|Candidates should be able to select, install and configure a boot manager
Key Knowledge Areas:
- Providing alternative boot locations and backup boot options.
- Install and configure a boot loader such as GRUB Legacy.
- Perform basic configuration changes for GRUB 2.
- Interact with the boot loader
Terms and Utilities
In part 1 we looked at installing and managing GRUB now we look at GRUB2
GRUB has served as long and well for many years. GRUB2 has been around for a little while in openSUSE and Ubuntu but we now see it in Enterprise Linux with its first showing with Red Hate Enterprise Linux 7 and the default boot loader. In many respects GRUB2 is similar but the configuration file is very much more complex and generated with grub2-mkconfig (/sbin/grub2-mkconfig). The configuration file now has or more standard name, /boot/grub2/grub.cfg but it is not edited directly. The configuration comes from the /etc/default/grub file and the directory /etc/grub.d/ . It is here we would add our own entries, but new kernels and ram disks are detected and added to the menu automatically.
To set the menu timeout we can edit the /etc/default/grub file and change the value to whatever we need..
If we need to change the default menu item, this can be achieved via the following command.
This would set the second item in the menu to be the default, counting from 0. After any change we need to regenerate the grub.cfg
grub2-mkconfig -o /boot/grub2/grub.cfg