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I have a proxmox cluster, that is distributed over two different subnets having two different gateways. In the first subnet VMs get an publicly available static IP address by MAC address mapping. vmbr0 is configured in this first subnet as bridge. KVM is used for virtualization.

Is it possible to keep the IP address for VMs after a live migration to the second subnet? What would be a working configuration for vmbr0 in the second subnet? VLAN, VPN, and IP tunnel are concepts I've thought about, but got no working solution.

Here is a similar case: KVM "live migration finished" detection But I do not want a new IP address. The VM should keep the IP address.

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How do you expect traffic to get routed to/from this server when it's on the wrong subnet?

It sounds like you need to establish 802.1q trunks from your switchgear to all of your cluster nodes. This way, you can have all of your subnets available on all the nodes.

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I had hoped the master could work as an "intermediary" for the slave in the other subnet. And proxmox would have a specific solution for such cases. – Kantan Jul 12 '12 at 20:23
There are already mechanisms in the network layer to handle this (namely 802.1q) - it would be exceedingly difficult for the proxmox folks to provide a workaround that would be applicable in all situations and on all networks. – EEAA Jul 12 '12 at 21:02

To perform a live migration and keep the virtual machine's IP address, both hosts must be on the same subnet.

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