Issue booting in single user mode

bcoats

I've tried two methods to get into single user mode: rd.break and rw init=/sysroot/bin/sh. Both leave me with a flashing cursor only after pressing ctrl-x. I'm new to linux so I'm sure I missed something.

Lab 4.1
CentOS 8

lee42x

Hi, I verified the documentation and all seems to work, however, lets see if we can sort the issue.

• when changing the "init" program try adding only ** init=/bin/bash** to the command line.
• when adding rd.break to the kernel line there is not a lot of commands but echo,cat and sed should be available along with journalctl .
• Please select a "distribution" kernel not a locally compiled one, here is an example that I used:
  CentOS Linux (4.18.0-147.5.1.el8_1.x86_64) 8 (Core)

Regards Lee

ankush3597

I personally find lab instructions of not much use as those are high level only. For this If you are running CentOs 8 then just add rd.break at the end of the statement which is starting from linux keyword and hit Ctrl+X this should work.

k0dard

I've stumbled upon this question some time ago and noticed that I cannot boot my VMs used for this course into single user mode either. Whatever parameter I add I finish with a blinking cursor. After some trial and error, I discovered the problem was in another kernel boot parameter I've added (console=ttyS0) in order to be able to access my VMs through CLI (virsh)
Hope this will be helpful for someone maybe

coop

Unfortunately, it seems that the methods to get into single user mode (or to get to a VT as well) depend a lot of the choice of hypervisor (KVM, VirtualBox, VMware etc) and the choice of distribution and its version and the kernel options as well. It used to be there was a simple prescription that always worked, but now it is often a voyage of discovery to sort this out. Glad you found the solution for you. Since ttys0 sounds like a serial port, I find it surprising, but so it goes!

k0dard

Yes, indeed, but every challenge is a chance to learn something new
I think now that my first post was a bit confusing - what I wanted to say is that at some point I've added the parameter console=ttyS0which is a serial port, and I did it to be able to access my VM through CLI. Without it virsh is giving the blank screen with blinking cursor, but with it single boot mode from virt-manager isn't possible (for me at least) since I guess the output gets redirected to serial port... So, in the end in order to boot to single user mode from virt-manager console parameter has to be removed.
If my presumptions are incorrect and anyone has an explanation I'd be grateful to here it