README.c3_app_container

c3-app-container
-------------------------

The meta-cube layer comes with a single 'flexible' image called
'c3-app-container'. This image allows you to build a single
application container where you select the application which the image
will contain. Application selection is made via local.conf, by setting
'C3_APP_CONTAINER_APP' to the name of the application.


Building
-------------------------

The image is built using the normal bitbake commands:
%> bitbake c3-app-container

The output will be found in the tmp/deploy/images/* directory
alongside the other images.


Usage
-------------------------

You can use the c3-app-container as an artifact to the cubeit
installer but more likely you will install the image on a running
system. This would be done by copying the image tarball to the target
running OverC and then running the following commands on dom0 or in a
container with bindings to dom0:

# c3 add -n app-container c3-app-container-genericx86-64.tar.bz2
# c3 cfg -o /opt/container/app-container set app:/usr/bin/<your_app> [options]
# c3 start [options] app-container


Image size
-------------------------

The image size will depend on your selected application. As with any
image, bitbake will include any dependencies in the image and as such
the size can easily grow. A small application with no/few dependencies
will result in a image of only a few MB.


Creating more than one app container
-------------------------

The use of the 'c3-app-container' and 'C3_APP_CONTAINER_APP' is
restricted to one application. However, you may use the
c3-app-container.inc in your own image recipe in a similar way
c3-app-container_*.bb does. This will allow you to write your own
application container images in only a few lines, and, any
improvements made to the c3-app-container.inc will immediately be
available in your image.