Challenges of Lab 3.1

gserlenga

I just completed Lab 3.1: Booting into Non-Graphical Mode Using GRUB.

I just wanted to say a few things things about it here, to whoever might be reading.

The system I am working on is an x86-64 architecture running Debian/sid with the `lightdm` display manager and `Xfce4` as the desktop environment. The system's root partition is `dm-crypt` encrypted and resides inside an `LVM` logical volume.

This installation already has pre-made `emergency console` GRUB menu entries to boot into an emergency shell, but I wanted to do the lab correctly by manually editing the kernel command line for the default GRUB boot menu stanza. I tried appending `text`, this just took me straight into the graphical lightdm login screen. I tried `single`, this booted into the same `emergency mode` as the pre-defined GRUB menu entries already do. However my system has no root password set, so I am unable to as login as root user except by using: $ sudo su -

I then appended `3`, for run level 3, to the kernel command line. Some research revealed that run levels 2-5 are the same on newer Debian systems, i.e. "multiple user, with NFS and network, only text login". Runlevels 2-5 on Debian are intended to be defined as desired by the sysadmin. I was able to login to my user account and get to a console/text-mode environment which was fully operational in this way.

In attempting to bring the system back up to graphical mode, the command: $ sudo startx dropped me into the Xfce4 desktop environment as root user.

I do not have an ~/.xinitrc or ~/.xserverrc file defined in my home directory to be used by the `xinit` X11 server initialization process which the `startx` command reads for instructions. Because of this, `$ sudo startx` does not load my user account with all associated settings and customizations in an Xfce4 graphical session. In the end, I used the command: $ sudo systemctl start lightdm.servicemy Debian is using `systemd` as init. This started up the graphical login session on tty7 with a `lightdm` login prompt and splash screen as usual. To close out a graphical login on tty7, either of the commands: $ sudo /etc/init.d/lightdm stop or $ sudo systemctl stop lightdm.service worked. I know this is ahead of the subject area of this question but I wanted to write it down for anyone else's use.

I wrote this just to inform the class admin or anyone else of the challenges I encountered in this lab ... Thanks for taking the time to read ...

[email protected]

This lab will not work for me on CentOs 7. I've tryed all the listed commands.

gserlenga

I think you're not alone on this, as this lab required alot of outside research for me as well. If you have a specific question, I might be able to help.

coop

THanks geerlenga for you detailed response.

The instructions do not list the systemctl equivalents which would have been better, like
instead of

service gdm restart

systemctl restart gdm

etc. (or lightdm for debian, or I have a RHEL7 system running xfce that needs this too.)

But please note, this is one of those things that every $#%! distribution handles somewhat differently, and we cannot give a long table of things -- it also changes from version to version, ie., ubuntu 14.04 is different that 15.04, debian jessie (8) than earlier etc.
So what you guys are doing, experimenting and figuring it out, is the way to do it unfortunately.

Please make sure you do *not* edit the lines in grub.cfg directly, only do it in the interactive menu, so you can still boot normally!

As far as not wokring on CentOS7 I don't know. The lab was written and tested on RHEL7 so it should be the same.

gserlenga

Thanks Jerry, I don't mind at all having to do a large amount of outside research in working on certain chapters in this course, its what I would expect to have to do in a real world job situation where new and unexpected situations pop up on a daily and hourly basis. Experimentation, breaking things myself, and then being forced to learn to fix them myself, is pretty much the primary method I have ever used in learning any new skill, this is no different.

I have worked a bit with almost all the major Linux distro families (Arch, CentOS/Fedora, Ubuntu/Mint, and Debian). Almost every one does certain things differently and I settled on Debian as my preferred distro just because I like the management tools built into Debian and appreciate the lack of corporate affiliations and the social contract. Been looking into exploring the BSD's as well to widen my skills though I know that is outside of the scope of this course.

Anyway thanks for reading my long-winded posts and I for one appreciate your input and work on developing the course.