I think the main quirk to succeed with such migration would be clear understanding of what you are doing, what OpenStack actually is and what options you have on the table, which might not be a straightforward process, though, at the end of the day it should be quite rewarding:) On Wed, 16 Jul 2025, 23:06 Dmitriy Rabotyagov, <noonedeadpunk@gmail.com> wrote:
Generally it would be recommend to actually reset up your hypervisors, as OpenStack Nova assumes having exclusive access to librit/qemu.
So you would pretty much to re-create your VMs through the API to ensure they will be managed from it in the future.
I guess in general it might be possible to accomplish such migration on per-node basis, by doing something similar to offline migration of VMs. It might be not the cleanest process, but should be doable from my perspective.
Also shared storage is not a requirement per say, you still can have an OpenStack setup with local store. Moreover, most of the providers have local storage anyway to provide low latency/high throughput workloads (like databases), so this is totally supported to have a local storage.
On Wed, 16 Jul 2025, 23:00 Leroy Tennison, <leroy.tennison@verizon.net> wrote:
What I was hoping to do was get all our hypervisors managed by OpenStack but no OpenStack environment exists yet, is that possible without destroying (meaning tear down and rebuild) the hypervisors? The plan would be to get everything OpenStack-managed then start moving VMs.
And right now we do not have shared storage. This environment started out with a few hypervisors in some cases attached to Synology nas units with as low as 100Mbit NICs. It has grown and morphed since then but no SAN has been added. I realize this means a live migration will take time and that's acceptable as long as the cutover is brief. I understand the effort will be significant but for a potential of 140+ VMs, it's worth it.
On Wednesday, July 16, 2025 at 03:13:21 PM CDT, John van Ommen < john.vanommen@gmail.com> wrote:
Based on your description, it sounds like you are trying to do a live migration from an existing Ubuntu hypervisor to an OpenStack compute node that doesn't exist yet?
Unfortunately, that's a tremendous amount of work for twenty five virtual machines.
Doing a live migration from an OpenStack compute node to another OpenStack compute node managed by the same OpenStack Control Plane is possible. The reason it's possible is because when you have shared storage, the data itself doesn't have to move; you just have to tell the control plane to instantiate the VM on the new Compute Node, and cease using the old Compute Node. (This is part of the process of upgrading OpenStack; we migrate off the old and onto the new.)
But once you introduce a hypervisor that's NOT managed by OpenStack, live migration becomes significantly more complex.
Anecdotally, there were quite a few 'hybrid cloud solutions' that were popular ten years ago, which attempted to provide a single pane of glass for multiple clouds running competing technologies. Many of those products have 'gaps' in their functionality now, because the upstream APIs changed.
An example of this is Red Hat Cloudforms. It supported OpenStack and Red Hat Enterprise Virtualization, but removed support for AWS because the upstream API on Amazon's end, it changed.
https://github.com/orgs/ManageIQ/discussions/22343
That last paragraph is based on my personal opinion and doesn't represent my employer. Folks from Red Hat certainly know more about the long term strategy for their products than I do, so please consider this when evaluating my statement.
First of all, thank you so much for your response, I certainly appreciate it. I'm glad to answer your questions about our situation:
We are not currently using OpenStack or any other "multiple hypervisor management" solution.
Yes, we already have between 15-20 hypervisors (running various releases of Ubuntu LTS) with KVM/QUMU installed managing from 4 (oldest hardware) to 21 (newest hardware) VMs.
The only issue we're facing is hypervisor OS upgrade - we've discovered
On Wed, Jul 16, 2025 at 12:54 PM Leroy Tennison < leroy.tennison@verizon.net> wrote: that the upgrade process ("do-release-upgrade" for Ubuntu) has significant risks and therefore don't want any running VMs on the hypervisor while we're doing its OS upgrade.
Right now "moving a VM elsewhere" means shutting it down, copying the
image (which uses local hypervisor storage) to a different hypervisor (which can take a significant part of an hour), defining the VM there, starting it up and confirming functionality. With only a few VMs this is time and labor consuming but "do-able", with as many VMs as are running on the newest hardware this is becoming prohibitive.
We have the capacity to be able to move a single hypervisor's VMs
elsewhere. The network is all local (no WAN links) and assume 1Gbit speed (but not higher). The VM images are between roughly 30GB to 200GB. We can determine if a target hypervisor has adequate CPU/RAM/DASD for an additional VM. It's just the effort to "execute" the move.
The fundamental problem is that a number of VMs are Internet-facing
with potential 7x24 hour access requiring notification/coordination with affected external parties before moving the VM to another hypervisor.
We are looking for a solution where we can keep our current
infrastructure (and add a management solution to it) and a VM can remain running while it is being moved to a different hypervisor with the cut over process being brief. The VM's (static) IP and MAC address need to remain the same. If the solution could remove the configuration/image of the VM from it's former location that would be desirable but not necessary. This is the only solution we are looking to implement.
And, again, thank you for any input. Feel free to ask additional
questions.
On Wednesday, July 16, 2025 at 01:04:00 AM CDT, Joel McLean <
joel.mclean@micron21.com> wrote:
G'day Leroy,
OpenStack isn't a hypervisor itself, but more a collection of projects
that can manage hypervisors and the compute workload that runs on them, among other things.
If you have running hypervisors with workload already - as you
mentioned, QEMU/KVM - migrating that workload to an OpenStack platform would require that platform to have hypervisors; which are generally also QEMU/KVM, although they do not have to be.
To give you the right information, we'll want to understand better what
* It sounds like you have an existing workload on QEMU/KVM hypervisors. Why are you considering moving it? * What aspects of Openstack do you actually need? OS is a pretty big
it is you're trying to do: platform, and has a lot of features and benefits, but you pay for that with the overhead of having to manage the OpenStack platform.
* You mentioned that you had looked at ProxMox (PVE) but were worried about it's requirement for centralised storage and fast networking; I can assure you that if you can run OpenStack, you're going to be more than capable of running PVE.
Alternatively, if I have misunderstood your question, and you already have a running OpenStack, and you just want to know how to live-migrate a VM from one hypervisor host to another hypervisor host within the aggregate/availability zone? You can achieve this with a command like : openstack --os-compute-api-version 2.30 server migrate --live-migration --host {target-host-name} {instance-uuid}
Give us a full write up - what have you got, what are you trying to do, what have you tried, why isn't it working? Maybe then we'll be able to help!
Kind Regards,
Joel McLean – Micron21 Pty Ltd
-----Original Message----- From: Leroy Tennison <leroy.tennison@verizon.net> Sent: Wednesday, 16 July 2025 3:09 PM To: openstack-discuss@lists.openstack.org Subject: [ops] Very basic newby questions
I am looking for a solution to automatically move (upon request) running VMs from one hypervisor to another. The current hypervisors are KVM/QEMU. Just looking at the documentation I am becoming overwhelmed.
Questions (A URL which directly addresses the question is quite acceptable):
Does OpenStack work with existing hypervisors or would existing hypervisors have to be "converted" (somehow) to OpenStack?
If it can be used with existing hypervisors, is there a how-to for this specific task (I understand that OpenStack can do many things).
If OpenStack can't be used with existing hypervisors, are you aware of solutions for this need? I have looked at ProxMox but it appears to want centralized storage and very fast networks which doesn't match the environment.
Thank you for your help.