[libvirt-users] Canging bridge names on live migration

Laine Stump laine at laine.org
Wed Jun 3 14:59:25 UTC 2015


On 06/03/2015 07:22 AM, seitan wrote:
> Hello,
> i wonder, if there's a possibility to change a name of a shared interface in
> virtual machine config, while doing migration.
> The problem is:
> hypervisor1 (source) uses shared interface name  "br0".
> hypervisor2 (target) uses shared interface name "br500".
> Live migration fails, because target hypervisor does not have "br0" interface.

The simplest method of doing what you need:

Instead of using "<interface type='bridge'>",

1) create an "unmanaged virtual network" with the same name on both hosts

On source host:

    <network>
      <name>bridge-net</name>
      <forward mode='bridge'/>
      <bridge name='br0'/>
    </network>

On destination host:

    <network>
      <name>bridge-net</name>
      <forward mode='bridge'/>
      <bridge name='br500'/>
    </network>

(put the above into files, then use "virsh net-define $file && virsh
net-autostart bridge-net && virsh net-start bridge-net" to activate the
new networks)

2) Change the interface definition in your guests to:

      <interface type='network'>
        <source network='bridge-net'/>
        ....
        [whatever else was already there]
      </interface>

The guest XML now doesn't need to change during migration, so you can
avoid the need to modify it with a migration hook (as suggested in the
other response to your question)




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