Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ====== Grub2 ====== **General Information** Grub2 is used by RHEL/CentOS 7. It is quite different from Grub1. **Checklist** * Distro(s): Any * Other: Grub2 ---- ====== Grub2 Files ====== Grub2 files: * /etc/default/grub => grub2 variables (can be edited, then menus re-generated) * **Typically, this is the only file you should be hand editing.** * grub2 generated menu (**do not edit directly; changes will be over-written**) * EL7: /boot/grub2/grub.cfg * Ubuntu: /boot/grub/grub.cfg * /etc/grub.d/ => individual files used internally by grub2 Grub2 symlinks * /etc/grub2.cfg => symlink to /boot/grub2/grub.cfg * /etc/sysconfig/grub => symlink to /etc/default/grub ---- ====== Grub2 Commands ====== **View the active kernel that is the default the system will boot to** <code bash> grub2-editenv list saved_entry=CentOS Linux (3.10.0-327.3.1.el7.x86_64) 7 (Core) </code> \\ **View list of available kernels displayed on grub menu** <code bash> grep ^menuentry /boot/grub2/grub.cfg menuentry 'CentOS Linux (3.10.0-327.3.1.el7.x86_64) 7 (Core)' ... menuentry 'CentOS Linux (3.10.0-327.el7.x86_64) 7 (Core)' ... menuentry 'CentOS Linux (0-rescue-15bdd5425c924660bb6c9979dc071d56) 7 (Core)' ... </code> \\ **Set default kernel for grub system boot (permanent)** <code bash> grub2-set-default 'CentOS Linux (3.10.0-327.3.1.el7.x86_64) 7 (Core)' </code> * Note: Copy/paste including the single quotes from the "grep ^menuentry" output \\ **Changing grub2 kernel arguments** - Edit grub2 variables<code bash>vim /etc/default/grub</code> - After making changes to grub2 variables, re-generate the grub2 menu<code bash>grub2-mkconfig -o /boot/grub2/grub.cfg</code> ---- linux_wiki/grub2.txt Last modified: 2019/07/21 15:50by billdozor