Proxmox Copy & Paste

One annoying issue is the sometimes working and sometimes not working Copy & Paste.

Add a Serial port

We need to add serial0 to the virtual machine, there are two ways to do it:

If you want Copy/Paste, do:

• VM → Hardware → hit Add → select Serial Port
• VM → Hardware → Display → Edit Display: Graphic card: Serial terminal 0

Or the by

• Use the following command to add the serial0 -port
• qm set [vmid] -serial0 socket
• Use the Proxmox VE web GUI
  Go to Datacenter → node name/cluster name → VM ID → Hardware → hit Add → select Serial Port
• VM → Hardware → Display → Edit Display: Graphic card: Serial terminal 0

Old way for GRUB-based

For systems based on Debian and RHEL

Depending on your VM OS

• Debian/Ubuntu/Kali Linux etc.: update-grub
• RHEL/CentOS/Fedora: grub2-mkconfig --output=/boot/grub2/grub.cfg
• NOT Alpine with Grub, see the Alpine section!

Restart the VM

Restart the virtual machine, when it’s booted, launch xterm.js, Press Enter multiple times, we now should have connected to the virtual machine with xterm.js successfully

Modify GRUB

Edit /etc/default/grub -file as root or use sudo by running this command:

sudo sh -c 'echo 'GRUB_CMDLINE_LINUX="quiet console=tty0 console=ttyS0,115200"' >> /etc/default/grub'

Or you can edit the file manually nano /etc/default/grub,

Find the line with “GRUB_CMDLINE_LINUX”

Add the necessary part: console=tty0 console=ttyS0,115200

Update GRUB

Depending on your VM OS

• Debian/Ubuntu/Kali Linux etc.: update-grub
• RHEL/CentOS/Fedora: grub2-mkconfig --output=/boot/grub2/grub.cfg

Restart the VM

Restart the virtual machine, when it’s booted, launch xterm.js, Press Enter multiple times, we now should have connected to the virtual machine with xterm.js successfully

Alpine

We need agetty, and have it running.

• Install by doas apk add agetty
  • and doas rc-update addd agetty default
• Status: doas rc-service agetty status
• Start:
  • doas rc-service agetty start
  • doas rc-service agetty.ttyS0 start

Edit /etc/inittab

Start by editing doas vi /etc/inittab and look for lines like tty1::respawn:/sbin/getty 38400 tty1. Un comment or add serial console line

ttyS0::respawn:/sbin/getty -L ttyS0 115200 vt100

Tell init to reload inittab

Finalize it by sudo kill -HUP 1. No reboot needed.

Edit extlinux.conf

We will need to append to the file: doas vi /boot/extlinux.cfg.

• Look for or add the line starting with APPEND root=
  • append console=tty0 console=ttyS0,115200 to the end.

Ensure kernel console output goes to serial – Critical

Without this, login may succeed, but you won’t see it.

Check it by: cat /proc/cmdline.
You should see something like: console=ttyS0,115200.
If not, add it doas vi /proc/cmdline.

GRUB-based Alpine

Edit: doas vi /etc/default/grub and ensure you have GRUB_CMDLINE_LINUX="console=tty0 console=ttyS0,115200"

Then just create a config and boot

• doas grub-mkconfig -o /boot/grub/grub.cfg
• doas reboot
  

Proxmox

In Proxmox, the VM must have a serial device. Add one by

• Hardware → Add → Serial Port
• Use socket
• You might like to set Display → Serial terminal (Option)

Otherwise, Alpine can be perfectly configured and still show nothing.

FreeBSD

FreeBSD, is closer to the Alpine philosophically:

• no systemd,
• no services for getty on-demand – it’s done via ttys and loader/kernel hints.

Here is the canonical, correct FreeBSD way.

Enable serial login /etc/ttys – the key part

Edit: sudo vi /etc/ttys, you’ll see lines like:

• ttyv0 "/usr/libexec/getty Pc" xterm onifexists secure

Add or modify the serial line:

• ttyu0 "/usr/libexec/getty std.115200" vt100 onifexists secure

This alone is the equivalent of enable + start. No reboot required for login availability.

Enable serial console output (boot messages)

For temporarily running sudo vidcontrol -f /dev/ttyu0. Useful for testing.

Permanently — loader configuration

Edit: sudo vi /boot/loader.conf and add console="comconsole,vidconsole" comconsole_speed="115200". This ensures that bootloader & kernel output go to serial.

Headless systems – serial only

If you want no VGA at all: /boot/loader.conf console="comconsole".
Optional but common on servers.

On a VM – Proxmox / QEMU

Make sure:

• A serial device is actually attached
• Speed matches 115200
• VM console is connected to COM1

Otherwise, FreeBSD will be perfectly configured and still appear dead.

Verify after boot

dmesg | grep ttyu

ps -ax | grep getty

cat /proc/cmdline   # (does not exist on FreeBSD — absence is expected)

One-line takeaway

Mapping table