[Openstack] Floating IP issues in multiple cloud installs.

Ken D'Ambrosio ken at jots.org
Mon Jun 19 12:51:32 UTC 2017


Hi, all.  We've got two Canonical Newton installs using VLANs and we're 
having intermittent issues we simply can't figure out.  (Note that a 
third installation using flat networks is not having this issue.)  
Floating IPs set up and work... sporadically.

* Stateful connections (e.g., SSH) often drop after seconds of use to 
both the FIP and when SSH'd in from the
* We see RSTs in our TCP dumps
* Pings work for a while, then don't.
* We see lots of ARP requests -- even one right after another -- to 
resolve hosts on the internal subnets:
05:43:25.859448 ARP, Request who-has 80.0.0.3 tell 80.0.0.1, length 28
05:43:25.859563 ARP, Reply 80.0.0.3 is-at fa:16:3e:28:af:77, length 28
05:43:25.964417 ARP, Request who-has 80.0.0.3 tell 80.0.0.1, length 46
05:43:25.964572 ARP, Reply 80.0.0.3 is-at fa:16:3e:28:af:77, length 28
05:43:26.963989 ARP, Request who-has 80.0.0.3 tell 80.0.0.1, length 46
05:43:26.964156 ARP, Reply 80.0.0.3 is-at fa:16:3e:28:af:77, length 28

80.0.0.1 is the qrouter.  I can't imagine why it asked -- and was ACK'd 
in each case -- three times in just over a second.  In hindsight, I 
should have checked to have seen if the ACK showed up in the qrouter's 
ARP table.  Next time...

I'd be happy to go into more detail, but was curious if anyone has seen 
an issue along these lines.

Thanks,

-Ken



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