Open Stack

 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?


 Regards,

 George