[SOLVED] Migrate instance from openstack to proxmox with ceph storage backend

[semira uthsala]

Hi all,

We are using openstack for most of our production instances with ceph storage backend. Recently we added additional hardware and setup Proxmox v6 and attached it to the same ceph storage cluster

With the ceph storage integration we tested couple of instance and it works perfectly fine

The only way we tested migration from openstack to Proxmox is extracting qcow image from openstack and import it to the proxmox then launch instance

Is there a way that I can directly point proxmox instance to the existing RBD image on the ceph storage ? This way we can shutdown instance from openstack and point proxmox instance to the same RBD image and launch it on proxmox. Is it possible to do that ?

Or what are the other ways to migrate instances from openstack with minimal downtime

 

[Alwin]

Is there a way that I can directly point proxmox instance to the existing RBD image on the ceph storage ? This way we can shutdown instance from openstack and point proxmox instance to the same RBD image and launch it on proxmox. Is it possible to do that ?

The naming of the RBD images are different. This means, that you will need to rename them on Ceph. See the naming of an existing VM on Proxmox VE. Then you can use qm rescan <vmid> to get the disks as 'unused' disks into an existing configuration.

That said, this is not a standard migration scenario and is not supported by Proxmox support.

Or what are the other ways to migrate instances from openstack with minimal downtime

Export the VM on openstack as OVF and use qm importdisk to get the disk added to an existing VM.

More tips can be found on our wiki.
https://pve.proxmox.com/wiki/Migration_of_servers_to_Proxmox_VE

 

[semira uthsala]

Hi,

Thanks for your answer. I was able to migrate VM using the below steps based on your answer.


1. I created VM on Proxmox with same specs

2. Note down the VM ID of the Proxmox VM ( in my case vm-103)

3. Stop and find the volume ID of the Openstack VM we need to migrate

rbd ls POOL_NAME | grep VOLUME_ID

4. Get a copy of OpenStack VM volume with rbd cp

rbd cp POOL_NAME/OPENSTACK_VOLUME_ID POOL_NAME/vm-103-disk-1

5. In Proxmox node issue the command qm rescan to add the newly copied volume to the VM

qm rescan --vmid 103

6. Add newly found unused disk to the VM using GUI

7. Change the boot order from Proxmox to boot from new volume (vm-103-disk-1)



Also, I tested directly renaming the rbd image and it also works.

I use RHEL 7.x image for testing.