Serial Terminal Configuration in RHEL 7
Add, or update if already present, the following lines to /etc/default/grub:
GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200n8" GRUB_TERMINAL=serial GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"
GRUB_CMDLINE_LINUX_DEFAULT applies this configuration only to the default menu entry, use GRUB_CMDLINE_LINUX to apply it to all the menu entries.
NOTE: each line type above should only appear once within the /etc/default/grub file. If the line already exists, then just modify it rather than add a second copy of same. That is, only one GRUB_CMDLINE_LINUX_DEFAULT line should exist in the file, etc.
Rebuild the /boot/grub2/grub.cfg file by running the grub2-mkconfig -o command as follows:
On BIOS-based machines: ~]# grub2-mkconfig -o /boot/grub2/grub.cfg On UEFI-based machines: ~]# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg
Red Hat Enterprise Linux 8
