[Openstack-operators] Two regions and so two metadata servers sharing the same VLAN

Kevin Benton blak111 at gmail.com
Fri Dec 4 00:29:01 UTC 2015

Well if that's the case then the metadata wouldn't work for every instance
that ARP'ed for the address and got the wrong response first.

On Thu, Dec 3, 2015 at 3:56 PM, Gilles Mocellin <
gilles.mocellin at nuagelibre.org> wrote:

> Hum, I don't think so. Things like hostname must be only known by the
> neutron instance of one region...
> Le 03/12/2015 00:01, Kevin Benton a écrit :
>> Are both metadata servers able to provide metadata for all instances of
>> both sides? If so, why not disable isolated metadata on one of the sides so
>> only one of the DHCP agents will respond?
>> On Thu, Nov 26, 2015 at 6:49 AM, <gilles.mocellin at nuagelibre.org <mailto:
>> gilles.mocellin at nuagelibre.org>> wrote:
>>     Hello stackers !
>>     Sorry, I also cross-posted that question here
>> https://ask.openstack.org/en/question/85195/two-regions-and-so-two-metadata-servers-sharing-the-same-vlan/
>>     But I think I can reach a wider audience here.
>>     So here's my problem.
>>     I'm facing an non-conventional situation. We're building a two
>>     region Cloud to separate a VMware backend and a KVM one. But both
>>     regions share the same 2 VLANs where we connect all our instances.
>>     We don't use routers, private network, floating IPs... I've
>>     enabled enable_isolated_metadata, so the metadata IP is inside the
>>     dhcp namespace and there's a static route in the created instances
>>     to it via the dhcp's IP. The two DHCPs could have been a problem
>>     but we will use separate IP ranges, and as Neutron sets static
>>     leases with the instances MAC address, they should not interfere.
>>     The question I've been asked is whether we will have network
>>     problems with the metadata server IP, that will
>>     exist in 2 namepaces on 2 neutron nodes but on the same VLAN. So
>>     they will send ARP packets with different MAC, and will perhaps
>>     perturb access to the metadata URL form the instances.
>>     Tcpdump shows nothing wrong, but I can't really test now because
>>     we haven't got yet the two regions. What do you think ?
>>     Of course, the question is not about why we choose to have two
>>     regions. I would have chosen Host Agregates to separate VMware and
>>     KVM, but cinder glance should have been configure the same way.
>>     And with VMware, it's not so feasible.
>>     Also, if we can, we will try to have separate networks for each
>>     regions, but it involves a lot of bureaucracy here...
>>     _______________________________________________
>>     OpenStack-operators mailing list
>>     OpenStack-operators at lists.openstack.org
>>     <mailto:OpenStack-operators at lists.openstack.org>
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
>> --
>> Kevin Benton
> _______________________________________________
> OpenStack-operators mailing list
> OpenStack-operators at lists.openstack.org
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators

Kevin Benton
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-operators/attachments/20151203/acf8e319/attachment.html>

More information about the OpenStack-operators mailing list