[Openstack-operators] VM with a public IP

Matt Joyce matt at nycresistor.com
Mon Aug 13 21:00:43 UTC 2012

Paul by default openstack operates under a model in which instances
default to a private address range.

For assigning public IPs or IPs outside of that range, it has a pool
of addresses you configure and make available to it referred to as
floating IP addresses.

You would want to make your IPs available there for mapping.

Obviously your configuration bucks the norm in this case.

The right answer here is to use an IP allocation that is not handed
out by DHCP but is just available for openstack to handle on its own.
I understand however that some organizations have some pretty
draconian policies and not always is this allowed.   While I would
push strenuously for an exception from this requirement I understand
that may not be an option.

In that case, you have a problem.  If you can convince your network
controllers to allocated all of the IPs in a dhcp block and retain
that ownership on your own you SHOULD be able to use them for
instances as the network controller currently simply nats the
addresses to their private 'openstack' addresses.

I think that's probably the best solution for you.

Hope that helps.


On Mon, Aug 13, 2012 at 1:31 PM, Paul Walton <paul.d.walton at gmail.com> wrote:
> Hello,
> I have been reading tutorials on installing OpenStack on Ubuntu, and so far
> they all involve giving the VMs a private IP from the Nova configs.
> However, in my case I will need to generate VMs that have a publicly
> accessible IP address, and this address will be handed out by a DHCP server
> that I do not control and is external to OpenStack.  I can do this just fine
> using standard KVM on our current VM server, but I haven't see yet how
> OpenStack allows this to occur.  For example, several of our current VMs run
> class websites, and some have static IPs assigned to them, while some are
> dynamically assigned.  These must be accessable from the Internet for our
> students to access.  If someone could point me to a document or tutorial on
> how to do this in OpenStack then that would be great!
> Thanks!
> --
> Paul Walton
> University of Arkansas
> College of Engineering
> CSCE Technical Support Team
> J.B. Hunt Building, Room 440
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> OpenStack-operators mailing list
> OpenStack-operators at lists.openstack.org
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