It may happen that you lose access to your Centos system, for example in the network configuration or the fstab, as a result of which you can no longer reach the system properly. In these cases where the start-up of the system is no longer correct, and where you no longer have access, this manual can offer a solution. This explanation is accompanied with a video instruction at the bottom of this document.
To still gain access to your system, follow the steps below.
- Click in the left side menu on the rolldown menu "Compute" and then "Instances"
- Select the "Console" option in the Centos instance to open a console screen
- Make sure you have a working console prompt and your keyboard responds
- Then click on the "Send CtrlAltDel" button at the top right
The system will now restart.
- As soon as you see the centos grub boot menu, press the letter "e" on your keyboard.
- You now enter an editor screen where you can change the grub boot parameters
- At the bottom of the file in which you edited you have to adjust a number of settings
Look for the line below that looks similar to this one.
linux16 /boot/vmlinux-3.xxxxxx root = UUID = d4c71eab5c-4320-acf2-a900d38a60ee ro rhgb quiet console = tty0 consoleblank = 0 elevator = n on timeout = 10 crashkernel = auto console = ttyS0,115200 LANG = en_US.UTF- 8 initrd16 /boot/initramfs-3.10.0-862.xxxxximgh
- Remove the option: "console = ttyS0,115200"
- And replace it with the following option: "rd.break enforcing = 0"
- Keyboard on your keyboard "CTRL + X"
- After this the system will restart
As soon as the system is back, you will see a user prompt. To gain access to the root file system you need to take a few more steps.
- Remount the file-system read / write: "mount -o remount, rw / sysroot"
- Chroot the root file-system: "mount -o remount, rw / sysroot"
From this point you can, for example, reset the root password, or adjust the network configuration or correct another setting.