<p dir="ltr">Well, what value do you have for send_arp_for_ha_count ?</p>
<div class="gmail_quote">On 13 Mar 2015 17:11, "Georgios Dimitrakakis" <<a href="mailto:giorgis@acmac.uoc.gr">giorgis@acmac.uoc.gr</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">So according to that it sends ARP every time a floating IP is assigned at a VM. Am I right?<br>
<br>
If that is correct unfortunately it's not working :-(<br>
<br>
Any ideas how to debug it?<br>
<br>
Thanks a lot for your help!<br>
<br>
Regards,<br>
<br>
George<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Based on the code, it sends the gratuitous ARPs only when the floating<br>
IP is assigned to the VM, and its sent as many times as the user<br>
decided by configuring the "send_arp_for_ha_count" parameter in<br>
nova.conf<br>
<br>
So, to be safe, I would add the following in nova.conf and restart<br>
nova services.<br>
<br>
send_arp_for_ha=true<br>
send_arp_for_ha_count=20<br>
<br>
On Fri, Mar 13, 2015 at 2:54 PM, Georgios Dimitrakakis  wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
George,<br>
<br>
how often does it send the gratuitous ARP requests?<br>
<br>
Does it send it every time a network change is happening?<br>
<br>
Best,<br>
<br>
George<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
You have to set two variables in the nova.conf file apparently<br>
("send_arp_for_ha" and "send_arp_for_ha_count"):<br>
<br>
<br>
</blockquote>
<br>
</blockquote>
<br>
<a href="https://github.com/openstack/nova/blob/3658e1015a2f7cb7c321cc1a0adfda37757fd80b/nova/network/linux_net.py#L764" target="_blank">https://github.com/openstack/<u></u>nova/blob/<u></u>3658e1015a2f7cb7c321cc1a0adfda<u></u>37757fd80b/nova/network/linux_<u></u>net.py#L764</a><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
[4]<br>
[4]<br>
<br>
On Fri, Mar 13, 2015 at 2:00 PM, Georgios Dimitrakakis  wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On 03/13/2015 05:54 AM, Georgios Dimitrakakis wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On 03/12/2015 06:24 PM, Georgios Dimitrakakis wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hello!<br>
<br>
I am facing a rather weird issue and would like to know<br>
if<br>
anyone has<br>
faced it before and the way you have solved it (if<br>
any).<br>
<br>
Firstly, I d like to let you know that I am running<br>
Icehouse with Nova-Legacy<br>
Networking.<br>
<br>
I have an application that launches and terminates VMs<br>
very<br>
frequently and<br>
automatically assigns to them<br>
floating IP addresses.<br>
<br>
As a result if an IP has been used once then the second<br>
time that is being used<br>
cannot be reached for at<br>
least 20minutes (this is the time frame if the newly<br>
launched VM gets the same<br>
IP address from one that<br>
has just been terminated). Furthermore, this issue only<br>
happens when the second<br>
VM is launched on a<br>
different physical node (hypervisor) than the first<br>
one.<br>
<br>
I believe that I have identified the problem to be ARP<br>
Caching on the router<br>
side since if I do:<br>
<br>
arping -U -I {Interface-Name} {IP-Address}<br>
<br>
in order to update the ARP Caches of the neighbors<br>
immediately the new VM can be<br>
reached on its floating<br>
IP address.<br>
<br>
Is this the proper way of solving it?<br>
<br>
Can I somehow "instruct" OpenStack not to use the first<br>
available IP address<br>
everytime but on a random order<br>
or the one that hasnt been used for enough time?<br>
<br>
Any other thoughts?<br>
</blockquote>
<br>
Just a thought, have you tried enabling "send_arp_for_ha"<br>
in<br>
nova.conf?<br>
<br>
Chris<br>
</blockquote>
<br>
Hi Chris! Thx for the feedback!<br>
<br>
send_arp_for_ha = True<br>
<br>
is already enabled in all nodes (controller and compute).<br>
<br>
Can I somehow verify that its working?<br>
</blockquote>
<br>
You should be able to verify with a packet sniffer somewhere<br>
on<br>
your network.<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
How often is it sending the ARP request? Does it send it<br>
every<br>
time nova configuration is changing?<br>
</blockquote>
<br>
Im very much *not* an expert in this area, so Im afraid Im<br>
not<br>
the<br>
right person to ask about that.<br>
<br>
Chris<br>
</blockquote>
<br>
Chris,<br>
<br>
thanks for the feedback. Any idea on what to sniff for?<br>
<br>
George<br>
<br>
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