file that brings this in iotdm:
https://github.com/opendaylight/iotdm/blob/master/onem2m/onem2m-protocols/http/src/main/java/org/opendaylight/iotdm/onem2m/protocols/http/Onem2mHttpProvider.java#L41

file in controller:
https://github.com/opendaylight/controller/blob/master/karaf/opendaylight-karaf-resources/src/main/resources/configuration/tomcat-server.xml#L29

when loading the feature odl-iotdm-onem2m, there will be a port conflict.