I've noticed a spike in the reoccuring problem of the network forgetting
the location of virtual machines within the Xen infrastructure. My VMWare Admin
has also seen this occur many times with VMware virtual machines, which
leads me to believe its not an issue with the server side.
The symptoms are networking drops, but just for a particular VM. I've
performed packet captures and it looks like traffic does not even get
sent to the Xen server itself for that VM, nevermind passed into the VM
itself. It doesn't matter if I'm initating traffic from the same subnet
or a different network; traffic doesn't get to the VM. Thus, I think
this is a layer 2 issue. I'm guessing the switches forget the MAC
address location.
My resolution for when this occurs is to migrate the VM to another Xen
server, thus causing the network to relearn its location. This is also
how the other admin fixes this issue with VMware VM's.
Has anyone else experienced this? This seems to occur with VMs that have very low traffic profiles...