Option 1 – Using bootloader
Use this guide: http://www.howtogeek.com/196520/grub2-101-how-to-access-and-use-your-linux-distributions-boot-loader/ . In my case this did not work.
Option 2 – Using SystemRescueCD
It might be that your VPS has a Linux Recovery Mode (not rescue mode) using a SystemRescueCD. If so, use this guide:
In my case the /dev/vda5 was not mountable, because it was password encrypted. That was why I had to use these commands:
In summary it went like:
$ fdisk -l $ mkdir /mnt/system $ mount /dev/vda5 /mnt/system # /dev/vda5 is the main Linux partition mount: unknown filesystem type 'crypto_LUKS' # I received an error that this partition is encrpted, so the I used: $ cryptsetup open /dev/vda5 newRoot $ modprobe dm-mod $ vgchange -ay $ lvscan # hopefully the root is displayed now. Mount this one mount /dev/xx/yy /mnt/system # ACCESS :D :D chroot /mnt/system passwd # Enter your new root password
Then I was able to reset my password, by entering passwd.