This chapter introduces hypervisors and virtualization, the core technologies that make cloud computing possible. We'll go deep into how virtualization works and how it protects your virtual machines and allocates computing resources. But we'll also touch on the security challenges and how providers are rising to meet those challenges. By the end, you'll have a good understanding of what virtualization means and how it protects your data. You'll understand the extra features you can look for in a hypervisor to increase your security profile and how you can configure your SAP system to make efficient use of flexible resources.