[Openstack-operators] ML2/OVS odd GRE brokenness

Mohammed Naser mnaser at vexxhost.com
Wed Nov 9 15:18:25 UTC 2016


Have you tried turning off all agents, shut off all VMs on that node, destroy br-int and be-tun, start neutron agents and try again?

Sent from my iPhone

> On Nov 9, 2016, at 9:51 AM, Jonathan D. Proulx <jon at csail.mit.edu> wrote:
> 
> 
> Also I have restarted openvswitch-agent on both sides of the broken
> link and it made no difference...
> 
> On Tue, Nov 08, 2016 at 05:43:27PM -0500, Jonathan Proulx wrote:
> :
> :I have an odd issue that seems to just be affecting one private
> :network for one tenant, though I saw a similar thing on a different
> :project network recently which I 'fixed' by rebooting the hypervisor.
> :Since this has now (maybe) happened twice I figure I should try to
> :understand what it is.
> :
> :Given the following four VMs on 4 different hypervisors
> :
> :vm1 on Hypervisor1
> :vm2 on Hypervisor2
> :vm3 on Hypervisor3
> :-------------------
> :vm4 on Hypervisor4
> :
> :
> :vm1 -> vm3 talk fine among themselves but none to 4
> :
> :examining ping traffic transiting from vm1-vm4 I can see arp requests
> :and responses at vm4 and GRE encapsulated ARP responses on
> :Hypervisor1's physical interface.
> :
> :They look the same to me (same ecap id) coming in as the working vms
> :traffic, but they never make it to the qvo device which is before
> :iptables sec_group rules are applied at the tap device.
> :
> :attempting to tare down and recreate this resuls in the same first 3
> :work last one doesn't split (possibly becuase scheduler puts them in
> :the same place? haven't checked) 
> :
> :ovs-vsctl -- set Bridge br-int mirrors=@m  -- --id=@snooper2 get Port snooper2  -- --id=@gre-801e0347 get Port gre-801e0347 -- --id=@m create Mirror name=mymirror select-dst-port=@gre-801e0347 select-src-port=@gre-801e0347 output-port=@snooper2
> :
> :tcpdump -i snooper2 
> :
> :Only sees ARP requests but no response, what's broken if I can see GRE
> :encap ARP responses on physical interface but not on gre-<hex>
> :interface?  And why is it not broken for all tunnels endpoints?
> :
> :Oddly if I boot a 5th VM on a 5th hypervisor it can talk to 4 but not 1-3 ...
> :
> :hypervisors are Ubuntu 14.04 running Mitaka from cloud archive w/
> :xenial-lts kernels (4.4.0)
> :
> :-Jon
> :
> :-- 
> 
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