[libvirt-users] Migrating a LV backed guest

Corey Quinn corey at sequestered.net
Wed Oct 17 04:10:12 UTC 2012

On Oct 16, 2012, at 9:15 PM, Eric Blake <eblake at redhat.com> wrote:

> On 10/16/2012 04:37 AM, Corey Quinn wrote:
>> I have a KVM VM that's backed by a logical volume on local disk.
>> I'd like to copy / move it to an identically configured host.
>> [root at virt2 cquinn]# virsh migrate --copy-storage-all --verbose --persistent  node1.www qemu+ssh://
> Off-hand, that looks right; I just double-checked
> http://libvirt.org/migration.html to make sure that it looks like a
> valid native migration usage.  But do be aware that --copy-storage-all
> is poorly tested, and also that it currently requires you to pre-create
> a destination file by the same name (there has been talk about patching
> libvirt to auto-create the files, but that patch is still in the work,
> and for back-compat reasons, it would require you to pass another option).

Hmm, then what's the "proper" method to copy the VM's backend logical volume?  At the moment I'm trying to copy a template VM (used for girt-clone) rather than having to build one of them per host-- that's tedious and an obnoxious source of variance.

I'm not opposed to dding it via netcat, but the last time I tried this there was something "off" enough that the VM hung during boot.

>> error: Unable to read from monitor: Connection reset by peer
> This most likely means that qemu on the receiving end died quite early;
> perhaps looking at /var/log/libvirt/qemu/node1.www.log will give you
> more clues why.

char device redirected to /dev/pts/2
inet_listen_opts: bind(ipv4,,5901): Cannot assign requested address
inet_listen_opts: FAILED

This is on the destination node, but is assigned to the source host, not the destination.  Does this need to be an IP that's shared between the two hosts?  Frankly, I don't much care if the vnc display 

Additionally, the migrate refuses to start unless the VM is running, but that's far from a requirement from my perspective-- not sure if that's a bug or a feature.

-- Corey

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