A Docker container is a Linux sandbox that isolates processes using kernel features like namespaces and cgroups, allowing them to run directly on the host kernel with a restricted view of the system. Unlike virtual machines, containers share the host kernel and boot instantly with minimal memory overhead. Containers require a Linux VM to run on macOS and Windows since those kernels lack the necessary isolation mechanisms.
A detailed guide for migrating enterprise platforms from major cloud providers (AWS, Google Cloud, Azure) to dedicated servers in colocation facilities, targeting companies with ~$100k monthly cloud bills. The plan outlines 20 sequential moves across five stages—Decide, Buy, Build, Move, and Decommission—designed to minimize downtime while preserving operational capacity and reducing long-term infrastructure costs.