Remember to encrypt your storage drives to protect the sensitive information from people that could steal your hardware and reset the password. Also, do not use automatic cloud services without the possibility of Installation from your own CD/DVD ISOs if they don't allow you to encrypt the virtual system and storage drives.

Methods:
- Reset root password editing Grub2 menu options
- Reset root password using Grub2 or Installation CD menu Advanced Options
- Reset root password using LiveCD or Pendrive with bootable Linux


- Reset root password editing Grub2 menu options:
(Pending)
References:
Web: http://www.debianadmin.com/how-to-reset-debian-root-password.html
File: How to Reset debian Root Password _ Debian Admin.pdf

- Reset root password using Grub2 or Installation CD menu Advanced Options:
(Pending)

- Reset root password using LiveCD or Pendrive with bootable Linux:
(Pending)


References:
Topic: Recovering a Lost Linux Password: 3 Methods
Video: https://www.youtube.com/watch?v=CLwqGce6AGo
Topic: Repair Grub
Guide: Boot Loaders and Dual Boot, section "- Repair Grub".
Topic: System rescue
Guide: System Rescue