Network technologies are embracing the cloud-native paradigm, following the current best practices in cloud computing. Cloud-native technologies might be applied to different types of network functions in a mobile network, but they are particularly relevant nowadays for core network functions, as the recent standard introduces the Service-Based Architecture that matches modern cloud-native technologies such as Docker or Kubernetes. In parallel, a number of open source software initiatives already provide researchers and practitioners with usable software that implements the key functionality of a mobile network (both for LTE and 5G). These software solutions, however, are monolithic and not integrated into state-of-the-art cloud native frameworks. In this paper, we fill this gap by describing the implementation of a cloud-native mobile network, which supports channel emulation and provides an affordable and scalable way of testing orchestration algorithms with standardized VIM interfaces. Our experimental evaluation shows the applicability of our solution, which is released as open-source and illustrates its flexibility.