[Bridge] Bridging vSwitches in VMwares ESXi

Ryan King ryank at globaldial.com
Tue Apr 6 20:21:07 PDT 2010


> -----Original Message-----
> From: bridge-bounces at lists.linux-foundation.org [mailto:bridge-
> bounces at lists.linux-foundation.org] On Behalf Of Robert LeBlanc
> Sent: Wednesday, 7 April 2010 11:02 AM
> To: Ryan Whelan
> Cc: bridge at lists.linux-foundation.org
> Subject: Re: [Bridge] Bridging vSwitches in VMwares ESXi
> 
> On Tue, Apr 6, 2010 at 8:41 PM, Ryan Whelan <ryan.whelan at tbamerica.com>
> wrote:
> > oh good- glad to find out im not crazy. we do have 2 pNICs in the
> external
> > facing vSwitch.  Even when setting them as active/passive, its still
> an
> > issue.
> >
> > so its a confirmed issue with vmware- do they have any intention on
> > correcting it? do we know?
> >
> 
> Yes as long as the pNIC is attached, even if in standby mode it causes
> a problem.
> 
> It is an issue, but they won't fix it for two reasons. 1. They will
> never create a bridge between two vSwitches/VLANs, and 2. a fix would
> introduce more overhead and reduce flexibility and since they adhere
> to #1, it doesn't make sense. The flexibility they lose is multiple
> pNICs to one or more switches without having to have any trunking
> protocols.
> 
> You can get around the problem by buying the Cisco Nexus virtual
> switch, it's a real layer 3 switch, but it's a pricy option.
> 
> If you want a bridge in a VM, then only pNIC per switch (no
> redundancy). The other option, try to make the bridge a router
> instead. For us we wanted a transparent firewall, so it was easy to
> change the configuration to proxyarp for a transparent router instead.
> 

Just to clarify our setup:

The physical server has 4 physical nics.  vswitch1 uses 2 pnics in
active/active.  vswitch2 uses 2 pnics in active/active.

The VM (running openvpn) has a bridge with one vnic on vswitch1 and one vnic
on vswitch2.  Since moving the 2nd interface to vswitch2, I have not
experienced this issue any more (ie: previously, both vnics were on vswitch1
- this was where we saw this issue).

Ryan King





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