Open Stack

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