Re: [libvirt] networking with two hosts

Am 26.02.2009 um 20:26 schrieb Radek Hladik: > Andreas Rittershofer napsal(a): >> My problem is: >> 1.) VM1 running on host A must have network access to VM3 when VM3 is >> running on host B by default _and_ >> 2.) when VM3 is running on host A because host B failed. >> In some of my configurations 1.) worked but 2.) not, in some other >> configurations 2.) worked but 1.) not. >> I must have missed some detail ... > > I do not see the problem. With the bridged scenario every VM has > direct access to the physical network and it is not important on which > host it runs. If the VMs are running on the same host, their ethernet > frames will just "turn around" in the bridge interface and if they are > running on different hosts they will go thru the real ethernet. > > State 1) > A: VM1 > B: VM3 > > Eth. frames will go like this: > VM1->BrA->PhysCardA->Ethernet->PhysCardB->BrB->VM3 > State 2) > > A: VM1+VM3 > B: x > > Eth. frames will go like this: > VM1->BrA->VM3 > NOW I've got it! The errors in my configuration were two different network configurations on host A and on host B - I always thought that the network on host A and the network on host B must have different IP addresses. Now there is only on network configuration for host A _and_ host B and everything is fine! Thank you very much for your help! mfg ar