[Openstack-operators] VM with a public IP
matt at nycresistor.com
Mon Aug 13 22:53:56 UTC 2012
Paul, it's a cloud. It's a fairly reasonable design assumption to
believe anyone launching such a service has at least some moderate
level of control over their own resources. But hell, maybe I'm just
not seeing some awesome new way to use openstack.
Here's a thought for a simple external work around. You basically
create your own router for your cloud.
You get a grab bag of IPs on a bunch of virtual interfaces you fire
up on your router interface facing the university network...
you take these and setup some nat rules to map them
220.127.116.11 <--> 192.168.250.2
18.104.22.168 <--> 192.168.250.3
22.214.171.124 <--> 192.168.250.4
126.96.36.199 <--> 192.168.250.5
188.8.131.52 <--> 192.168.250.6
then setup a gateway interface ala
Then you configure openstack to route its public interface on that
192.168.250.0/24 network. And that's your floating ip range.
Openstack doesn't care. And you are still direct natting full ips.
So it's a bit of a kludge but from the description this sounds like a
kludge is unavoidable atm.
On Mon, Aug 13, 2012 at 2:55 PM, Paul Walton <paul.d.walton at gmail.com> wrote:
> Unfortunately, I do not manage the network, and do not have access to the
> DHCP server. This means that I do not have a subnet of IPs that I can
> simply hand out freely to my VMs. If I want a VM to have a public IP then
> it must make a request to the campus DHCP server. There are special cases
> where I can assign static IPs to servers, but this is infeasible for the
> majority of the VMs I will create since they will be used by students to
> complete assignments in class, and will only exist during the course of a
> So, as I understand things so far, OpenStack assumes that I have my own
> subnet of public IPs that I can freely use for my VMs? I can't imagine this
> being a reasonable design assumption to make on their part. Perhaps I'm
> overlooking something?
> On Mon, Aug 13, 2012 at 4:40 PM, Matt Joyce <matt.joyce at cloudscaling.com>
>> I was thinking that as well. But the only reason I could think of that
>> he'd be forced to grab public IPs from dhcp was that he had no access to the
>> DHCP server and network infrastructure. I just kind of assumed that would
>> mean that nova would not be able to allocate the IP for intance in any
>> manner congruent with nova's needs.
> Paul Walton
> University of Arkansas
> College of Engineering
> CSCE Technical Support Team
> J.B. Hunt Building, Room 440
> OpenStack-operators mailing list
> OpenStack-operators at lists.openstack.org
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