Fabric child container's initial properties should default to those of its parent

When a fabric child container is created, it gets a default set of properties – these are the files in etc/ in the newly-created child, and the profile properties that are created from these files and elsewhere.

Of particular concern are the settings of org.ops4j.pax.url.mvn.repositories and other properties that are related to configuration in a no-Internet environment. If these settings are incorrect, then the new child container starts in a non-functional state, needed a deal of manual intervention to correct.

At present, these properties are stored in a JAR file: org.apache.karaf.admin.core-XXX.jar in the system/ directory of the parent container. Editing them is awkward, and leaves the set-up in a state where supportability cannot be guaranteed.

It is proposed that these child container properties are derived from the parent container, in the expectation that the parent container will be set up correctly before the child is created. Alternatively, we might consider some sort of template mechanism, with properties in the template being used to initialize new containers.

In any event, we should review the mechanism by which child containers are configured, with a view to making it more flexible for customers.