openstack team mailing list archive

["Xu (Simon) Chen" <xchenum@xxxxxxxxx>]

Here is what happened on a different thread:
http://buriedlede.blogspot.com/2012/07/debugging-networking-problems-with.html

I feel that using this might solve your issue too without changing iptables
drivers...

On Fri, Jul 20, 2012 at 12:58 PM, Wael Ghandour (wghandou) <
wghandou@xxxxxxxxx> wrote:

>
>   Yup, that has definitely helped, thanks a bunch Xu.
>
>
>  Regards,
>
>  Wael
>
>
>
>  On Jul 20, 2012, at 8:09 AM, Xu (Simon) Chen wrote:
>
> Yes, one solution is to modify the iptables driver, so that you don't SNAT
> for internal subnets...
>
>  So, at the beginning of the nova-network-floating-snat rules, you add
> something like this:
> -A nova-network-floating-snat -s 10.0.0.0/24 -d 10.0.0.0/24 -j ACCEPT
> ...
>  -A nova-network-floating-snat -s 10.0.88.16/32 -j SNAT --to-source pub1
> -A nova-network-floating-snat -s 10.0.16.7/32 -j SNAT --to-source pub2
> -A nova-network-floating-snat -s 10.0.4.11/32 -j SNAT --to-source pub3
>
>  Then it should solve the unnecessary NATting issue...
>
> On Fri, Jul 20, 2012 at 10:13 AM, Wael Ghandour (wghandou) <
> wghandou@xxxxxxxxx> wrote:
>
>>
>>   I can confirm that the VM traffic is undergoing NAT with using its
>> floating IP on the *private* interface of the nova-compute node when it
>> tries to reach the private address of the VMs belonging to the same tenant
>> and on other compute nodes. That obviously is breaking internal
>> connectivity....
>>
>>
>>  Regards,
>>
>>  Wael
>>
>>
>>
>>  On Jul 20, 2012, at 5:42 AM, Xu (Simon) Chen wrote:
>>
>> There was an issue that we saw in an earlier nova-network...
>>
>>  Due to multi_host configuration, the nova-network runs on every
>> nova-compute node. Therefore the floating IP assignment happens on the
>> compute nodes directly. So between two VMs within the same tenant on
>> different hosts, private->public SNAT happens unnecessarily.
>>
>>  Not sure if this is fixed in Essex...
>>
>> On Fri, Jul 20, 2012 at 3:49 AM, Edgar Magana (eperdomo) <
>> eperdomo@xxxxxxxxx> wrote:
>>
>>>  Folks,****
>>>
>>> ** **
>>>
>>> We are using Essex for our multi-host OpenStack deployment with Vlan
>>> Manager.****
>>>
>>> All the private IPs are working as expected in a multi-tenant scenario
>>> but the problem that we are seen is with Floating IPs.****
>>>
>>> ** **
>>>
>>> We have three tenants,  all of them are able to use  Floating IPs and
>>> then VMs are reachable from the public network but the inter VMs
>>> connectivity by private IPs is totally lost. Once we dissociate the
>>> Floating IPs to the corresponding VMs, the connectivity is back. The odd
>>> part is that we are seeing this behavior in just two of the three tenants
>>> that we have tested so far. ****
>>>
>>> ** **
>>>
>>> Is anyone aware of any bug or misconfiguration in Nova-network that
>>> could explain this behavior? We will be running more tests and we can
>>> provide detailed information of our environment if needed.****
>>>
>>> ** **
>>>
>>> Thanks for your help,****
>>>
>>> ** **
>>>
>>> Edgar****
>>>
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>>>
>>
>>
>
>