| Weight | 2 |
| Description | 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
- /boot/grub/menu.lst
- grub-install
- MBR
- superblock
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..
GRUB_TIMEOUT=5
If we need to change the default menu item, this can be achieved via the following command.
grub2-set-default 1
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