Virtualizing MongoDB on Amazon EC2 and GCE: Part 1 discusses the pros and cons of virtualizing databases in cloud environments. Virtualization offers ease of management, agility, fast backup, and scalability, but also has overhead from the hypervisor and potential contention for resources between VMs. In contrast, bare metal provides dedicated resources without hypervisor overhead, customization, and lower costs over time, but requires longer provisioning times, snapshotting challenges, and CapEx upfront costs. The article highlights the trade-offs between cloud and bare metal infrastructure, with a typical trajectory being to start in the cloud and migrate to data centers once revenue is established.