How do I invoke the kernel with serial console on 12.04?
In 10.04 I could just add
console=ttyS0 in kernel line or
install quiet console=ttyS0 on boot: line
How do I do that in 12.04?
There is nothing special in 12.04. Just follow the information from: https://help.ubuntu.com/community/SerialConsoleHowto
1) Paste the following into /etc/init/ttyS0.conf
# ttyS0 - getty # # This service maintains a getty on ttyS0 from the point the system is # started until it is shut down again. start on stopped rc or RUNLEVEL= stop on runlevel [!2345] respawn exec /sbin/getty -L 9600 ttyS0 vt102
2) Ask upstart to start the getty
sudo start ttyS0
This will get you access to console. To get access to Linux init console, configure grub.
1) Edit /etc/default/grub to contain the following lines
GRUB_CMDLINE_LINUX="console=tty1 console=ttyS0,9600n8" GRUB_TERMINAL=serial GRUB_SERIAL_COMMAND="serial --speed=9600 --unit=0 --word=8 --parity=no --stop=1"
2) update grub
I am using 9600 just because I am using a server where the BIOS is already redirected over seria using 9600. If you don't care about the BIOS settings, feel free to use a faster serial line.