Adventures in upgrading Proxmox
16 comments
·November 19, 2025generalizations
speed_spread
Lesson 1: clusters should have an odd number of nodes.
dang
Related ongoing thread:
Proxmox virtual environment 9.1 available - https://news.ycombinator.com/item?id=45980005 - Nov 2025 (56 comments)
Jeff-Collins
"Very helpful tips for a smooth Proxmox upgrade!"
"Clear and practical steps—thanks for sharing!"
"This guide is a lifesaver for sysadmins upgrading Proxmox.
null
throw0101c
See also "Upgrade from 8 to 9":
* https://pve.proxmox.com/wiki/Upgrade_from_8_to_9
And "Known Issues & Breaking Changes (9.1)":
zer00eyz
> Running docker inside LXC is weird.
Knowing when to use a vm and when to use a container is sometimes an opaque problem.
This is one of those cases where a VM is a much better choice.
evanjrowley
I can't speak for the author, but they said they have a Coral TPU passed into the LXC & container, which I also have on my Proxmox setup for Frigate NVR.
Depending on your hardware platform, there could be valid reasons why you wouldn't want to run Frigate NVR in a VM. Frigate NVR it works best when it can leverage the GPU for video transcoding and TPU for object detection. If you pass the GPU to the VM, then the Proxmox host no longer has video output (without a secondary GPU).
Unless you have an Intel Arc iGPU, Intel Arc B50/B60, or fancy server GPU, you won't have SR-IOV on your system, and that means you have to pass the entire GPU into the VM. This is a non-starter for systems where there is no extra PCIe slot for a graphics card, such as the many power-efficient Intel N100 systems that do a good job running Frigate.
The reason why you'd put Docker into LXC is that's the best supported way to get docker engine working on Proxmox without a VM. You'd want to do it on Proxmox because it brings other benefits like a familiar interface, clustering, Proxmox Backup Server, and a great community. You'd want to run Frigate NVR within Docker because it is the best supported way to run it.
At least, this was the case in Proxmox 8. I haven't checked what advancements in Proxmox 9 may have changed this.
roger_
I have Frigate and a Coral USB running happily in a VM on an N97. GPU pass through is slightly annoying (need to use a custom ROM from here: https://github.com/LongQT-sea/intel-igpu-passthru). I think SRIOV works but haven’t tried. And Coral only works in USB3 mode if you pass the whole PCIe controller.
itopaloglu83
Proxmox FAQ calls running Docker on LXC a tech preview and “kind of” recommends VMs. At the very bottom of the page.
https://pve.proxmox.com/wiki/FAQ
> While it can be convenient to run “Application Containers” directly as Proxmox Containers, doing so is currently a tech preview. For use cases requiring container orchestration or live migration, it is still recommended to run them inside a Proxmox QEMU virtual machine.
0x1ch
The way I understand it is that Docker with LXC allows for compute / resource sharing, where as dedicated VMs will will require passing through the entire discrete GPU. So, the VMs require a total passthrough of those Zigbees, container wouldn't?
I'm not exactly sure how the outcome would have changed here though.
selectodude
Am I crazy or is converting a dockerfile into LXC something that should be possible?
null
mzsl
In the new Proxmox VE 9.1 release this should be possible, from the changelog:
> OCI images can now be uploaded manually or downloaded from image registries, and then be used as templates for LXC containers.
poisonborz
This seems like a niche issue, running Docker in LXC for years with dozens of images without a problem.
evanjrowley
I ran into the same issue over the weekend. The end-goal for my Proxmox setup is basically the same deployment you have. It's good to see the issue was addressed quickly by the community.
> As an aside... Because one node didn't start, and my Proxmox cluster has only two nodes, it can't reach quorum, meaning I can't really make any changes to my other node, and I can't start any containers that are stopped. I've recently added another Zigbee dongle, that supports Thread, and it happens to share same VID:PID combo as the old dongle, so due to how these were mapped into guest OS, all my light switches stopped working. I had to fix the issue fast.
Lesson in here somewhere. Something about about a toaster representing the local intelligence maxima?