See full boot-up output on Glish

The default Linode images (when using GRUB2) don't output anything to the Glish console until the Linode has booted and is sat at the login prompt - all the output happens on the text console (Lish.)

Glish sits on the SeaBIOS boot screen until the login prompt.

Whilst this isn't a problem, it can be unnerving if you're not aware of this when rebooting your Linode.

I have updated my Linodes' /etc/default/grub file as follows, followed by grub2-mkconfig -o /boot/grub/grub.cfg (this is Fedora.)

Here's the default config (this is Fedora's, but Ubuntu is similar):

GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="console=ttyS0,19200n8 net.ifnames=0 rhgb "
GRUB_TERMINAL=serial
GRUB_SERIAL_COMMAND="serial --speed=19200 --unit=0 --word=8 --parity=no --stop=1"
GRUB_GFXPAYLOAD_LINUX=text

This configures only the serial TTY during boot-up.

I've updated my config to:

GRUB_TERMINAL_OUTPUT="console serial"
GRUB_CMDLINE_LINUX="console=tty0 console=ttyS0,19200n8 net.ifnames=0 rhgb "
GRUB_TERMINAL="console serial"
GRUB_SERIAL_COMMAND="serial --speed=19200 --unit=0 --word=8 --parity=no --stop=1"
# Removed GRUB_GFXPAYLOAD_LINUX=text

This now captures the GRUB menu and boot output onto Glish as well during the boot-up routine.

This isn't an issue with Linode's kernels - only when using GRUB2.

As it appears Linode's images are specifically configured this way, I'm curious if there's a reason why or is it a legacy thing from days before Glish existed and the only console needed was the serial one?

EDIT:

The source of my change was this post on ServerFault and the GRUB manual.