# При установке proxmox 8 на debian 12 после команд получил ошибку:
 
echo "deb [arch=amd64] http://download.proxmox.com/debian/pve bookworm pve-no-subscription" > /etc/apt/sources.list.d/pve-install-repo.list
 
apt update && apt full-upgrade
 
 
W: GPG error: http://download.proxmox.com/debian/pve bookworm InRelease: 
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1140AF8F639E0C39
E: The repository 'http://download.proxmox.com/debian/pve bookworm InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.                                                                                                                                              
N: See apt-secure(8) manpage for repository creation and user configuration details.

Установил сразу же gnupg2, подписал ключ и установил всё.

# Установил gnupg2
apt install gnupg2
# подписал ключ 1140AF8F639E0C39
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 1140AF8F639E0C39
# обновился
apt update && apt full-upgrade
# накатил ядро proxmox 8
apt install pve-kernel-6.2
# перезагрузка в ядро proxmox
systemctl reboot