Virtualization
Create Virtual Machines (VMs), clone, run, test, study and use them.
- Oracle VirtualBox @Windows10Pro
- Cloning the machines and post-install for Oracle Linux v9
- Adding more space to virtual machine by adding new disk and expanding using LVM
- Proxmox Virtual Environment (PVE)
- Check list to check in BIOS for remote machine
Oracle VirtualBox @Windows10Pro
Cloning the machines and post-install for Oracle Linux v9
At the moment of writing, on 2025-07-18, my VirtualBox is v7.1.6.
Open VirtualBox, find the source machine, click once to select
It is possible to either use menu: Snapshot> Clone
Or click on [Clone] icon with a sheep:
Or right-click on virtual machine itself:
of press C-S-c (CTRL+SHIFT+c) or, from the list: C-o (CTRL+o)
Give machine a new name, check location and remember to choose "Generate new MAC for adapters". Your network infra will be happy to see healthy traffic and route it properly.
When machne is cloned, let's start it:
Post-cloning precedures
All commands executed in the elevated shell
sudo su
Change hostname
hostnamectl hostname lt58dox1
During cloning the machines, change physical ID and MAC address in the hypervisor (sometimes, it will not do it automatically in VirtualBox, proxmox and others).
When machines are cloned, 'machine ID':
cat /etc/machine-id
rm -f /etc/machine-id
systemd-machine-id-setup
systemd-machine-id-setup --commit --print
SSH server's keys need to be re-generated to be seen as different machines
rm -rf /etc/ssh/ssh_host_*
ssh-keygen -A
ls -la /etc/ssh/ssh_host_*
And finally perform reboot
shutdown -r now
As there will be new MAC assigned, check for new IP addresses:
ip -br a
Adding more space to virtual machine by adding new disk and expanding using LVM
Daily task, which comes as daily routing, to extend the disk space:
Switch off the machine
Open VM properties in Oracle VirtualBox Manager, Storage,
Click [Create]
Name the disk accordingly to be consistent with other drives. Ensure that disk is saved nearby the VM itself. In my case, I am extending root partition for 50 GB.
After new disk is created, choose it double-clicking it.
Should end by seeing new disk in the virtual machine properties under 'Storage' list, attached to proper controller, 'SATA' - in my case.
Confirm with [OK]
Power on the machine
List disks with. New disk should be visible.
lsblk
Follow LVM Disk Extension guide to finalize extension.
Proxmox Virtual Environment (PVE)
Enabling no-subscription repositories
Prepare
Launch shell from hypervisor
This should provide root shell (priviledged access), if not elevate
sudo su
Ensure Internet connectivity from hypervisor itself (it can resolve and ping the source)
ping download.proxmox.com
apt update
apt install tmux
tmux
On Debian v13 (trixie)
mv /etc/apt/sources.list.d/pve-enterprise.sources /root
mv /etc/apt/sources.list.d/ceph.sources /root
Which version of Debian is running?
hostnamectl | grep -i debian
Create new file
nano /etc/apt/sources.list.d/pve-no-subscription.list
repos
# for Debian GNU/Linux 13 (trixie)
deb http://download.proxmox.com/debian/pve trixie pve-no-subscription
close editor, confirm changes (save)
CTRL+X, y
Adjust Debian repos
nano /etc/apt/sources.list.d/debian.sources
verify repos
#
# for Debian GNU/Linux 13 (trixie)
#
Types: deb
URIs: http://deb.debian.org/debian/
Suites: trixie trixie-updates
Components: main contrib non-free-firmware
Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg
Types: deb
URIs: http://security.debian.org/debian-security/
Suites: trixie-security
Components: main contrib non-free-firmware
Signed-By: /usr/share/keyrings/debian-archive-keyring.gpg
Close editor, save
CTRL+X, y
Verify that repositories declared properly
apt policy
another one:
Do APT update
apt update
List packages ready for update, most important that there are new packages from PVE repo.
apt list --upgradable
another one:
Perform upgrade (when needed)
apt upgrade
the another one
Proxmox VE root pass reset (break the glass)
If you forgot the password, it is possible to change passowrd from the machine's console (physical access required):
Reset root password inside rescue shell:
Boot the server.
In GRUB find Proxmox VE GNU/Linux and press e to edit boot entry.
Config file will open, Find the line starting with linux (to load Linux kernel)
Add at the end of the that same line (not to the end of the file):
init=/bin/bash
Boot with
CTRL+X
Remount filesystem in read-write mode:
mount -o remount,rw /
Check the disk (optionally) to verify the disk is re-mounted:
df -hT
Change root's password:
passwd
Reboot
reboot -f
Login with new pass, usually to port 8006
https://nn.nn.nn.nn:8006/
and press [Login]
Change password (top-right, under username and 'Password')
Create admins user group
Create another admin user, add to admin user group created above
Define user's password
Add group permissions
Define permissions
Check list to check in BIOS for remote machine
| Risk | Mitigation | |
| Remote switch off | power on schedule: everyday, 06h00 | |
| Electricity flaps, flashes | On AC recovery: Power ON | |
| Keyboard disconnected | disable [ ] enable keyboard error detection | |
| Display disconnected | Attach HDMI or DP dummy stick to emulate display. | |