Since I like to image systems I’m testing, here’s the process I use to capture the boot drive of a bare metal system in Proxmox Backup Server. I start by booting into a Debian Live image (the small one without a GUI).

Next, I install Proxmox Backup Client from apt packages:

#Run as root
sudo bash
#Add repo
wget -O /etc/apt/trusted.gpg.d/proxmox-release-bookworm.gpg
echo "deb bookworm main" > /etc/apt/sources.list.d/pbs-client.list

#Install PBS
apt update
apt install proxmox-backup-client -y

After that, I set the environment variables for the backup client (I have a doc I can copy/paste from into my USB KVM):

#Environment variables - these will be your Proxmox Backup user and stuff
export PBS_REPOSITORY=user@realm@dns_name.lan:datastore
export PBS_PASSWORD=api_key
export PBS_FINGERPRINT="fingerprint"

And finaly, run the image itself. The ‘backup-id’ comes across as ‘host’ in PBS, so I name it only once per physical system, and I can add notes later in the PBS UI as to which backup of the dxp4800 this was. Syntax is .img:/dev/disk. I always use root.img for the root disk, and this captures the entire disk, not partitions.

#Backup command
#root.img is the name of the image (stored in the backup), you can add this multiple times for multiple disks
#/dev/nvme0n1 is the disk that will be copied into root.img
#backup-id is the 'host name' as stored in Proxmox Backup Server
proxmox-backup-client backup root.img:/dev/nvme0n1 --backup-id "ugreen-dxp4800"