Over the last eighteen months, we have seen significant adoption of Hadoop eco-system centric big data processing in Microsoft Azure and Amazon AWS. In this talk we present some of the lessons learned and architectural considerations for cloud-based deployments including security, fault tolerance and auto-scaling. We look at how Hortonworks Data Cloud and Cloudbreak can automate that scaling of Hadoop clusters, showing how it can react dynamically to workloads, and what that can deliver in cost-effective Hadoop-in-cloud deployments.