[Openstack] Routing from instances to floating ips in nova-network -- possible?

Andrew Bogott abogott at wikimedia.org
Thu May 7 17:30:14 UTC 2015


On 5/7/15 2:34 AM, Antonio Messina wrote:
> On Wed, May 6, 2015 at 10:56 PM, Andrew Bogott <abogott at wikimedia.org> wrote:
>>      Since time immemorial, I've accepted as a fact of life that routing from
>> a nova instance to another instance via floating ip is impossible.  We've
>> coped with this via a hack in dnsmasq, setting an alias to rewrite public
>> IPs to the corresponding internal IP.
> Have you checked this serverfault question[0]? The issue is different
> though: VM not being able to contact its own floating iP, but maybe
> it's related. It also contains links to relevant bugs.
I did see that, although it seems to be a subcase of my issue (implying 
that routing is working for people in general, just not from a host to 
itself.)

I'm glad to hear that it works for you!  I just now tried setting 
force_snat_range for my floating IP range but I'm still not getting any 
pings.  Strangely if I restart nova-network things work for a minute or 
two, then return to the status quo.  That means that no matter what I 
change, it looks like it worked, for a minute :)

-A

>
> We have a Folsom deployment where we patched nova-network to add the
> proper SNAT and DNAT rules to fix this, and I can confirm that I can
> ssh from a VM to the other using the public IP. I would post the patch
> but since you are running Icehouse they are probably not relevant.
>
> [0]: http://serverfault.com/questions/460348/why-cant-openstack-vm-reach-itself-via-its-floating-ip
>
> .a.
>





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