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Taikun OCP Guide

Table of Contents

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 the [DEFAULT]
    section of /etc/neutron/neutron.conf. For example:

    [DEFAULT]
    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 the 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 to install this command manually in every L3
agent node. For Ubuntu, the command is provided by the
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:db8::/96. The
    direct route like below should be set:

    2001:db8::/96 dev <ext-gw>

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

User workflow

The basic steps to publish an IPv6 address to an external network
(such as: public network) are the following:

Note

In order to prevent a potential security
risk
, the NDP proxy feature requires that an IPv6 address scope be
used to ensure the uniqueness of the IPv6 address which is published
externally.

  1. Create an IPv6 address scope

    $ openstack address scope create test-ipv6-as --ip-version 6
    +------------+--------------------------------------+
    | Field      | Value                                |
    +------------+--------------------------------------+
    | id         | 24761ec5-b659-4358-b9ab-495ead15fa7a |
    | ip_version | 6                                    |
    | name       | test-ipv6-as                         |
    | project_id | bcb0c7a5338b4a46959e47971c58f0f1     |
    | shared     | False                                |
    +------------+--------------------------------------+
  2. Create an IPv6 subnet pool

    $ openstack subnet pool create test-subnetpool --address-scope test-ipv6-as \
            --pool-prefix 2001:db8::/96 --default-prefix-length 112
    +-------------------+--------------------------------------+
    | Field             | Value                                |
    +-------------------+--------------------------------------+
    | address_scope_id  | 24761ec5-b659-4358-b9ab-495ead15fa7a |
    | created_at        | 2022-09-05T06:16:31Z                 |
    | default_prefixlen | 112                                  |
    | default_quota     | None                                 |
    | description       |                                      |
    | id                | 4af07f59-45b8-424d-98c5-35d20ba61526 |
    | ip_version        | 6                                    |
    | is_default        | False                                |
    | max_prefixlen     | 128                                  |
    | min_prefixlen     | 64                                   |
    | name              | test-subnetpool                      |
    | prefixes          | 2001:db8::/96                        |
    | project_id        | bcb0c7a5338b4a46959e47971c58f0f1     |
    | revision_number   | 0                                    |
    | shared            | False                                |
    | tags              |                                      |
    | updated_at        | 2022-01-01T06:42:08Z                 |
    +-------------------+--------------------------------------+
  3. Create an external network

    $ openstack network create --external --provider-network-type flat \
          --provider-physical-network public public
    +---------------------------+--------------------------------------+
    | Field                     | Value                                |
    +---------------------------+--------------------------------------+
    | admin_state_up            | UP                                   |
    | availability_zone_hints   |                                      |
    | availability_zones        |                                      |
    | created_at                | 2022-09-05T06:18:31Z                 |
    | description               |                                      |
    | dns_domain                | None                                 |
    | id                        | 98b0f468-7be0-4530-919d-c4d9417c3abf |
    | ipv4_address_scope        | None                                 |
    | ipv6_address_scope        | None                                 |
    | is_default                | False                                |
    | is_vlan_transparent       | None                                 |
    | mtu                       | 1500                                 |
    | name                      | public                               |
    | port_security_enabled     | True                                 |
    | project_id                | bcb0c7a5338b4a46959e47971c58f0f1     |
    | provider:network_type     | flat                                 |
    | provider:physical_network | public                               |
    | provider:segmentation_id  | None                                 |
    | qos_policy_id             | None                                 |
    | revision_number           | 1                                    |
    | router:external           | External                             |
    | segments                  | None                                 |
    | shared                    | False                                |
    | status                    | ACTIVE                               |
    | subnets                   |                                      |
    | tags                      |                                      |
    | updated_at                | 2022-01-01T06:45:08Z                 |
    +---------------------------+--------------------------------------+
  4. Create an external subnet

    $ openstack subnet create --network public --subnet-pool test-subnetpool \
            --prefix-length 112 --ip-version 6 --no-dhcp ext-sub
     +----------------------+--------------------------------------+
    | Field                | Value                                |
    +----------------------+--------------------------------------+
    | allocation_pools     | 2001:db8::2-2001:db8::ffff           |
    | cidr                 | 2001:db8::/112                       |
    | created_at           | 2022-09-05T06:21:37Z                 |
    | description          |                                      |
    | dns_nameservers      |                                      |
    | dns_publish_fixed_ip | None                                 |
    | enable_dhcp          | False                                |
    | gateway_ip           | 2001:db8::1                          |
    | host_routes          |                                      |
    | id                   | ec11de28-9b84-4cee-b6a1-0ed56135bcd8 |
    | ip_version           | 6                                    |
    | ipv6_address_mode    | None                                 |
    | ipv6_ra_mode         | None                                 |
    | name                 | ext-sub                              |
    | network_id           | 98b0f468-7be0-4530-919d-c4d9417c3abf |
    | project_id           | bcb0c7a5338b4a46959e47971c58f0f1     |
    | revision_number      | 0                                    |
    | segment_id           | None                                 |
    | service_types        |                                      |
    | subnetpool_id        | 4af07f59-45b8-424d-98c5-35d20ba61526 |
    | tags                 |                                      |
    | updated_at           | 2022-01-01T06:47:08Z                 |
    +----------------------+--------------------------------------+
  5. 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                 |
    +-------------------------+--------------------------------------+
  6. 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.

  7. 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 <config-bgp-dynamic-routing-for-ipv6>, prefix-delegation etc.) to
    publish the internal IPv6 address, the command will break dataplane
    traffic.

  8. Create an internal network and IPv6 subnet and add the subnet to
    the 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:db8::1:2-2001:db8::1:ffff       |
    | cidr                 | 2001:db8::1:0/112                    |
    | created_at           | 2022-09-05T06:24:13Z                 |
    | description          |                                      |
    | dns_nameservers      |                                      |
    | dns_publish_fixed_ip | None                                 |
    | enable_dhcp          | True                                 |
    | gateway_ip           | 2001:db8::1:1                        |
    | 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        | 4af07f59-45b8-424d-98c5-35d20ba61526 |
    | tags                 |                                      |
    | updated_at           | 2022-01-02T08:20:26Z                 |
    +----------------------+--------------------------------------+
    $ openstack router add subnet test-router int-sub
  9. 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                    |                                                                 |
    +-------------------------------------+-----------------------------------------------------------------+
  10. 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:db8::1:284', subnet_id='9bcf194c-d44f-4e6f-90da-98510ddef283' | ACTIVE |
    +--------------------------------------+------+-------------------+--------------------------------------------------------------------------------+--------+

    Create NDP proxy for the port

    $ openstack router ndp proxy create test-router --port bdd64aa0-437a-4db6-bbca-99869426c908 --name test-np
    +-----------------+--------------------------------------+
    | Field           | Value                                |
    +-----------------+--------------------------------------+
    | created_at      | 2022-01-02T08:25:31Z                 |
    | description     |                                      |
    | id              | 73889fee-e322-443f-941e-142e4fc5f898 |
    | ip_address      | 2001:db8::1:284                      |
    | 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                 |
    +-----------------+--------------------------------------+
  11. Then ping the port’s address from the upstream router:

    $ ping 2001:db8::1:284
    PING 2001:db8::1:284(2001:db8::1:284) 56 data bytes
    64 bytes from 2001:db8::1:284: icmp_seq=1 ttl=64 time=0.365 ms
    64 bytes from 2001:db8::1:284: icmp_seq=2 ttl=64 time=0.385 ms

    Note

    You may also need to add a security group rule that allows ICMPv6
    traffic towards the instance.

Known limitations

  • Using NDP proxies in combination with the OVN backend is not
    supported.

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