My journey through Linux From Scratch (LFS)

This doesn't intend to be a guide on the LFS book, but much more a place to take notes of the steps taken that aren't provided in the book itself.

My physical machine runs Ubuntu 16.04, and I didn't want to install all the LFS base system in this host.

As I also wanted to become more confortable in the use of Vagrant, and maybe event automate the first steps of LFS through it, I've decided to use Vagrant to create a dedicated VM for LFS.

I chosed Debian as the base host for LFS because is the distro that I'm more confortable, and I didn't want to learn how to use another package management system during the LFS journey.

Choosing a boot/services manager

There are two stable editions of the LFS: the classical one uses SysVinit to manage the booting, and there is an alternative with systemd.

Even though I agree with the criticism that systemd is too complex and out of the unix philosofy, it is the defacto services manager in both RHEL and Debian (and respective derivatives). Because of this I will follow the systemd edition to be able to know more about the usage of it.

If this were a LFS build more focused in continuous usage (instead of learning) I probably would stick with SysVinit, or maybe experiment with OpenRC.

Creating and running a dedicated VM for LFS using Vagrant

A basic Debian VM will be the starting point where the system requirements for LFS will be installed. Vagrant (and VirtualBox) must be already installed.

# Creating a dedicated directory for the LFS vm
mkdir lfs_vm
cd lfs_vm

# this puts a Vagrantfile in the lfs_vm folder, pointing to a debian-stretch "box"
vagrant init debian/contrib-stretch64

# the Debian image will be automatically downloaded at the first run of this command, and kept in the boxes cache
vagrant up 

# connects to the VM through SSH
vagrant ssh 

The Vagrantfile created by the command vagrant init debian/contrib-stretch64 is available at this repository, but currently it's just the default content.

After being connected to the VM I updated the system using APT

apt update
apt upgrade --yes

Installing the host requirements at the VM

The first practical step from the LFS book is the installation of the software requirements in the base system (the Debian VM).

Instead of manually checking the requirements, I ran the version-check.sh script and checked the messages that it spit out.

$ ./version-check.sh 
bash, version 4.4.12(1)-release
/bin/sh -> /bin/dash
ERROR: /bin/sh does not point to bash

There is an explanation of why Debian (and Ubuntu) are pointing /bin/sh to /bin/dash. As we are in a dedicated VM for LFS, let's simply change the link back to bash:

sudo rm /bin/sh
sudo ln -s /bin/bash /bin/sh

Running version-check.sh again pointed at some missing software. This was fixed with the following packages:

sudo apt install bison gawk g++ texinfo

Bison, gawk and g++ could be identified directly. texinfo provides the makeinfo requirement.

Most software at the host is not exactly in the same version, but all the hard requirements (not using newer than XX) are being met.