What is the difference between containerization using Docker and using a full virtual machine?

Docker uses containers that isolate applications at the operating system level, sharing the OS kernel with the host and other containers. This allows applications to run quickly and with minimal resource overhead.

A virtual machine (VM) emulates a complete hardware layer, including its own OS kernel, which requires more resources and time to start.

Main differences:

• Isolation: A VM is fully isolated, while containers share the OS kernel.
• Performance: Containers start faster and consume fewer resources.
• Size: Container images are usually much smaller than VM images.

Example:

# Running a Docker container
docker run -it python:3.9 bash

Unlike starting a VM, which requires loading a full OS.