improved the introduction

This commit is contained in:
Bruce Leidl 2018-03-07 20:04:20 -05:00
parent 9ca3268be0
commit 3e9c676a93

View File

@ -2,9 +2,35 @@ Application Image Builder
=========================
Application Images (or appimgs for short) are created with this builder
framework. The build is controlled by a configuration file and this
configuration file is actually a shell script that follows the conventions
described in the Configuration File section of this document.
framework. The build is controlled by a configuration file which can customize
the build process in various ways such as adding extra packages and specifying
shell functions to be run at certain stages.
The configuration file is really just a shell script but it should follow the
conventions described in the Configuration File section of this document.
The builder bind mounts a package cache directory into /var/cache/apt of the
chroot so packages will only need to be downloaded once no matter how many times
you repeat the build. As a nice consequence of this the cached packages don't have
to be removed from the final image because they are merely unmounted when the
process completes.
Unless you disable it with a command line option, a tmpfs will be mounted on the
directory the rootfs is built on.If you are tweaking a config and making repeated
builds this is not only a lot faster, but will also avoid hammering SSD drives with
excessive writes (and write amplification).
By default the application image builder is self-hosting and can always be
run from inside images that it creates. Building an image is as easy as:
mkdir work && cd work : Make a directory to work in
appimg-builder --new : writes a template file build.conf in current directory
vim build.conf : (optionally) make some changes to the template
sudo appimg-build : Build an application image
If you want you can even skip the steps of creating and editing a config file and
just run appimg-build in a work directory and it will build the default appimg we use
with Citadel.
Stage One
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