This article will describe changing GRUB2 and Linux to serial console. This is not for desktop environment but embedded system and virtual machine environment.
Table of Contents
1 /etc/default/grub
Change /etc/default/grub as below.
- Change GRUB terminal to console and ttyS0. This will provide one GRUB to a monitor display and serial console.
- Change linux kernel console to tty1 and ttyS0. This setting will be taken over to userland, and there will be two login prompt for tty1 and ttyS0.
$ cat /etc/default/grub GRUB_DEFAULT=0 GRUB_TIMEOUT=1 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` GRUB_CMDLINE_LINUX_DEFAULT="" GRUB_CMDLINE_LINUX="console=tty1 console=ttyS0,115200" GRUB_TERMINAL="console serial" GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"
2 grub-mkconfig
Update /boot/grub/grub.cfg with grub-mkconfig.
$ sudo grub-mkconfig -o /boot/grub/grub.cfg Generating grub configuration file ... Found linux image: /boot/vmlinuz-3.16.0-4-amd64 Found initrd image: /boot/initrd.img-3.16.0-4-amd64 done
Reboot Debian 9.
$ sudo reboot
3 Execution result
GRUB to monitor display is as below.
GRUB to serial console is as below. This article used "sudo virsh console <vmname>" for connecting serial console.
Login prompt to monitor display is as below. tty1 is displayed with press Ctrl + Alt + F1.
Login prompt to serial console is as below.
