Bug 1042455

Summary: [RFE][neutron]: L3 agent support dual-NAT mode
Product: Red Hat OpenStack Reporter: RHOS Integration <rhos-integ>
Component: RFEsAssignee: RHOS Maint <rhos-maint>
Status: CLOSED UPSTREAM QA Contact:
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: unspecifiedCC: markmc, yeylon
Target Milestone: ---Keywords: FutureFeature
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
URL: https://blueprints.launchpad.net/neutron/+spec/l3-dual-nat-mode
Whiteboard: upstream_milestone_next upstream_status_unknown upstream_definition_obsolete
Fixed In Version: Doc Type: Enhancement
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-03-19 17:44:55 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description RHOS Integration 2013-12-12 22:20:26 UTC 
Cloned from launchpad blueprint https://blueprints.launchpad.net/neutron/+spec/l3-dual-nat-mode.

Description:

With dual-NAT mode enabled, each router has a 'private' gateway port, which is not maintained by Quantum. All those gateway ports of the routers in a L3 agent are bridged to br-ex and belong to the same local subnet (e.g. 169.254.4.0/24). The subnet's gateway is another tap device in the network node host and bridged to br-ex as well. There will be two NAT ops when a VM access outside network, one is between tenant network and "private" subnet, and the other is between "private" subnet and destination network.

Dual-NAT mode could bring two benefits:
* reduce the usage of public IP address
* VMs can access all the networks that can be accessed by network node host

Specification URL (additional information):

None