Emergency
Grub
- Reach the grub and chose the first line
- Use 'e' to edit
- Go to the "vmlinux" line to add 'rd.break' at the end (This change is temporary)
- Press 'CTRL+x' to exit an run it
Rescue
Send a Ctrl+Alt+Del to your system using the relevant button or menu entry.
When the boot-loader menu appears, press any key to interrupt the countdown, except Enter.
Use the cursor keys to highlight the default boot loader entry.
Press e to edit the current entry.
Use the cursor keys to navigate to the line that starts with linux.
Press End to move the cursor to the end of the line.
Append rd.break to the end of the line.
Press Ctrl+x to boot using the modified configuration.
At the switch_root prompt, remount the /sysroot file system read/write, then use chroot to go into a chroot jail at /sysroot.
switch_root:/# mount -o remount,rw /sysroot
switch_root:/# chroot /sysroot
Set the root password to redhat.
sh-4.4# passwd root
Changing password for user root.
New password: redhat
BAD PASSWORD: The password is shorter than 8 characters
Retype new password: redhat
passwd: all authentication tokens updated successfully.
Configure the system to automatically perform a full SELinux relabel after boot.
sh-4.4# touch /.autorelabel
Type exit twice to continue booting your system. The system fails to boot because of an issue you resolve in the next step.
Selinux
⚠ Make sure SELinux allows the file changed
touch .autorelabel
This will signal SELinux on the next reboot that the filesystem has changed (the changed password) and allow the change to be loaded.
Type 'exit' then 'reboot'