Apache Karaf regarding its origins. Well to help answer this question I've written up this brief history of Karaf so that I may reference it.
In the beginning...
Apache Karaf can trace it's origins back to the Apache Servicemix project's Kernel. As early as 2008 the first blog posts regarding its development can be observed. The first GA release was on September 18th, 2008. The original release notes can be viewed here. Subsequent releases soon followed, introducing new features.
The Servicemix Kernel was off to a great start, eventually however by spring 2009 the project grew to the point that it was thought best to leave Servicemix and join it to the Apache Felix community. It was felt that this would allow awareness to grow about the project, and to expand the Kernel community. At this time the Servicemix Kernel project was renamed to "Karaf". For those of you interested about how the project became called 'Karaf' here is the relevant excerpt from the discussion:
"A carafe is a small container used for serving wine and other drinks (http://en.wikipedia.org/wiki/Carafe). In similarity to the name the Kernel allows applications to be more easily handled, and improves their characteristics (much like a bottle of wine left to breath in a decanter) :)"
So why the respelling? It was felt that 'Karaf' would be an easier search target, and it would fill the relatively empty 'K' project name listings at Apache ;)
Once established in the Apache Felix community Karaf again started to grow and mature, once again coming to the point that it was felt that another growth spurt was required - becoming a top level Apache project. This occurred mid 2010. Since then Apache Karaf has released it's first GA as 2.0, and several point releases and patches. The community is now busy readying the next major point release, and preparing for its future 3.0.