NDP proxy

If NDP proxy is set on a router, it is used to publish IPv6 addresses to external routers. Its purpose is similar to floating IP, but it forwards the traffic directly by using route rules and has no NAT action. Read the related specification for more details.

Configuration of NDP proxy

To configure NDP proxy, take the following steps:

  • On the controller nodes:

    Add the ndp_proxy service to the service_plugins setting in /etc/neutron/neutron.conf. For example:

    service_plugins = router,ndp_proxy
    

    Note

    The router service plug-in has to be configured along with the ndp_proxy service plug-in

  • On the network nodes or the compute nodes (for the dvr mode router):

    Set the extensions option in the [agent] section of /etc/neutron/l3_agent.ini to include ndp_proxy. This has to be done in each network and compute node where the L3 agent is running. For example:

    extensions = ndp_proxy
    

Note

After updating the options in the configuration files, the neutron-server and every neutron-l3-agent need to be restarted for the new values to take effect.

After configuring ndp proxy, the ndp-proxy extension alias will be included in the output of the following command:

For api extension:

$ openstack extension list --network

For agent extension:

$ openstack network agent show <l3-agent-id>

Note

We Introduced a new command ndsend for NDP proxy feature, the command can send Neighbor Advertisement about IPv6 to upstream router. With this command, we can make the upstream router rapidly perceive the change of internal IPv6 address (such as, port migrated to other node). Read the manual page for more details about this command.

Currently, you need install this command manually in every l3 agent node. For ubuntu, the command provided by vzctl pkg, the install command: sudo apt install vzctl.

  • On the upstream router (The datacenter’s physical router):

    Generally, the admin operator should plan one or more IPv6 subnetpools to use when NDP proxy is enabled, so that all internal subnets can be allocated from a single, integrated subnetpool. In order to make NDP proxy work correctly, the admin operator needs to set direct routes for these subnetpools.

    Such as, we have a IPv6 subnetpool, it’s CIDR is 2001::/96. The direct route like below should be set:

    2001::/96 dev <ext-gw>
    

    The ext-gw is the gateway interface of the cloud’s external network.

User workflow

Assume the admin operator already prepared an IPv6 subnetpool: test-subnetpool, its CIDR is 2001::/96.

At a high level, the basic steps to publish an IPv6 address to external network (such as: public network) are the following:

1、Create a router and enable its external gateway 2、Set the router’s enable_ndp_proxy parameter to True 3、Create a internal network and create a IPv6 subnet on it 4、Add the subnet to the router 5、Launch an instance on the network 6、Create a ndp proxy for the instance’s port

  • Create a router:

    $ openstack router create test-router
    +-------------------------+--------------------------------------+
    | Field                   | Value                                |
    +-------------------------+--------------------------------------+
    | admin_state_up          | UP                                   |
    | availability_zone_hints |                                      |
    | availability_zones      |                                      |
    | created_at              | 2022-01-01T06:50:44Z                 |
    | description             |                                      |
    | distributed             | False                                |
    | enable_ndp_proxy        | False                                |
    | external_gateway_info   | null                                 |
    | flavor_id               | None                                 |
    | ha                      | False                                |
    | id                      | 3aab8554-e5c4-4262-ab95-b92857c641de |
    | name                    | test-router                          |
    | project_id              | bcb0c7a5338b4a46959e47971c58f0f1     |
    | revision_number         | 1                                    |
    | routes                  |                                      |
    | status                  | ACTIVE                               |
    | tags                    |                                      |
    | updated_at              | 2022-01-01T06:50:44Z                 |
    +-------------------------+--------------------------------------+
    
  • Set external gateway for the router:

    $ openstack router set test-router --external-gateway public
    

    Note

    If the external network has no IPv6 subnet and the ipv6_gateway is configured on the neutron-l3-agent, you may want to set use_lla_address to True at /etc/neutron/neutron.conf, otherwise The following command will raise a 403 error.

  • Enable ndp proxy support on the router:

    $ openstack router set test-router --enable-ndp-proxy
    

    Warning

    If you are using another method (such as: BGP, Prefix delegation etc.) to publish the internal IPv6 address, the command will break dataplane traffic.

  • Create internal network and IPv6 subnet and add the subnet to above router:

    $ openstack network create int-net
    +---------------------------+--------------------------------------+
    | Field                     | Value                                |
    +---------------------------+--------------------------------------+
    | admin_state_up            | UP                                   |
    | availability_zone_hints   |                                      |
    | availability_zones        |                                      |
    | created_at                | 2022-01-01T07:11:08Z                 |
    | description               |                                      |
    | dns_domain                | None                                 |
    | id                        | e527b38e-9e2a-439b-adf8-4ee1aa4f03b1 |
    | ipv4_address_scope        | None                                 |
    | ipv6_address_scope        | None                                 |
    | is_default                | False                                |
    | is_vlan_transparent       | None                                 |
    | mtu                       | 1450                                 |
    | name                      | int-net                              |
    | port_security_enabled     | True                                 |
    | project_id                | bcb0c7a5338b4a46959e47971c58f0f1     |
    | provider:network_type     | vxlan                                |
    | provider:physical_network | None                                 |
    | provider:segmentation_id  | 575                                  |
    | qos_policy_id             | None                                 |
    | revision_number           | 1                                    |
    | router:external           | Internal                             |
    | segments                  | None                                 |
    | shared                    | False                                |
    | status                    | ACTIVE                               |
    | subnets                   |                                      |
    | tags                      |                                      |
    | updated_at                | 2022-01-01T07:11:08Z                 |
    +---------------------------+--------------------------------------+
    $ openstack subnet create --network int-net --subnet-pool test-subnetpool \
      --prefix-length 112 --ip-version 6 \
      --ipv6-ra-mode dhcpv6-stateful \
      --ipv6-address-mode dhcpv6-stateful int-sub
    +----------------------+--------------------------------------+
    | Field                | Value                                |
    +----------------------+--------------------------------------+
    | allocation_pools     | 2001::2-2001::ffff                   |
    | cidr                 | 2001::/112                           |
    | created_at           | 2022-01-02T08:20:26Z                 |
    | description          |                                      |
    | dns_nameservers      |                                      |
    | dns_publish_fixed_ip | None                                 |
    | enable_dhcp          | True                                 |
    | gateway_ip           | 2001::1                              |
    | host_routes          |                                      |
    | id                   | 9bcf194c-d44f-4e6f-90da-98510ddef283 |
    | ip_version           | 6                                    |
    | ipv6_address_mode    | dhcpv6-stateful                      |
    | ipv6_ra_mode         | dhcpv6-stateful                      |
    | name                 | int-sub                              |
    | network_id           | e527b38e-9e2a-439b-adf8-4ee1aa4f03b1 |
    | project_id           | bcb0c7a5338b4a46959e47971c58f0f1     |
    | revision_number      | 0                                    |
    | segment_id           | None                                 |
    | service_types        |                                      |
    | subnetpool_id        | 73c5311c-6750-43f5-9a69-b50c1c5694fd |
    | tags                 |                                      |
    | updated_at           | 2022-01-02T08:20:26Z                 |
    +----------------------+--------------------------------------+
    $ openstack router add subnet test-router int-sub
    
  • Launch an instance:

    $ openstack server create --flavor m1.tiny --image cirros-0.5.2-x86_64-disk --network int-net test-server
    +-------------------------------------+-----------------------------------------------------------------+
    | Field                               | Value                                                           |
    +-------------------------------------+-----------------------------------------------------------------+
    | OS-DCF:diskConfig                   | MANUAL                                                          |
    | OS-EXT-AZ:availability_zone         |                                                                 |
    | OS-EXT-SRV-ATTR:host                | None                                                            |
    | OS-EXT-SRV-ATTR:hypervisor_hostname | None                                                            |
    | OS-EXT-SRV-ATTR:instance_name       |                                                                 |
    | OS-EXT-STS:power_state              | NOSTATE                                                         |
    | OS-EXT-STS:task_state               | scheduling                                                      |
    | OS-EXT-STS:vm_state                 | building                                                        |
    | OS-SRV-USG:launched_at              | None                                                            |
    | OS-SRV-USG:terminated_at            | None                                                            |
    | accessIPv4                          |                                                                 |
    | accessIPv6                          |                                                                 |
    | addresses                           |                                                                 |
    | adminPass                           | 97UvRLgdFozR                                                    |
    | config_drive                        |                                                                 |
    | created                             | 2022-01-02T08:22:35Z                                            |
    | flavor                              | m1.tiny (1)                                                     |
    | hostId                              |                                                                 |
    | id                                  | 189a104c-36cd-479a-8702-8111eb34fdb6                            |
    | image                               | cirros-0.5.2-x86_64-disk (2b2d2975-7ffc-463b-8c0e-993122f38b77) |
    | key_name                            | None                                                            |
    | name                                | test-server                                                     |
    | progress                            | 0                                                               |
    | project_id                          | bcb0c7a5338b4a46959e47971c58f0f1                                |
    | properties                          |                                                                 |
    | security_groups                     | name='default'                                                  |
    | status                              | BUILD                                                           |
    | updated                             | 2022-01-02T08:22:34Z                                            |
    | user_id                             | 27e0947bb4fe47e4981da31d4a18ddf7                                |
    | volumes_attached                    |                                                                 |
    +-------------------------------------+-----------------------------------------------------------------+
    
  • Create ndp proxy for the instance’s port:

    Query the port of the instance

    $ openstack port list --server test-server
    +--------------------------------------+------+-------------------+--------------------------------------------------------------------------+--------+
    | ID                                   | Name | MAC Address       | Fixed IP Addresses                                                       | Status |
    +--------------------------------------+------+-------------------+--------------------------------------------------------------------------+--------+
    | bdd64aa0-437a-4db6-bbca-99869426c908 |      | fa:16:3e:ac:15:b8 | ip_address='2001::284', subnet_id='9bcf194c-d44f-4e6f-90da-98510ddef283' | ACTIVE |
    +--------------------------------------+------+-------------------+--------------------------------------------------------------------------+--------+
    

    Create ndp proxy for the port

    $ openstack network ndp proxy create --router test-router --port bdd64aa0-437a-4db6-bbca-99869426c908 test-np
    +-----------------+--------------------------------------+
    | Field           | Value                                |
    +-----------------+--------------------------------------+
    | created_at      | 2022-01-02T08:25:31Z                 |
    | description     |                                      |
    | id              | 73889fee-e322-443f-941e-142e4fc5f898 |
    | ip_address      | 2001::284                            |
    | name            | test-np                              |
    | port_id         | bdd64aa0-437a-4db6-bbca-99869426c908 |
    | project_id      | bcb0c7a5338b4a46959e47971c58f0f1     |
    | revision_number | 0                                    |
    | router_id       | 3aab8554-e5c4-4262-ab95-b92857c641de |
    | updated_at      | 2022-01-02T08:25:31Z                 |
    +-----------------+--------------------------------------+
    
  • Then ping the port’s address from upstream router

    $ ping 2001::284
    PING 2001::284(2001::284) 56 data bytes
    64 bytes from 2001::284: icmp_seq=1 ttl=64 time=0.365 ms
    64 bytes from 2001::284: icmp_seq=2 ttl=64 time=0.385 ms
    

Known limitations

  • OVN backend is not supported