The next major release of the Pentaho Platform will include significant enhancements to OSGI support. Many of these features are in active development and may or may not make it in the next release. Those that do make it in may be modified from how they're described here.
BA / DI Servers
The Felix OSGI environment that shipped with 5.1 has been replaced by Apache Karaf.
Link to Karaf
List and describe Pentaho Features
New features provided by OSGI environment
PDI OSGI Bridge
Document how to provide Kettle plugins as OSGI Bundles
Spoon Karaf instance
Needed when not deployed in the platform.
OSGI Web Environment
RequireJS Servlet Bundle
JAX-RS from blueprint