The technology stack consists of the following four layers. 1. Maven: OpenDaylight uses Maven for its complete build automation, and its archetype has been used for setting up the initial project structure to develop applications. Java: The OpenDaylight framework is built in Java. Apache Karaf: This is a lightweight OSGi container for loading modules/bundles dynamically at runtime. YANG: OpenDaylight uses YANG for data modelling language, RPC and notifications between different modules. 2. 3. 4.