With Horizon 18 we added support for sending OpenNMS events into Elasticsearch. Unfortunately, it only works with Elasticsearch 1.0. Elasticsearch 2.0 and higher requires Camel 17, but OpenNMS can’t use it. I wondered why, and if you were wondering too, here is the answer from Seth:

Camel 17 has changed their OSGi metadata to only be compatible with Spring 4.1 and higher. We’re still using Spring 4.0 so that’s one problem. The second issue is that ActiveMQ’s OSGi metadata bans Spring 4.0 and higher. So currently, ActiveMQ and Camel are mutually incompatible with one another inside Karaf at any version higher than the ones that we are currently running.

The biggest issue is the ActiveMQ problem, I’ve opened this bug and it sounds like they’re going to address it in their next major release

So there you have it.