With the proliferation of use-cases envisioned to be supported by 5G networks, the focus is not only on the performance, but also on the service agility and elasticity. Cloud native principal is a methodology of designing lightweight, isolatedcontext, and deployable at scale applications that natively exploit the features of cloud. However, supporting telco applications (e.g., 4G/5G services) in the cloud brings up many challenges, such as the coexistence of physical and virtual functions, (near) realtime resource provisioning, service continuity, and strict latency and data rates. In this paper, we propose Kube5G, as a realizable agile service platform in support of 4G/5G cloud native applications. Kube5G introduces a novel approach in building and packaging a cloud-native compliant telco network function (NF) in a form of nested well-defined layers. In addition, we present a workflow for continuous integration and development operations in support of multi-version network functions (physical, virtual and cloud functions). We also present a concrete prototype implementation of Kube5G with experimental results indicating its efficiency and highlighting user and network perceived performance.