Slicing the Server: Hardware Virtualisation(VM) vs. OS Virtualisation(Containers)

#Docker Containers (OS Level)

• Boundary: Docker Engine (using Linux Namespaces and Cgroups).
• Architecture: Containers share the Host OS Kernel. They only package the Application and its specific dependencies (Bins/Libs).
• Result: Near-zero overhead and sub-second startup times.

#When to use which?

Choose VMs when: You need to run a different OS (e.g., Windows on Linux), require strict regulatory hardware isolation, or are running a massive stateful monolith.

Choose Docker when: You are building microservices, need to scale horizontally in seconds, or want a consistent environment across Dev, Staging, and Production.