GNS3 is not showing console to the virtualbox virtual machines

You can use ttyS0 settings as kernel boot parameter:

GRUB_CMDLINE_LINUX='console=tty0 console=ttyS0,19200n8'
GRUB_TERMINAL=serial
GRUB_SERIAL_COMMAND="serial --speed=19200 --unit=0 --word=8 --parity=no --stop=1"

then execute update-grub as root:

# update-grub










source:

https://stackoverflow.com/questions/18801036/gns3-is-not-showing-console-to-the-virtualbox-virtual-machines