On existing Debian

Install Proxmox on ready Debian system. Benefits:

• unusual disk setup (i.e. not using ZFS for raid, only generic MD or LVM raid)
• for lazy people: running system with remote access only

Package Repositories Detailed step-by-step instuciton wiki

It is very important (to SSL key generation), that hostname is resolved do IP address of device:

hostname --ip-address
192.168.15.77 # should return your IP address here

echo 'deb http://download.proxmox.com/debian/pve buster pve-no-subscription' > /etc/apt/sources.list.d/pve-no-sub.list

wget http://download.proxmox.com/debian/proxmox-ve-release-6.x.gpg -O /etc/apt/trusted.gpg.d/proxmox-ve-release-6.x.gpg apt-get update apt-get remove network-manager apt-get install ifupdown2 open-iscsi ksmtuned apt-get remove ntp systemctl enable –now systemd-timesyncd apt-get install proxmox-ve apt-get install pve-headers </code>

To avoid GFX issues disable modeset:

/etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="mitigations=off panic=30 nomodeset"

Reboot system. System will boot with default Debian kernel, because Buster Backports kernel is newer than Proxmox one. With dfault Debian kernel there is no ZFS support, and also Docker engine cannot work because of some apparmor issues.

To try to boor PVE kernel once:

/etc/default/grub

GRUB_DEFAULT=saved
# Comment or disable:
# GRUB_SAVEDEFAULT=true

update-grub
# get menu ids:
egrep -i "menuentry '|submenu '" /boot/grub/grub.cfg
# Set grub env using chosen ids. For submenu use '>'
grub-set-default 'gnulinux-simple-21b9a8a1-48e8-4c4d-8420-6c97870f2702'
grub-reboot 'gnulinux-advanced-21b9a8a1-48e8-4c4d-8420-6c97870f2702>gnulinux-5.3.18-3-pve-advanced-21b9a8a1-48e8-4c4d-8420-6c97870f2702'

If everything works well, remove Debian kernel.

apt remove linux-image-amd64 'linux-image-4.19*' 'linux-image-5.4*'
update-grub
grub-set-default 0

Proxmox was installed with incorrect /etc/hosts configuration. After fixing it still shows errors in journal:

pveproxy[26742]: /etc/pve/local/pve-ssl.key: failed to load local private key (key_file or key) at /usr/share/perl5/PVE/APIServer/AnyEvent.pm line 1727.
pveproxy[26743]: /etc/pve/local/pve-ssl.key: failed to load local private key (key_file or key) at /usr/share/perl5/PVE/APIServer/AnyEvent.pm line 1727.

journalctl -u pve-cluster
 
systemd[1]: Stopped The Proxmox VE cluster filesystem.
systemd[1]: Starting The Proxmox VE cluster filesystem...
pmxcfs[2398]: [main] crit: Unable to get local IP address
pmxcfs[2398]: [main] crit: Unable to get local IP address
systemd[1]: pve-cluster.service: Control process exited, code=exited, status=255/EXCEPTION
systemd[1]: pve-cluster.service: Failed with result 'exit-code'.
systemd[1]: Failed to start The Proxmox VE cluster filesystem.

Reason cluster FS on /etc/pve was not started, symlinks to nodes points to nowhere:

/etc/pve# tree
.
├── local -> nodes/host281
├── lxc -> nodes/host281/lxc
├── openvz -> nodes/host281/openvz
└── qemu-server -> nodes/host281/qemu-server

Reboot device

Missing local-zfs.