Proxmox on wporter.org

Creating a cloud-init VM template for AlmaLinux 10 on Proxmox VE

Thu, 26 Feb 2026 22:30:00 +0000

Just a quick example.

vmid=9001
image_name="AlmaLinux-10-GenericCloud-latest.x86_64.qcow2"
storage="local-lvm"

wget https://repo.almalinux.org/almalinux/10/cloud/x86_64/images/AlmaLinux-10-GenericCloud-latest.x86_64.qcow2 -O $image_name

qemu-img resize $image_name 32G

qm create $vmid --name "almalinux-10-genericcloud" --ostype l26 \
  --memory 2048 \
	--agent 1 \
	--bios ovmf --machine q35 --efidisk0 "$storage":0,pre-enrolled-keys=0 \
	--cpu host --socket 1 --cores 2 \
	--net0 virtio,bridge=bridge0

qm set $vmid --sata0 local-lvm:cloudinit

qm importdisk $vmid $image_name $storage

qm set $vmid --scsihw virtio-scsi-single --scsi0 local-lvm:vm-${vmid}-disk-2,discard=on,cache=writeback,iothread=1,ssd=1

qm set $vmid --boot order=scsi0

qm template $vmid

Migrating Libvirt VMs to Proxmox VE by importing qcow2 disks to Ceph

Sun, 22 Feb 2026 23:00:00 +0000

I’m migrating from a Libvirt hypervisor (AlmaLinux 10) to Proxmox VE.

In my case, my images are backed by a cloud-init template:

[root@3060t0 ~]# qemu-img info --backing-chain /var/lib/libvirt/images/UniFi_OS.qcow2 
image: /var/lib/libvirt/images/UniFi_OS.qcow2
file format: qcow2
virtual size: 32 GiB (34359738368 bytes)
disk size: 5.09 GiB
cluster_size: 65536
backing file: /srv/iso/AlmaLinux-10-GenericCloud-10.0-20250528.0.x86_64.qcow2
backing file format: qcow2
Format specific information:
    compat: 1.1
    compression type: zlib
    lazy refcounts: true
    refcount bits: 16
    corrupt: false
    extended l2: false
Child node '/file':
    filename: /var/lib/libvirt/images/UniFi_OS.qcow2
    protocol type: file
    file length: 6.51 GiB (6987579392 bytes)
    disk size: 5.09 GiB

image: /srv/iso/AlmaLinux-10-GenericCloud-10.0-20250528.0.x86_64.qcow2
file format: qcow2
virtual size: 10 GiB (10737418240 bytes)
disk size: 439 MiB
cluster_size: 65536
Format specific information:
    compat: 1.1
    compression type: zlib
    lazy refcounts: false
    refcount bits: 16
    corrupt: false
    extended l2: false
Child node '/file':
    filename: /srv/iso/AlmaLinux-10-GenericCloud-10.0-20250528.0.x86_64.qcow2
    protocol type: file
    file length: 439 MiB (460062720 bytes)
    disk size: 439 MiB

So, before I move the VMs off this host (with the backing file on it) I had to rebase them (consolidate the backing file and changes to a new QCOW). This can be done by “converting” the current VM disk with qemu-img.

PVE/Ceph hyperconverged cluster build/Ceph performance tuning

Sun, 22 Feb 2026 22:00:00 +0000

Introduction

This is a continuation of (and hopefully the final rebuild for) my “2025 Q4” cluster build project (yeah, I went a little past my deadline there).

Long story short, I’ve been looking to eliminate single points of failure in my infrastructure (at least, where they’re easy to fix), so I wound up with three HP Z2 G4 SFF workstations (LGA 1151) and started trying to build a Proxmox (as I’m now responsible for supporting it professionally and do not have the time to figure out the perfect hypervisor That Is Not Proxmox) cluster out of them.

Failing to build a Proxmox + LINSTOR (DRBD) HCI cluster (ft. RDMA and ewaste!)

Mon, 02 Feb 2026 22:00:00 +0000

Introduction

I had a machine go down the other day. It was my sole “production” hypervisor (an old crappy Optiplex) running all my stuff. Yes, my redundant DNS… on one machine.

So I set about fixing it. I did some reading on distributed storage (because who do you think I am? I’m not going to waste machines on making my own SAN.. at least, I won’t if I have to pay for power), scrounged through the drawers for RAM and SSDs, ordered some modest hardware, and here we are. This is (supposedly) my new production hypervisor cluster!

Snippet: Disable max vCPUs eq phys. threads restriction in Proxmox VE 8.3

Wed, 27 Nov 2024 12:34:56 +0000

Source:

jknight comment on Proxmox forums

Problem:

Needed to assign more than 64 threads to a VM for testing (just needed more than 64 threads, don’t care about performance or lack of it.)

This was helpful and took a little bit of digging to find.

Solution:

Open /usr/share/perl5/PVE/QemuServer.pm with your favorite text editor.

Remove lines 3772 - 3776 (if you’re /ing around afterwards or have an otherwise modified config file, this will be right after line 3770: my $vcpus = $conf->{vcpus} ? $conf->{vcpus} : maxcpus;)