neutron

[Quantum] Control the public IP address assigned to a router by quantum router-gateway-set

Asked by RobertoCanonico on 2013-06-04

Short question:
is it possible to control the IP address that is given to a router
by the quantum router-gateway-set command ?
In my setup, I have a physical Provider Network associated to a public (routable) IP address range used at my site (X.Y.Z.0/24).
I have created an ExternalNet network by the CLI commands:

quantum net-create ExternalNet --router:external=True
quantum subnet-create ExternalNet X.Y.Z.0/24 --enable_dhcp=False --gateway_ip=X.Y.Z.254

When I issue the quantum router-gateway-set command, the public interface
of the router gets the first address of the X.Y.Z.0/24 range, i.e. X.Y.Z.1,
which, by pure chance, is not used in my physical network.
My setup seems to work OK, VMs are able to ping any other host
in the external network X.Y.Z.0/24, as well as any other Internet host,
through the physical router X.Y.Z.254.

I wonder if is possible to assign to the "virtual" router implemented in Quantum a given address in the range of addresses associated to the external subnet, e.g. X.Y.Z.33.
This might also be useful in the "Per-tenant Routers with Private Networks" use case.
Many thanks in advance for your replies.
Roberto

Question information

Language:: English Edit question

Status:: Solved

For:: neutron Edit question

Assignee:: No assignee Edit question

Solved by:: yong sheng gong

Solved:: 2015-09-14

Last query:: 2015-09-14

Last reply:: 2013-06-07

Revision history for this message

yong sheng gong (gongysh) said on 2013-06-05:

it IP of the public interface, qgxxx of router is from allocation pool of external network (--router:external=True). the allocation pool should not overlap with IPs of your physical network. why do u want to specify the quantum router's qgxx interface?

Revision history for this message

Baohua Yang (yangbaohua) said on 2013-06-05:

Try
quantum subnet-create ExternalNet X.Y.Z.Q/24 --enable_dhcp=False --gateway_ip=X.Y.Z.254
Where X.Y.Z.Q is the ip you wanna set the router to.

Revision history for this message

RobertoCanonico (roberto-canonico) said on 2013-06-06:

@ Baohua Yang (yangbaohua):
thanks for your suggestion, unfortunately it did not work to me, the router still gets the X.Y.Z.1 address

@ yong sheng gong (gongysh):
maybe I am doing something conceptually wrong.
My problem is that I can only use a sparse subset of addresses in the external X.Y.Z.0/24 public range.
The IP address of the physical router is X.Y.Z.254.
My target scenario is called "Provider Router with Private Networks" in the Quantum documentation
(see http://docs.openstack.org/trunk/openstack-network/admin/content/figures/1/figures/UseCase-SingleRouter.png for a reference).
The IP address I would like to assign to my Provider Router is, say, X.Y.Z.33.
My understanding is that I only need one public IP address, as I don't need public floating IP addresses to attach to specific VMs.
If I restrict the size of the allocation pool to a small range including X.Y.X.33, I am not able to ping the
physical router X.Y.X.254 from my VMs, and hence no Internet connectivity is allowed to them.