Sometime we wil forget the root password. root password can be reset from the grunt mode.
Restart the Oracle Linux 7 server. Immediately press any key open the kernal list.
Use the cursor keys to highlight the default boot loader entry. On the GRUB 2 boot screen, press e to edit the current entry.
Using the cursor keys(scroll down using navigation key), navigate to the line that starts with linux16 if you are using on x86-64 BIOS-based systems and navigate to the line that starts with linux line on 64-Bit IBM Power Series.
Append rd.break or rd.break enforcing=0 to the end of the line. Both gives the same result.
Press Ctrl+x to boot using the modified config.
Type the below command in terminal. Server will take time to restart. Use your new password.