how to customize ubuntu iso image

To customize an Ubuntu ISO image, you can use tools like Cubic or follow a more manual process involving mounting the ISO, modifying files within a chroot environment, and then rebuilding the ISO. Cubic provides a GUI wizard for easier customization, while the manual approach offers more control. 

Using Cubic (GUI Wizard):

1. Install Cubic: You can install Cubic using a PPA (Personal Package Archive) on your Ubuntu system: 

Code

    sudo apt-add-repository ppa:cubic-wizard/release
    sudo apt update
    sudo apt install cubic

1. Open Cubic: Launch Cubic from the application menu.
2. Create a Custom ISO: Cubic will guide you through the process, allowing you to select the base ISO, customize packages, add/remove software, and more. 
3. Build the ISO: Cubic will automatically generate a custom ISO file based on your selections. 

Manual Customization (Chroot Environment):

1. Mount the ISO: Mount the Ubuntu ISO image to a directory, for example:

Code

    sudo mkdir /mnt/iso
    sudo mount -o loop /path/to/ubuntu.iso /mnt/iso

1. Chroot: Create a chroot environment within the mounted ISO: 

Code

    sudo mount -o bind /dev /mnt/iso/dev
    sudo mount -o bind /dev/shm /mnt/iso/dev/shm
    sudo chroot /mnt/iso

1. Make Changes: Inside the chroot, you can make various modifications:
   • Install Packages: Use apt-get install to install additional software.
   • Configure Services: Modify configuration files in /etc to adjust services.
   • Add/Remove Users: Use adduser or userdel to manage user accounts.
   • Customize GRUB: Edit /etc/grub.d/ scripts to customize the boot menu.
2. Rebuild the ISO: After making your changes, you’ll need to rebuild the ISO using tools like Genisoimage or mkisofs. 
3. Unmount: Once you’ve rebuilt the ISO, unmount the ISO and chroot environment:

Code

    sudo umount /mnt/iso/dev
    sudo umount /mnt/iso/dev/shm
    exit # Exit the chroot environment
    sudo umount /mnt/iso

Additional Tips:

• Preseeding:For automated installations, you can create a preseed file (e.g., ubuntu-custom.seed) to answer installation prompts automatically, according to an Ask Ubuntu post. 
• Custom Folders:You can add custom folders to the ISO and copy them to the Ubuntu OS during installation. 
• Testing:It’s always a good idea to test your customized ISO before using it on real hardware or devices.