[Openstack] Auto Assigned Floating IPs take a long time to associate

Kevin Jackson kevin at linuxservices.co.uk
Wed Mar 28 13:09:38 UTC 2012


I launched a new instance:


I ssh'd to 172.29.1.4 and my instance was running but nova list shows no
floating IP assigned.

nova list
+--------------------------------------+--------------+--------+----------------------------------+
|                  ID                  |     Name     | Status |
  Networks             |
+--------------------------------------+--------------+--------+----------------------------------+
| ff796bfa-0582-4ccb-8af0-b112b0c15326 | test1        | ACTIVE |
development=10.2.0.5             |
+--------------------------------------+--------------+--------+----------------------------------+

The database says this is assigned

mysql> select * from floating_ips where address="172.29.1.4"\G;
*************************** 1. row ***************************
   created_at: 2012-03-26 08:32:20
   updated_at: 2012-03-28 13:01:31
   deleted_at: NULL
      deleted: 0
           id: 4
      address: 172.29.1.4
  fixed_ip_id: 1030
   project_id: 01b1e8df305b49998e6ecbac02cb9f70
         host: openstack1
auto_assigned: 1
         pool: nova
    interface: eth5
1 row in set (0.00 sec)

Cheers,

Kev

On 28 March 2012 14:00, Day, Phil <philip.day at hp.com> wrote:

> Hum – very odd.   Have you looked in the DB tables to see if its assigned
> properly in there ?     If its not getting assigned in the DB then there’s
> a risk that it could be used again by the next instance.****
>
> ** **
>
> *From:* uksysadmin at gmail.com [mailto:uksysadmin at gmail.com] *On Behalf Of *Kevin
> Jackson
> *Sent:* 28 March 2012 13:58
> *To:* Day, Phil
> *Cc:* openstack at lists.launchpad.net
> *Subject:* Re: [Openstack] Auto Assigned Floating IPs take a long time to
> associate****
>
> ** **
>
> Cheers Phil,****
>
> It's not that I can't get to the instances - I'd assume it was an ARP
> issue at that point - its the fact that Nova hasn't notified me that it has
> assigned an IP address: see my additional note where I guessed an IP
> address it would've assigned and I could access it... but management tools
> were still blissfully unaware.****
>
> I used to have a working Diablo set up with pretty much this same set up
> (this is under Essex RC1 / Ubuntu 12.04) and never had an issue.****
>
> ** **
>
> This just looks like it has assigned the IP to the instance, but hasn't
> notified the management underbelly of MySQL so any client tools
> interrogating the instance doesn't see that nova has done this work already.
> ****
>
> ** **
>
> Kev****
>
> On 28 March 2012 13:04, Day, Phil <philip.day at hp.com> wrote:****
>
> Are you sure that its Nova that is taking the time to associate the IP,
> and not an ARP issue in your network ?****
>
>  ****
>
> I’ve seen this behaviour when quickly reusing floating IP addresses – Nova
> does the assignment and sends out an unsolicited ARP response (assuming you
> have the “send_arp_for_ha” flag set) – this is in
> network/linux_net.bind_floating_ip().   However  sometimes an unsolicited
> APR response can get dropped in the network, ad so if the switch doesn’t
> see this message and it already has a previous ARP mapping in its cache
> then it will continue to try and send traffic to the previous user of that
> address until the cache times out. ****
>
>  ****
>
> Note that some network failover systems send multiple requests to get more
> certainty around this (for example I’ve seen a VPN solution use 6 messages).
> ****
>
>  ****
>
> There are a couple of things you could try:****
>
>  ****
>
> -          Add a flag to be able to increase the number of arp_responses
> sent****
>
> -          Change the allocation of floating_ips so that instead of
> picking the first free one in the DB you pick the one which has been unused
> for the longest time (reduces the risk of reusing an address before the
> switch times out the entry in its cache).****
>
>  ****
>
> Phil****
>
>  ****
>
> *From:* openstack-bounces+philip.day=hp.com at lists.launchpad.net [mailto:
> openstack-bounces+philip.day=hp.com at lists.launchpad.net] *On Behalf Of *Kevin
> Jackson
> *Sent:* 28 March 2012 12:49
> *To:* openstack at lists.launchpad.net
> *Subject:* [Openstack] Auto Assigned Floating IPs take a long time to
> associate****
>
>  ****
>
> Hi all,****
>
> I've got the following set in my nova.conf:****
>
>  ****
>
> --auto_assign_floating_ip****
>
>  ****
>
> and I fire up an instance.****
>
> Everything works, a private IP is assigned... the instance is running...
> but it can take an inordinate amount of time (anywhere upwards of 2 mins,
> sometimes a lot longer) to associate a floating IP automatically.****
>
>  ****
>
> Anybody else experienced this?  Any clues on what I can do to troubleshoot
> this?  What is the condition when a Floating IP is assigned?  I've seen it
> assign Floating IPs very quickly when it is still Booting, not Active, say.
> ****
>
> Is it dependent on anything within the Instance itself?****
>
>  ****
>
> Cheers,****
>
>  ****
>
> Kev****
>
> --
> Kevin Jackson
> @itarchitectkev****
>
>
>
> ****
>
> ** **
>
> --
> Kevin Jackson
> @itarchitectkev****
>



-- 
Kevin Jackson
@itarchitectkev
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