Essential mapping between Apple HomeKIt and OpenHAB2 is done via the Node-RED homebridge-openhab2 plugin (https://www.npmjs.com/package/homebridge-openhab2). This will map any OpenHAB2 ''Items'' decorated in the .items files into the HomeKIT space. The HomeBridge setup is essential since HomeKit can only deal with 99 accessories. Since HomeBridge is a bridge, it only counts as one.
Additional mappings of devices that have troubles with OpenHAB + HomeKit bridge can be added as separate HomeKit devices in Node-RED and hitched up to OpenHAB via the OpenHAB2 ''node-red-contrib-homekit'' plugin. To install, first look here: https://www.npmjs.com/package/node-red-contrib-homekit . However, the install needs a small modification, basically run:
<pre>
> sudo apt-get install libavahi-compat-libdnssd-dev