diskimage-builder/doc/source/developer/invocation.rst

Developer Installation

Note that for non-development use you can use distribution packages or install the latest release via pip (usually in a separate virtualenv environment).

For development purposes, you can use pip -e to install the latest git tree checkout into a local development/testing virtualenv.

However, the recommended way is to use provided tox environments; e.g.

$ git clone https://opendev.org/openstack/diskimage-builder
$ cd diskimage-builder

$ tox -e bindep
$ sudo apt-get install <any-missing-packages-from-bindep>

$ tox -e venv -- disk-image-create ...

This will ensure you run with the right requirements.

Invocation

The image-create scripts should be run from the $PATH; this should will be automatically set if using a virtualenv or tox.

A range of options can be set on the command-line. Try -h for help.

Other options can be set by exporting variables; some variables for export are listed in lib/img-defaults. See specific element instructions for other variables that may be obeyed.

The image building scripts expect to be able to invoke commands with sudo. Thus if you want them to run non-interactively, you should either run them as root, with sudo -E, or allow your build user to run any sudo command without password.

Element priority

The variable ELEMENTS_PATH is a colon (:) separated path list to search for elements. The included elements tree is used when no path is supplied and is always added to the end of the path if a path is supplied. Earlier elements will override later elements, i.e. with ELEMENTS_PATH=foo:bar the element my-element will be chosen from foo/my-element over bar/my-element, or any in-built element of the same name.

Output

By default, the image building scripts will not overwrite existing disk images, allowing you to compare the newly built image with the existing one. To change that behaviour, set the variable OVERWRITE_OLD_IMAGE to any value that isn't 0. If this value is zero then any existing image will be moved before the new image is written to the destination.

Size reports

Setting the variable DIB_SHOW_IMAGE_USAGE will print out a summarised disk-usage report for the final image of files and directories over 10MiB in size. Setting DIB_SHOW_IMAGE_USAGE_FULL will show all files and directories. These settings can be useful additions to the logs in automated build situations where debugging image-growth may be important.