You have to set two variables in the nova.conf file apparently
("send_arp_for_ha" and "send_arp_for_ha_count"):https://github.com/openstack/nova/blob/3658e1015a2f7cb7c321cc1a0adfda37757fd80b/nova/network/linux_net.py#L764 On Fri, Mar 13, 2015 at 2:00 PM, Georgios Dimitrakakis <gior...@acmac.uoc.gr > wrote: > > 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 > > _______________________________________________ > Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/ > openstack > Post to : openstack@lists.openstack.org > Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/ > openstack >
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