Install Proxmox 7 on Debian 12

Install a standard Debian Bookworm, for details consider the Debian installation guide, and configure a static IP.

Note: The Debian installer performs network configuration by IPv6 autoconfiguration and DHCP by default, if available. To force manual network configuration in the UEFI installer, press E and add netcfg/disable_autoconfig=true to the linux command line. For the BIOS installer, select the Help entry and start the installation by typing installgui netcfg/disable_autoconfig=true. For further details, see the Debian installer documentation.

It is recommended to only install the “standard system utilities” and “SSH server” package selection, as Proxmox VE brings its own packages for QEMU and LXC. A desktop environment is not necessary.

Add an /etc/hosts entry for your IP address

The hostname of your machine must be resolvable via /etc/hosts. This means that in /etc/hosts you need one of the following entries for your hostname:

1 IPv4 or
1 IPv6 or
1 IPv4 and 1 IPv6

Note: This also means removing the address 127.0.1.1 that might be present as default. For instance, if your IP address is 192.168.15.77, and your hostname prox4m1, then your /etc/hosts file could look like:

127.0.0.1 localhost
192.168.15.77 prox4m1.proxmox.com prox4m1

# The following lines are desirable for IPv6 capable hosts
::1 localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

You can test if your setup is ok using the hostname command:

hostname --ip-address

192.168.15.77 # should return your IP address here

Install Proxmox VE

Add the Proxmox VE repository:

echo "deb [arch=amd64] http://download.proxmox.com/debian/pve bookworm pve-no-subscription" > /etc/apt/sources.list.d/pve-install-repo.list

Add the Proxmox VE repository key as root (or use sudo):

wget https://enterprise.proxmox.com/debian/proxmox-release-bookworm.gpg -O /etc/apt/trusted.gpg.d/proxmox-release-bookworm.gpg 
# verify
sha512sum /etc/apt/trusted.gpg.d/proxmox-release-bookworm.gpg 
7da6fe34168adc6e479327ba517796d4702fa2f8b4f0a9833f5ea6e6b48f6507a6da403a274fe201595edc86a84463d50383d07f64bdde2e3658108db7d6dc87 /etc/apt/trusted.gpg.d/proxmox-release-bookworm.gpg

Update your repository and system by running:

apt update && apt full-upgrade

Install the Proxmox VE Kernel

First you need to install and boot the Proxmox VE kernel, as some packages depend on specific kernel compile flags to be set or feature extensions (e.g., for apparmor) to be available.

apt install pve-kernel-6.2
systemctl reboot

Install the Proxmox VE packages

apt install proxmox-ve postfix open-iscsi

Configure packages which require user input on installation according to your needs. If you have a mail server in your network, you should configure postfix as a satellite system. Your existing mail server will then be the relay host which will route the emails sent by Proxmox VE to their final recipient.

If you don’t know what to enter here, choose local only and leave the system name as is.

Remove the Debian Kernel

Proxmox VE ships its own kernel and keeping the Debian default kernel can lead to trouble on upgrades, for example, with Debian point releases. Therefore, you must remove the default Debian kernel:

apt remove linux-image-amd64 'linux-image-6.1*'

Update and check grub2 config by running:

update-grub

Recommended: Remove the os-prober Package

The os-prober package scans all the partitions of your host to create dual-boot GRUB entries. But the scanned partitions can also include those assigned to virtual machines, which one doesn’t want to add as boot entry.

If you didn’t install Proxmox VE as dual boot beside another OS, you can safely remove the os-prober package:

apt remove os-prober

Connect to the Proxmox VE web interface

Connect to the admin web interface (https://your-ip-address:8006). If you have a fresh install and have not added any users yet, you should select PAM authentication realm and login with root user account.

Create a Linux Bridge

Create a Linux Bridge called vmbr0, and add your first network interface to it. The recommended default configuration can be adapted from the example given in the documentation. See the default configuration using a bridge.

Src:
https://pve.proxmox.com/wiki/Install_Proxmox_VE_on_Debian_12_Bookworm