Logical Volume migration to a New Openstack environment

Sean Mooney smooney at redhat.com
Wed Jan 5 11:14:32 UTC 2022

On Wed, 2022-01-05 at 16:24 +0530, KK CHN wrote:
> List,
> I am in need to migrate a Virtual machine ( running in an old OpenStack
> environment with only one controller).  This VM has its own disk file +  a
> logical volume attached to it with application data on it.   Only Cinder
> backend( No rbd/ceph backend configured ) for this environment.
> Now I am migrating this Virtual machine to another OpenStack(ussuri  with
> three controllers, three compute nodes and three storage nodes) environment
> with ceph/rbd backend.
> I am able to  export the VM with its disk file and  import it to the other
> openstack environment and able to boot the machine.
> But  How to export the attached logical volume from the  old VM and attach
> to the  VM  in the other environment ?
if its just a singel vm you can convert teh volume to an image then download and upload it to the
the new cloud and finally create a volume form that image.

if you have to do this wiht more then one vm you might want to look at 

which is being created to automate migrating workloads betwen clouds
it will copy the volume in a more efficent way by directly copying the data form the source could to the destination witout creating images.

> what is the  methodology to follow to  export this logical volume in the
> old openstack VM   and import to the new VM running in the other openstack
> environment ?
the manual procedure is to convert it to a glance image and download and upload it. that only works if glance is not useing volume backed images.
os-migrate will create a migration vm in each cloud, detach the volume from its current vm on the source cloud then attach it to the migration vm
on the dest cloud it will create a new empty volume and attch it to the might vm.
then it basicly rsyncs the datat from one migration vm to the other.

> kindly share  your suggestions/expertise to perform this
> Thanks in advance for your valuable guidance.
> Krish

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