Docker In Action -- Notes

1 Docker containers don't use hardware virtualization. Programs running inside Docker containers interface directly with the host’s Linux kernel. Because there’s no additional layer between the program running inside the container and the computer’s operating system, no resources are wasted by running redundant software or simulating virtual hardware. This is an important distinction.

2Understand that the running state of a container is directly tied to the state of a single running program inside the container. If a program is running, the container is running. If the program is stopped, the container is stopped. Restarting a container runs the program again.

3Docker doesn’t provide container technology; it hides the complexity of working directly with the container software.

Container:

The orphan volume problem can make disk space difficult to recover. Use the
-voption ondocker rm to avoid the problem.

■The volume container pattern is useful for keeping your volumes organized
and avoiding the orphan volume problem.

■The data-packed volume container pattern is useful for distributing static contentfor other containers.

■The polymorphic container pattern is a way to compose minimal functional
components and maximize reuse.

Container Network:

Docker provides four network container archetypes: closed containers, bridged
containers, joined containers, and open containers.