Linux From Scratch in QEMU

This project provides steps and scripts to build your own linux system in virtual machine envionment. The instruction we follow is Linux From Scratch verion 11.3 (https://www.linuxfromscratch.org/index.html)

Prerequisites

Host OS: RockyLinux 8 or other Linux distributions
Virtual Machine Environment: QEMU

Virtual Machine Setup

• Virtaul Disk 1: Install Virtual Machine Host OS
• Virtual Disk 2: Install Linux From Scratch(LFS)

Install Virtual Machine Host OS

1. Install RockyLiunx 8 OS in Virtual Disk 1(sda) by default Linux partition settings
2. prepare LFS partition

lsblk
## sdb      8:16    0    70G   0 disk

fdisk /dev/sdb
## create three partitions sdb1(512M), sdb2(1G), sdb3(68.5G) by command (ref: https://linux.die.net/man/8/gdisk). Note that sdb2 needs to change type "Linux swap / Solaris"(hex code=82)
## sdb1: /boot partition
## sdb2: swap
## sdb3: / partition

lsblk
## sdb1      8:16    0    512M    0 part
## sdb2      8:16    0    1G      0 part
## sdb3      8:16    0    68.5G   0 part

3. format partitions

mkfs -v -t ext4 /dev/sdb1
mkswap /dev/sdb2
mkfs -v -t ext4 /dev/sdb3

Install Linux From Scratch(LFS)

./run.sh

cd pkg_compile_cross_toolchain_script && ./install_all.sh

cd pkg_cross_compiling_temporary_tools_script && ./lfs_user_install_all.sh

cd pkg_chroot_tools && cat README ## following README

Setup QEMU Boot Order

TO-DO List

• Install sshd

cd /opt
./chroot_install_openssh.sh
vi /etc/ssh/sshd_config
## Set root login config
## === modify this line ===
PermitRootLogin yes

• Install wget

• Install netstat

• Install Gnome

Troubleshooting

pinging google.com hangs

1. Observe infrastructure from QEMU Environment
2. Modify ifconfig.eth0
3. Infra after modification
4. ping google.com again

Grub failed, cannot find vmlinuz-6.1.11-lfs-11.3

1. press c
   
2. type cd (hd and press tab, and you will see disks and partitions recognized by grub
3. setup root path in /boot/grub/grub.cfg file, in this case, root path is (hd0, msdos1)

set root=(hd0, msdos1)

VFS: Unable to mount root fs

1. Disk2 partitions were SOMETIMES recognized as /dev/sdc1, /dev/sdc2, and /dev/sdc3, but we expect /dev/sdb1~3, so if we configure grub.cfg like /dev/sdbX, it will casue this error.
2. It is highly recommanded to specify partitions by PARTUUID, command below shows partition PARTUUID information.

blkid
# /dev/sdb3: UUID="17b539e0-9a73-482c-ba8b-70e3353ba187" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="b4d939e3-03"

3. specify root=PARTUUID=XXXX

vi /boot/grub/grub.cfg
# set default=0
# set timeout=5
#
# insmod ext2
# set root=(hd0,msdos1)
#
# menuentry "GNU/Linux, Linux 6.1.11-lfs-11.3" {
#         linux   /vmlinuz-6.1.11-lfs-11.3 root=PARTUUID=b4d939e3-03 ro
# }

4. LFS boots successfully