The past five years have been the warmest since records began. Human activity, including the IT industry, is driving worrying climate change. Data centres alone consume 2% of the world’s energy, and more and more of that energy is being used by Kubernetes and workloads running on Kubernetes. Is k8s helping, or making things worse? The beauty of the cloud is that it makes it easy to run code, virtualised and scheduled for efficiency… but it doesn’t provide any guarantee that what’s running is useful. Even when the workload is high-value and efficient, Kubesprawl can lead to low utilisation, unsatisfactory elasticity, and high costs – but mega-mono-clusters have their own problems around isolation, security, and management. How should these competing requirements be balanced? This talk discusses some of the trade-offs and provides a roadmap to figuring out the right thing.