[openstack-dev] [neutron][networking-ovn] Integration with OVN NAT gateway (Proposal)
Bhalachandra Banavalikar
bhal.banavalikar at us.ibm.com
Tue Jun 7 23:39:33 UTC 2016
Can you please provide more details on lgrp and lip ports (last bullet in
section 1)?
Thanks,
Bhal
From: Amitabha Biswas <azbiswas at gmail.com>
To: "OpenStack Development Mailing List (not for usage questions)"
<openstack-dev at lists.openstack.org>
Cc: Chandra Sekhar Vejendla/San Jose/IBM at IBMUS
Date: 06/07/2016 01:56 PM
Subject: [openstack-dev] [neutron][networking-ovn] Integration with OVN
NAT gateway (Proposal)
This proposal outlines the modifications needed in networking-ovn
(addresses https://bugs.launchpad.net/networking-ovn/+bug/1551717) to
provide Floating IP (FIP) and SNAT using the L3 gateway router patches.
http://patchwork.ozlabs.org/patch/624312/
http://patchwork.ozlabs.org/patch/624313/
http://patchwork.ozlabs.org/patch/624314/
http://patchwork.ozlabs.org/patch/624315/
http://patchwork.ozlabs.org/patch/629607/
Diagram:
+-------+ +-------+
| NET 1 | | NET 2 |
+-------+ +-------+
| |
| ********* |
| ** ** |
| ** * * ** |
+---RP1 * DR * RP2 --+
** * * **
** **
*********
DTRP (168.254.128.2)
|
|
|
+------------------+
| Transit Network |
| 169.254.128.0/30 |
+------------------+
|
|
|
|
GTRP (169.254.128.1)
*******
** **
** * * ** +------------------+
* GW *-----------------| Provider Network |
** * * ** +------------------+
** **
*******
New Entities:
OVN Join/Transit Networks
One per Neutron Router - /30 address space with only 2 ports
for e.g. 169.254.128.0/30
Created when an external gateway is added to a router.
One extra datapath per router with an External Gateway.
(Alternate option - One Transit Network in a deployment, IPAM
becomes a headache - Not discussed here).
Prevent Neutron from using that /30 address space. Specify in
networking-ovn conf file.
Create 1 new “Join” neutron network (to represent all Join OVN
Networks) in the networking-ovn.
Note that it may be possible to replace the Join/Transit
network using Router Peering in later versions (not discussed
here).
Allocate 2 ports in the Join network in the networking-ovn
plugin.
Logical Gateway Transit Router Port (gtrp), 169.254.128.1
Logical Distributed Transit Router Port (dtrp),
169.254.128.2
Note that Neutron only sees 1 Join network with 2 ports; OVN
sees a replica of this Join network as a new Logical Switch for
each Gateway Router. The mapping of OVN Logical Switch(es) Join
(s) to Gateway Router is discussed in OVN (Default) Gateway
Routers below.
Note that the MAC addresses of lgrp and lip will be the same on
each OVN Join Network, but because they are in different
branches of the network topology it doesn’t matter.
OVN (Default) Gateway Routers:
One per Neutron Router.
2 ports
Logical Gateway Transit Router Port (gtrp), 169.254.128.1
(same for each OVN Join network).
External/Provider Router Port (legwrp), this is allocated
by neutron.
Scheduling - The current OVN gateway proposal relies on the
CMS/nbctl to decide on which hypervisor (HV) to schedule a
particular gateway router.
A setting on the chassis (new external_id key or a new
column) that allows the hypervisor admin to specify that
a chassis can or cannot be used to host a gateway router
(similar to a network node in OpenStack). Default - Allow
(for compatibility purposes).
The networking-ovn plugin picks up the list of
“candidate” chassis from the Southbound DB and uses an
existing scheduling algorithm
Use a simple random.choice i.e. ChanceScheduler
(Version 1)
Tap into the neutron’s LeastRouterScheduler - but
that requires the networking-ovn (or some a hacked
up version of the L3 agent) to imitate the L3 agent
running on various network nodes.
Populate the SNAT and DNAT columns in the logical router table.
This is under review in OVS -
http://openvswitch.org/pipermail/dev/2016-June/072169.html
Create static routing entry in the gateway router to route
tenant bound traffic to the distributed logical router.ar gate
Existing Entities:
Distributed Logical Routers:
Set the default gateway of the distributed logical router to
the IP Address of the corresponding Logical Gateway Transit
Router Port (169.254.128.1).
It would be good to get some feedback on this strategy. Guru mentioned that
he saw a need for ARP response across multiple gateway routers, we don’t
see that requirement in this design/use-case.
Thanks
Amitabha (azbiswas) and Chandra (chandrav)
__________________________________________________________________________
OpenStack Development Mailing List (not for usage questions)
Unsubscribe: OpenStack-dev-request at lists.openstack.org?subject:unsubscribe
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20160607/99c78bc4/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: graycol.gif
Type: image/gif
Size: 105 bytes
Desc: not available
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20160607/99c78bc4/attachment.gif>
More information about the OpenStack-dev
mailing list