L3 agent support dual-NAT mode

Registered by Chengli Xu on 2013-06-27

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

Blueprint information

Status:
Complete
Approver:
Mark McClain
Priority:
Undefined
Drafter:
None
Direction:
Needs approval
Assignee:
Chengli Xu
Definition:
Obsolete
Series goal:
None
Implementation:
Unknown
Milestone target:
milestone icon next
Completed by
Armando Migliaccio

Sprints

Whiteboard

Dec-07-2015(armax): If someone is interested in pursuing it, this must be re-submitted according to guidelines defined in [1].

[1] http://docs.openstack.org/developer/neutron/policies/blueprints.html

---------------

16-Jul: Adding to Next the next milestone. The spec of this feature should have more details and this discussed at the Icehouse summit.

Gerrit address: https://review.openstack.org/#/c/34680/

Gerrit topic: https://review.openstack.org/#q,topic:bp/l3-dual-nat-mode,n,z

Addressed by: https://review.openstack.org/34680
    Implement l3 agent dual-NAT mode support

(?)

Work Items

Work items:
Basic dual NAT support in L3 Agent: DONE
Support floating ip: INPROGRESS
Update quantum API: TODO

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