of the overcloud with a custom environment file, which is a special type of template that provides customization for your heat templates.

  2. In the YAML environment file under ExtraConfig, set the appropriate value (in seconds) for rpc_response_timeout. (The default value is 60 seconds.)

    Example

    parameter_defaults:
  ExtraConfig:
    neutron::rpc_response_timeout: 120

    Note

    The RHOSP Orchestration service (heat) updates all RHOSP nodes with the value you set in the custom environment file, however this value only impacts the RHOSP Networking components.

  3. Run the openstack overcloud deploy command and include the core heat templates, environment files, and this new custom environment file.

    Important

    The order of the environment files is important as the parameters and resources defined in subsequent environment files take precedence.

    Example

    $ openstack overcloud deploy --templates \
-e [your-environment-files] \
-e /usr/share/openstack-tripleo-heat-templates/environments/services/my-modules-environment.yaml

Additional resources

11.8. Understanding trunk states

  • ACTIVE: The trunk is working as expected and there are no current requests.
  • DOWN: The virtual and physical resources for the trunk are not in sync. This can be a temporary state during negotiation.
  • BUILD: There has been a request and the resources are being provisioned. After successful completion the trunk returns to ACTIVE.
  • DEGRADED: The provisioning request did not complete, so the trunk has only been partially provisioned. It is recommended to remove the subports and try again.
  • ERROR: The provisioning request was unsuccessful. Remove the resource that caused the error to return the trunk to a healthier state. Do not add more subports while in the ERROR state, as this can cause more issues.