Do you want to help combat climate change? Are you interested in sustainability research? Then join our open systems for Cloud-native sustainability infrastructure. We present the research opportunities of using Cloud-native patterns, observing, optimizing, and executing, to improve Cloud efficiency in sustainable architecture. Core to this architecture is Project Kepler (Kubernetes-based Efficient Power Level Exporter) and its integration with Kubernetes ecosystems. By leveraging eBPF programs and other system libraries, Kepler probes the full spectrum of energy, performance, and resource measurements to enable energy-relevant observability and further empower advanced sustainable management on clusters. Kepler is an open system for exciting research topics like energy-efficient workload scheduling, energy-aware autoscaling, and frequency tuning. In this session, a sample Kepler integration is case-studied to help researchers build their advanced vertical autoscaler to improve the energy performance objectives of the Kubernetes applications.