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Merge "[ovn]: port forwarding -- documentation"

changes/35/744035/1
Zuul 4 days ago
committed by Gerrit Code Review
parent
commit
17324fe1cf
4 changed files with 127 additions and 35 deletions
  1. +10
    -2
      doc/source/admin/ovn/features.rst
  2. +11
    -33
      doc/source/ovn/gaps.rst
  3. +1
    -0
      doc/source/ovn/index.rst
  4. +105
    -0
      doc/source/ovn/port_forwarding.rst

+ 10
- 2
doc/source/admin/ovn/features.rst View File

@@ -25,7 +25,7 @@ services:

* DPDK

OVN and ovn mechanism driver may be used with OVS using either the Linux
OVN and the OVN mechanism driver may be used with OVS using either the Linux
kernel datapath or the DPDK datapath.

* Trunk driver
@@ -36,7 +36,7 @@ services:

* VLAN tenant networks

The ovn driver does support VLAN tenant networks when used
The OVN driver does support VLAN tenant networks when used
with OVN version 2.11 (or higher).

* DNS
@@ -44,6 +44,12 @@ services:
Native implementation. Since the version 2.8 OVN contains a built-in
DNS implementation.

* Port Forwarding

The OVN driver supports port forwarding as an extension of floating
IPs. Enable the 'port_forwarding' service plugin in neutron configuration
files to use this feature.


The following Neutron API extensions are supported with OVN:

@@ -100,3 +106,5 @@ The following Neutron API extensions are supported with OVN:
+----------------------------------+---------------------------+
| Domain Name System (DNS) | dns_integration |
+----------------------------------+---------------------------+
| Port Forwarding | port_forwarding |
+----------------------------------+---------------------------+

+ 11
- 33
doc/source/ovn/gaps.rst View File

@@ -8,27 +8,6 @@ It is not a complete list, but is enough to be used as a starting point for
implementors working on closing these gaps. A TODO list for OVN is located
at [1]_.

* Port forwarding

Currently ML2/OVS supports Port Forwarding in the North/South plane.
Specific L4 Ports of the Floating IP can be directed to a specific
FixedIP:PortNumber of a VM, so that different services running in a VM
can be isolated, and can communicate with external networks easily.

This is a relatively new extension, support would need to be added to OVN.

One possible way would be to use the OVN native load balancing feature.
An OVN load balancer is expressed in the OVN northbound load_balancer
table. Normally the VIP and its members are expressed as [2]_:

.. code-block:: console

VIP:PORT = MEMBER1:MPORT1, MEMBER2:MPORT2

The same could be extended for port forwarding as:

FIP:PORT = PRIVATE_IP:PRIV_PORT

* Security Groups logging API

Currently ML2/OVS, with the OpenvSwitch firewall, supports a log file where
@@ -48,9 +27,9 @@ at [1]_.

Currently the Neutron L3-agent supports floating IP and gateway IP bandwidth
limiting based on Linux TC. Networking-ovn L3 had a prototype
implementation [3]_ based on the meter of openvswitch [4]_ utility that
implementation [2]_ based on the meter of openvswitch [3]_ utility that
has been abandoned. This is supported in user space datapath only, or
kernel versions 4.15+ [5]_.
kernel versions 4.15+ [4]_.

* QoS Minimum Bandwidth support

@@ -67,7 +46,7 @@ at [1]_.
The core OVN DHCP server implementation does not have support for
sending different boot options based on the ``gpxe`` DHCP Option
(no. 175). Also, Ironic uses dnsmasq syntax when configuring the DHCP
options for Neutron [6]_ which is not understood by the OVN driver.
options for Neutron [5]_ which is not understood by the OVN driver.

* Availability Zones

@@ -78,7 +57,7 @@ at [1]_.
to see how they would fit in the OVN model. For example, in the router
availability zone case, the OVN driver should schedule the router
ports on a Chassis (a "node" in OVN terms) where the availability
zones match with the router availability zones [7]_.
zones match with the router availability zones [6]_.

* Routed provider networks

@@ -86,17 +65,16 @@ at [1]_.
represent multiple L2 domains (segments). The OVN driver does not
understand this feature yet and will need to account for multiple
physical networks associated with a single OVN Logical Switch (a
network in Neutron terms) [8]_.
network in Neutron terms) [7]_.


References
----------

.. [1] https://github.com/ovn-org/ovn/blob/master/TODO.rst
.. [2] https://github.com/ovn-org/ovn/blob/master/ovn-nb.ovsschema#L160
.. [3] https://review.opendev.org/#/c/539826/
.. [4] https://github.com/openvswitch/ovs/commit/66d89287269ca7e2f7593af0920e910d7f9bcc38
.. [5] https://github.com/torvalds/linux/blob/master/net/openvswitch/meter.h
.. [6] https://github.com/openstack/ironic/blob/123cb22c731f93d0c608d791b41e05884fe18c04/ironic/common/pxe_utils.py#L447-L462>
.. [7] https://docs.openstack.org/neutron/latest/admin/config-az.html
.. [8] https://bugs.launchpad.net/neutron/+bug/1865889
.. [2] https://review.opendev.org/#/c/539826/
.. [3] https://github.com/openvswitch/ovs/commit/66d89287269ca7e2f7593af0920e910d7f9bcc38
.. [4] https://github.com/torvalds/linux/blob/master/net/openvswitch/meter.h
.. [5] https://github.com/openstack/ironic/blob/123cb22c731f93d0c608d791b41e05884fe18c04/ironic/common/pxe_utils.py#L447-L462>
.. [6] https://docs.openstack.org/neutron/latest/admin/config-az.html
.. [7] https://bugs.launchpad.net/neutron/+bug/1865889

+ 1
- 0
doc/source/ovn/index.rst View File

@@ -9,6 +9,7 @@ OVN Driver
:maxdepth: 1

migration.rst
port_forwarding.rst
gaps.rst
dhcp_opts.rst
faq/index.rst

+ 105
- 0
doc/source/ovn/port_forwarding.rst View File

@@ -0,0 +1,105 @@
.. _port_forwarding:

ML2/OVN Port forwarding
=======================

ML2/OVN supports Port Forwarding (PF) across the North/South data plane.
Specific L4 Ports of the Floating IP (FIP) can be directed to a specific
FixedIP:PortNumber of a VM, so that different services running in a VM
can be isolated, and can communicate with external networks easily.

OVN's native load balancing (LB) feature is used for providing this
functionality. An OVN load balancer is expressed in the OVN northbound
load_balancer table for all mappings for a given FIP+protocol. All PFs
for the same FIP+protocol are kept as Virtual IP (VIP) mappings inside a
LB entry. See the diagram below for an example of how that looks like:

.. code-block:: none

VIP:PORT = MEMBER1:MPORT1, MEMBER2:MPORT2

The same is extended for port forwarding as:

FIP:PORT = PRIVATE_IP:PRIV_PORT

Neutron DB OVN Northbound DB

+---------------------+ +---------------------------------+
| Floating IP AA | | Load Balancer AA UDP |
| | | |
| +-----------------+ | | |
| | Port Forwarding | | +----------->AA:portA => internal IP1:portX |
| | | | | | |
| | External PortA +-----+ +------->AA:portB => internal IP2:portX |
| | Fixed IP1 PortX | | | | |
| | Protocol: UDP | | | +---------------------------------+
| +-----------------+ | |
| | | +---------------------------------+
| +-----------------+ | | | Load Balancer AA TCP |
| | Port Forwarding | | | | |
| | | | | | |
| | External PortB +---------+ +--->AA:portC => internal IP3:portX |
| | Fixed IP2 PortX | | | | |
| | Protocol: UDP | | | +---------------------------------+
| +-----------------+ | |
| | |
| +-----------------+ | |
| | Port Forwarding | | |
| | | | | +---------------------------------+
| | External PortC | | | | Load Balancer BB TCP |
| | Fixed IP3 PortX +-------------+ | |
| | Protocol: TCP | | | |
| +-----------------+ | +---------->BB:portD => internal IP4:portX |
| | | | |
+---------------------+ | +---------------------------------+
|
| +-------------------+
| | Logical Router X1 |
+---------------------+ | | |
| Floating IP BB | | | Load Balancers: |
| | | | AA UDP, AA TCP |
| +-----------------+ | | +-------------------+
| | Port Forwarding | | |
| | | | | +-------------------+
| | External PortD | | | | Logical Router Z1 |
| | Fixed IP4 PortX +------+ | |
| | Protocol: TCP | | | Load Balancers: |
| +-----------------+ | | BB TCP |
+---------------------+ +-------------------+

The OVN LB entries have names that include the id of the FIP and a protocol suffix.
That protocol portion is needed because a single FIP can have multiple UDP and TCP port
forwarding entries while a given LB entry can either be one or the other protocol (not both).
Based on that, the format used to specify an LB entry is:

.. code-block:: ini

pf-floatingip-<NEUTRON_FIP_ID>-<PROTOCOL>

A revision value is present in external_ids of each OVN load balancer entry.
That number is synchronized with floating IP entries (NOT the port forwarding!) of the Neutron
database.

In order to differentiate a load balancer entry that was created by port forwarding
vs load balancer entries maintained by ovn-octavia-provider, the external_ids field also
has an owner value:

.. code-block:: python

external_ids = {
ovn_const.OVN_DEVICE_OWNER_EXT_ID_KEY: PORT_FORWARDING_PLUGIN,
ovn_const.OVN_FIP_EXT_ID_KEY: pf_obj.floatingip_id,
ovn_const.OVN_ROUTER_NAME_EXT_ID_KEY: rtr_name,
neutron:revision_number: fip_obj.revision_number,
}

The following registry (API) neutron events trigger the OVN backend to map port forwarding
into LB:

.. code-block:: python

@registry.receives(PORT_FORWARDING_PLUGIN, [events.AFTER_INIT])
def register(self, resource, event, trigger, payload=None):
registry.subscribe(self._handle_notification, PORT_FORWARDING, events.AFTER_CREATE)
registry.subscribe(self._handle_notification, PORT_FORWARDING, events.AFTER_UPDATE)
registry.subscribe(self._handle_notification, PORT_FORWARDING, events.AFTER_DELETE)

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