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
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