# Create live custom Ubuntu from scratch

## Prerequisites (GNU/Linux Debian/Ubuntu)

Install applications we need to build the environment.

```
sudo apt-get install \
    debootstrap \
    squashfs-tools \
    xorriso \
    grub-pc-bin \
    grub-efi-amd64-bin \
    mtools
```

```
mkdir $HOME/live-ubuntu-from-scratch
```

## Bootstrap and Configure Ubuntu
```
sudo debootstrap \
    --arch=amd64 \
    --variant=minbase \
    bionic \
    $HOME/live-ubuntu-from-scratch/chroot \
    http://us.archive.ubuntu.com/ubuntu/
```

```
sudo mount --bind /dev $HOME/live-ubuntu-from-scratch/chroot/dev

sudo mount --bind /run $HOME/live-ubuntu-from-scratch/chroot/run
```

## Access chroot environment
```
sudo chroot $HOME/live-ubuntu-from-scratch/chroot
```

1. **Configure mount points**
   ```
   mount none -t proc /proc

   mount none -t sysfs /sys

   mount none -t devpts /dev/pts

   export HOME=/root

   export LC_ALL=C
   ```

2. **Set a custom hostname**
   ```
   echo "ubuntu-live" > /etc/hostname
   ```

3. **Configure apt sources.list**
   ```
   cat <<EOF > /etc/apt/sources.list
   deb http://us.archive.ubuntu.com/ubuntu/ bionic main restricted universe multiverse 
   deb-src http://us.archive.ubuntu.com/ubuntu/ bionic main restricted universe multiverse 

   deb http://us.archive.ubuntu.com/ubuntu/ bionic-security main restricted universe multiverse 
   deb-src http://us.archive.ubuntu.com/ubuntu/ bionic-security main restricted universe multiverse 

   deb http://us.archive.ubuntu.com/ubuntu/ bionic-updates main restricted universe multiverse 
   deb-src http://us.archive.ubuntu.com/ubuntu/ bionic-updates main restricted universe multiverse    
   EOF
   ```

4. **Update indexes packages**
   ```
   apt-get update
   ```

5. **Install systemd**
   ```
   apt-get install -y systemd-sysv
   ```

5. **Configure machine-id and divert**
   ```
   dbus-uuidgen > /var/lib/dbus/machine-id

   dpkg-divert --local --rename --add /sbin/initctl
   
   ln -s /bin/true /sbin/initctl

   ln -fs /var/lib/dbus/machine-id /etc/machine-id
   ```

6. **Install packages needed for Live System**
   ```
   apt-get install -y \
       ubuntu-standard \
       casper \
       lupin-casper \
       discover \
       laptop-detect \
       os-prober \
       network-manager \
       resolvconf \
       net-tools \
       wireless-tools \
       wpagui \
       locales \
       linux-generic
   ```
  
7. **Graphical installer**
   ```
   apt-get install -y \
       ubiquity \
       ubiquity-casper \
       ubiquity-frontend-gtk \
       ubiquity-slideshow-ubuntu \
       ubiquity-ubuntu-artwork
   ```

8. **Install window manager**
   ```
   apt-get install -y \
       plymouth-theme-ubuntu-logo \
       ubuntu-gnome-desktop \
       ubuntu-gnome-wallpapers
   ```

9. **Install usefull applications**
   ```
   apt-get install -y \
       clamav-daemon \
       terminator \
       apt-transport-https \
       curl \
       vim \
       nano
   ```

10. **Install Visual Studio Code**

    1. Download and install the key 
       ```
       curl https://packages.microsoft.com/keys/microsoft.asc | gpg --dearmor > microsoft.gpg

       install -o root -g root -m 644 microsoft.gpg /etc/apt/trusted.gpg.d/
       
       echo "deb [arch=amd64] https://packages.microsoft.com/repos/vscode stable main" > /etc/apt/sources.list.d/vscode.list

       rm microsoft.gpg
       ```

    2. Then update the package cache and install the package using:
       ```
       apt-get update
       
       apt-get install -y code
       ```

11. **Install Google Chrome**

    1. Download and install the key 
       ```
       wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -
       ```

    2. Add the key to the repository
       ```
       echo "deb http://dl.google.com/linux/chrome/deb/ stable main" > /etc/apt/sources.list.d/google-chrome.list
       ```

    3. Finally, Update repository and install Google Chrome.
       ```
       apt-get update

       apt-get install google-chrome-stable
       ```

12. **Install Java JDK 8**
    ```
    apt-get install -y \
        openjdk-8-jdk \
        openjdk-8-jre
    ```

13. **Remove unused applications**
    ```
    apt-get purge -y \
        transmission-gtk \
        transmission-common \
        gnome-mahjongg \
        gnome-mines \
        gnome-sudoku \
        aisleriot \
        hitori
    ```

14. **Remove unused packages**
    ```
    apt-get autoremove -y
    ```

15. **Reconfigure packages**

    1. **Generate locales**
       ```
       dpkg-reconfigure locales
       ```

    2. **Reconfigure resolvconf**
       ```
       dpkg-reconfigure resolvconf
       ```

    3. **Configure network-manager**
       ```
       cat <<EOF > /etc/NetworkManager/NetworkManager.conf
       [main]
       rc-manager=resolvconf
       plugins=ifupdown,keyfile
       dns=dnsmasq
       
       [ifupdown]
       managed=false
       EOF
       ```

    4. **Reconfigure network-manager**
       ```
       dpkg-reconfigure network-manager
       ```

15. **Cleanup the chroot environment**

    1. If you installed software, be sure to run
       ```
       rm /var/lib/dbus/machine-id
       ```

    2. Remove the diversion
       ```
       rm /sbin/initctl

       dpkg-divert --rename --remove /sbin/initctl
       ```

    3. Clean up
       ```
       apt-get clean

       rm -rf /tmp/* ~/.bash_history

       umount /proc
       
       umount /sys
       
       umount /dev/pts

       export HISTSIZE=0
       
       exit
       ```

## Unbind mount points
```
sudo umount $HOME/live-ubuntu-from-scratch/chroot/dev

sudo umount $HOME/live-ubuntu-from-scratch/chroot/run
```

## Create the CD image directory and populate it

1. Access build directory
   ```
   cd $HOME/live-ubuntu-from-scratch
   ```

2. Create directories
   ```
   mkdir -p image/{casper,isolinux,install}
   ```

2. Copy kernel images
   ```
   sudo cp chroot/boot/vmlinuz-**-**-generic image/casper/vmlinuz

   sudo cp chroot/boot/initrd.img-**-**-generic image/casper/initrd
   ```

3. Copy memtest binary
   ```
   sudo cp chroot/boot/memtest86+.bin image/install/memtest
   ```

## Grub configuration

   1. Access build directory
      ```
      cd $HOME/live-ubuntu-from-scratch
      ```
   
   2. Create image/isolinux/grub.cfg
      ```
      cat <<EOF > image/isolinux/grub.cfg

      search --set=root --file /ubuntu

      insmod all_video

      set default="0"
      set timeout=30

      menuentry "Try Ubuntu without installing" {
         linux /casper/vmlinuz boot=casper quiet splash ---
         initrd /casper/initrd
      }

      menuentry "Install Ubuntu" {
         linux /casper/vmlinuz boot=casper only-ubiquity quiet splash ---
         initrd /casper/initrd
      }

      menuentry "Check disc for defects" {
         linux /casper/vmlinuz boot=casper integrity-check quiet splash ---
         initrd /casper/initrd
      }

      menuentry "Test memory" {
         linux /install/memtest
      }
      EOF
      ```

## Create manifest

1. Access build directory
   ```
   cd $HOME/live-ubuntu-from-scratch
   ```

2. Generate manifest
   ```
   sudo chroot chroot dpkg-query -W --showformat='${Package} ${Version}\n' | sudo tee image/casper/filesystem.manifest

   sudo cp -v image/casper/filesystem.manifest image/casper/filesystem.manifest-desktop

   sudo sed -i '/ubiquity/d' image/casper/filesystem.manifest-desktop
   
   sudo sed -i '/casper/d' image/casper/filesystem.manifest-desktop
   
   sudo sed -i '/discover/d' image/casper/filesystem.manifest-desktop
   
   sudo sed -i '/laptop-detect/d' image/casper/filesystem.manifest-desktop
   
   sudo sed -i '/os-prober/d' image/casper/filesystem.manifest-desktop
   ```

## Compress the chroot

1. Access build directory
   ```
   cd $HOME/live-ubuntu-from-scratch
   ```

2. Create squashfs
   ```
   sudo mksquashfs chroot image/casper/filesystem.squashfs
   ```

3. Write the filesystem.size
   ```
   printf $(sudo du -sx --block-size=1 chroot | cut -f1) > image/casper/filesystem.size
   ```

## Create diskdefines

1. Access build directory
   ```
   cd $HOME/live-ubuntu-from-scratch
   ```

2. Create file image/README.diskdefines
   ```
   cat <<EOF > image/README.diskdefines
   #define DISKNAME  Ubuntu from scratch
   #define TYPE  binary
   #define TYPEbinary  1
   #define ARCH  amd64
   #define ARCHamd64  1
   #define DISKNUM  1
   #define DISKNUM1  1
   #define TOTALNUM  0
   #define TOTALNUM0  1
   EOF
   ```

## Recognition as an Ubuntu from scratch

1. Access build directory
   ```
   cd $HOME/live-ubuntu-from-scratch
   ```

2. Create an empty file named "ubuntu" and a hidden ".disk" folder. 
   ```
   touch image/ubuntu
   
   mkdir image/.disk
   ```

## Create ISO Image for a LiveCD (BIOS + UEFI)

1. Access image directory
   ```
   cd $HOME/live-ubuntu-from-scratch/image
   ```

2. Create a grub UEFI image
   ```
   grub-mkstandalone \
      --format=x86_64-efi \
      --output=isolinux/bootx64.efi \
      --locales="" \
      --fonts="" \
      "boot/grub/grub.cfg=isolinux/grub.cfg"   
   ```

4. Create a FAT16 UEFI boot disk image containing the EFI bootloader
   ```
   (
      cd isolinux && \
      dd if=/dev/zero of=efiboot.img bs=1M count=10 && \
      sudo mkfs.vfat efiboot.img && \
      mmd -i efiboot.img efi efi/boot && \
      mcopy -i efiboot.img ./bootx64.efi ::efi/boot/
   )
   ```

5. Create a grub BIOS image
   ```
   grub-mkstandalone \
      --format=i386-pc \
      --output=isolinux/core.img \
      --install-modules="linux normal iso9660 biosdisk memdisk search tar ls" \
      --modules="linux normal iso9660 biosdisk search" \
      --locales="" \
      --fonts="" \
      "boot/grub/grub.cfg=isolinux/grub.cfg"
   ```

6. Combine a bootable Grub cdboot.img
   ```
   cat /usr/lib/grub/i386-pc/cdboot.img isolinux/core.img > isolinux/bios.img
   ```

7. Generate sha256sum.txt
   ```
   sudo /bin/bash -c "(find . -type f -print0 | xargs -0 sha256sum | grep -v "\./sha256sum.txt" > sha256sum.txt)"
   ```

7. Create iso from the image directory using the command-line
   ```
   sudo xorriso \
      -as mkisofs \
      -iso-level 3 \
      -full-iso9660-filenames \
      -volid "Ubuntu from scratch" \
      -eltorito-boot \
         boot/grub/bios.img \
         -no-emul-boot \
         -boot-load-size 4 \
         -boot-info-table \
         --eltorito-catalog boot/grub/boot.cat \
      --grub2-boot-info \
      --grub2-mbr /usr/lib/grub/i386-pc/boot_hybrid.img \
      -eltorito-alt-boot \
         -e EFI/efiboot.img \
         -no-emul-boot \
      -append_partition 2 0xef isolinux/efiboot.img \
      -output "../ubuntu-from-scratch.iso" \
      -graft-points \
         "." \
         /boot/grub/bios.img=isolinux/bios.img \
         /EFI/efiboot.img=isolinux/efiboot.img
   ```