Hello Edwardh and all.

I keep getting these disconnects, were you able to find anything about to suggest changing ?

As I mentioned this machine different from the others where it never happened uses the ovirtmgmt network as VM network and has kernel 4.12 instead of the default 3.10 from CentOS 7.3. It seems a particular situation that is triggering this behavior but could not gather any hint yet.

I have tried to run a regular arping to force the bridge always learn the VMs MAC address but it doesn't seem to work and every in a while the bridge 'forgets' that particular VM mac address.
I have also even rebuilt the VM completely changing its operating system from Ubuntu 16.04 to CentOS 7.3 and the same problem happened.

Fernando

On 24/07/2017 18:20, FERNANDO FREDIANI wrote:

Hello Edward, this happened again today and I was able to check more details.

So:

- The VM stopped passing any network traffic.
- Checking 'brctl showmacs ovirtmgmt' it showed the VM's mac address missing.
- I then went to oVirt Engine, under VM's 'Network Interfaces' tab, clicked Edit and changed the Link State to Down then to Up and it recovered its connectivity.
- Another 'brctl showmacs ovirtmgmt' showed the VM's mac address learned again by the bridge.

This Node server has the particularity of sharing the ovirtmgmt with VMs. Could it possibly be the cause of the issue in any way ?

Thanks
Fernando

On 24/07/2017 09:47, FERNANDO FREDIANI wrote:

Not tried this yet Edwardh, but will do at next time it happens. THe source mac address should be the mac as the VM. I don't see any reason for it to change from within the VM ou outside.

What type of things would make the bridge stop learning a given VM mac address ?

Fernando

On 23/07/2017 07:51, Edward Haas wrote:

Have you tried to use tcpdump at the VM vNIC to examine if there is traffic trying to get out from there? And with what source mac address?

Thanks,

Edy,

On Fri, Jul 21, 2017 at 5:36 PM, FERNANDO FREDIANI <fernando.frediani@upx.com> wrote:

Has anyone had problem when using the ovirtmgmt bridge to connect VMs ?

I am still facing a bizarre problem where some VMs connected to this bridge stop passing traffic. Checking the problem further I see its mac address stops being learned by the bridge and the problem is resolved only with a VM reboot.

When I last saw the problem I run brctl showmacs ovirtmgmt and it shows me the VM's mac adress with agening timer 200.19. After the VM reboot I see the same mac with agening timer 0.00.
I don't see it in another environment where the ovirtmgmt is not used for VMs.

Does anyone have any clue about this type of behavior ?

Fernando
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