For people playing along at home, with https://git.opendaylight.org/gerrit/48415 and https://git.opendaylight.org/gerrit/47884 we can now get a Karaf 4-based distribution which starts correctly. Once it's started,

feature:install wrap

will load the pre-requisite "wrap" feature, and feature:install will then load ODL features as usual. Things currently fall over with bundles providing CLI commands since the Felix bundles have changed.

(In reply to Vratko Polák from comment #5)
> One approach would be to start developing karaf4-parent as an experimental
> functionality, and only replace karaf-parent with the new implementation
> when it becomes stable enough. The upside is that we can gradually implement
> CSIT jobs and open Bugzilla items, without the need to get everything right
> in a single Change.

I like this a lot. I've started https://git.opendaylight.org/gerrit/47484 (draft, ask me if you want to review it) which currently provides the default upstream Karaf 4 via karaf4-parent and opendaylight-karaf4-empty. Subsequent patch sets will align the resulting Karaf distribution with the requirements currently implemented in karaf-parent and opendaylight-karaf-empty.

There may be multiple changes to be applied to karaf-parent in order to make it work correctly with Karaf 4, especially around the things karaf-plugin does.

One approach would be to start developing karaf4-parent as an experimental functionality, and only replace karaf-parent with the new implementation when it becomes stable enough. The upside is that we can gradually implement CSIT jobs and open Bugzilla items, without the need to get everything right in a single Change.

I would recommend to leave karaf-plugin out of initial karaf4-parent commits, and attempt to employ "assembly" goal of karaf-maven-plugin instead. And introduce karaf4-plugin only if it is still needed at the end.

> karaf-4.1.x, due to the fact that they bundle sshd-core-0.14.0 as a startup feature

In karaf-parent, there already are workarounds for org.apache.karaf.region.persist, org.apache.aries.proxy.impl and org.apache.servicemix.bundles.xalan-2.7.2_3, so I believe karaf-4.0.x could be made to work as well.

BUG-6318 requires karaf-4.1.x, due to the fact that they bundle sshd-core-0.14.0 as a startup feature in versions prior to that.

This is a gating issue for https://bugs.opendaylight.org/show_bug.cgi?id=3973