jarmitage/bela-image-builder_notes.md

## bela-image-builder_notes.md

      
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              bela-image-builder_notes.md
            
          
    Building a Bela image using VirtualBox and Ubuntu


Size of VM after running ./build_bela.sh: 27.52GB
Size of bela-image-builder folder after running ./build_bela.sh: 12GB

Creating the Ubuntu VM


Install VirtualBox
Download an Ubuntu image
Set up an Ubuntu VM in VirtualBox (you will need ≥30GB disk and ≥2GB RAM)
Boot the VM and install the image
Let Ubuntu run some updates, then run sudo apt-get update && sudo apt-get upgrade
For convenience, add some apps to favourites (dock): Settings, TextEditor, Terminal

Install and configure git and ssh


Install git and setup global config

sudo apt-get install git git-core
git config --global user.email johndoe@example.com
git config --global user.name "John Doe"

If you want to git clone the image builder repo rather than just download it, set up ssh https://help.github.com/articles/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent/
Optional: install zsh and Sublime Text

(Optionally) set up a decent shell (setting up zsh on Ubuntu: https://gist.github.com/tsabat/1498393)
sudo apt-get install curl zsh
sh -c "$(curl -fsSL https://raw.github.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"
chsh -s `which zsh`
sudo shutdown -r 0

Ubuntu does not come with a text editor, so you may also want to install something like Sublime Text:
https://www.sublimetext.com/docs/3/linux_repositories.html
wget -qO - https://download.sublimetext.com/sublimehq-pub.gpg | sudo apt-key add -
sudo apt-get install apt-transport-https
echo "deb https://download.sublimetext.com/ apt/stable/" | sudo tee /etc/apt/sources.list.d/sublime-text.list
sudo apt-get update
sudo apt-get install sublime-text

Install bela-image-builder dependencies

Install some necessary dependencies:

The build script will complain about the absence of qemu-arm-static when it means qemu-user-static
libtool-bin is required because libtool doesn't install binaries for some reason

sudo apt-get install qemu qemu-user-static dh-autoreconf daemontools binutils-arm-linux-gnueabihf lzma lzop libtool-bin debootstrap kpartx bison flex pkg-config libncurses5-dev:amd64

If you can't find all the above packages, find alternatives:
sudo apt-get install apt-file
sudo apt-file update
sudo apt-file search PACKAGE_NAME

For example in this case I used the following alternatives compared to what the build script asked for:
autoreconf -> dh-autoreconf
setuidgid  -> daemontools
arm-linux-gnueabihf-ranlib -> binutils-arm-linux-gnueabihf

Clone/download the repo and run the main script

Clone the repo somewhere (e.g. ~/Documents/git/)
git clone git@github.com:BelaPlatform/bela-image-builder.git

Now try running the script as root
cd path/to/bela-image-builder
sudo ./build_bela.sh

The result

Eventually you will get a ~3.9GB file bela.img. At this point you should take a Snapshot of your VM.
To transfer this file to your host machine, you may want to first compress it (use -k to prevent deleting the original file, and --verbose for progress updates):
xz -k --verbose bela.img

Or you may not, since this could take longer than just copying it to your host and compressing it there if required.
In the case that your host is a Mac, you will need to set up Guest Additions which is somewhat involved:
https://matthewpalmer.net/blog/2017/12/10/install-virtualbox-mac-high-sierra/index.html
Note on above: I couldn't access the folder from my user so had to use sudo cp to copy to the shared folder.
To use the image file, follow this article:
https://github.com/BelaPlatform/Bela/wiki/Manage-your-SD-card#flashing-an-sd-card
Build process notes (@giuliomoro)

The build process is slow. There are three steps in the build process that take the longest (after the first run, which is the one that does all the downloads, including the KERNEL):

Building the kernel
Building the base debian image (the debootstrap command, which reads packages.txt)
The scripts/chroot.sh part. This runs inside a chroot, using qemu, so everything that happens in here is using qemu to emulate the ARM architecture.

The first two steps can normally be skipped when you re-build an image, as the kernel version is frozen anyhow, and debootstrap takes forever (and requires a lot of network bandwidth).
Most of the changes these days happen either in:

packages.txt in which case you need to re-run debootstrap, so you can run, e.g.:  sudo ./build_bela.sh --no-kernel --no-bootloader --no-build-xenomai --no-downloads
Or in chroot.sh or in misc/rootfs/ (files that are manually created on the file system, so you can run, e.g. sudo ./build_bela.sh --no-kernel --cached-fs --no-bootloader --no-build-xenomai --no-downloads

It could be tempting for you to add your packages to packages.txt, but I'd suggest maybe you add them as an apt-get install ... line at the bottom of scripts/chroot.sh, so you can more quickly iterate the builds and test