Open Stack

> On 03/13/2015 05:54 AM, Georgios Dimitrakakis wrote:
>>> On 03/12/2015 06:24 PM, Georgios Dimitrakakis wrote:
>>>> Hello!
>>>>
>>>> I am facing a rather weird issue and would like to know if anyone 
>>>> has
>>>> faced it before and the way you have solved it (if any).
>>>>
>>>> Firstly, I 'd like to let you know that I am running Icehouse with 
>>>> Nova-Legacy
>>>> Networking.
>>>>
>>>> I have an application that launches and terminates VMs very 
>>>> frequently and
>>>> automatically assigns to them
>>>> floating IP addresses.
>>>>
>>>> As a result if an IP has been used once then the second time that 
>>>> is being used
>>>> cannot be reached for at
>>>> least 20minutes (this is the time frame if the newly launched VM 
>>>> gets the same
>>>> IP address from one that
>>>> has just been terminated). Furthermore, this issue only happens 
>>>> when the second
>>>> VM is launched on a
>>>> different physical node (hypervisor) than the first one.
>>>>
>>>> I believe that I have identified the problem to be ARP Caching on 
>>>> the router
>>>> side since if I do:
>>>>
>>>> arping -U -I {Interface-Name} {IP-Address}
>>>>
>>>> in order to update the ARP Caches of the neighbors immediately the 
>>>> new VM can be
>>>> reached on its floating
>>>> IP address.
>>>>
>>>>
>>>> Is this the proper way of solving it?
>>>>
>>>> Can I somehow "instruct" OpenStack not to use the first available 
>>>> IP address
>>>> everytime but on a random order
>>>> or the one that hasn't been used for enough time?
>>>>
>>>> Any other thoughts?
>>>
>>>
>>> Just a thought, have you tried enabling "send_arp_for_ha" in 
>>> nova.conf?
>>>
>>> Chris
>>>
>>
>>
>> Hi Chris! Thx for the feedback!
>>
>> send_arp_for_ha = True
>>
>> is already enabled in all nodes (controller and compute).
>>
>> Can I somehow verify that it's working?
>
> You should be able to verify with a packet sniffer somewhere on your 
> network.
>
>> How often is it sending the ARP request? Does it send it every time 
>> nova configuration is changing?
>
> I'm very much *not* an expert in this area, so I'm afraid I'm not the
> right person to ask about that.
>
>
> Chris

 Chris,

 thanks for the feedback. Any idea on what to sniff for?

 George