Open Stack

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 
https://github.com/os-migrate/os-migrate

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