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_proxyservice to theservice_pluginssetting in the[DEFAULT]section of/etc/neutron/neutron.conf. For example:[DEFAULT] service_plugins = router,ndp_proxy
Note
The
routerservice plug-in has to be configured along with thendp_proxyservice plug-in.On the network nodes or the compute nodes (for the dvr mode router):
Set the
extensionsoption in the[agent]section of/etc/neutron/l3_agent.inito includendp_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-gwis 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.
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 | +------------+--------------------------------------+
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 | +-------------------+--------------------------------------+
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 | +---------------------------+--------------------------------------+
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 | +----------------------+--------------------------------------+
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_gatewayis configured on theneutron-l3-agent, you may want to setuse_lla_addressto 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 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
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: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 | +-----------------+--------------------------------------+
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.
