Docker container daemon architecture

Containers are a simple and smart answer to the need to run isolated process instances. We can safely affirm that containers are a form of application isolation that works at many levels, such as filesystem, network, resource usage, process, and so on.

As we saw in Chapter 1, Introduction to Container Technology, in the Containers versus virtual machines section, containers also differ from virtual machines because containers share the same kernel with the host, while virtual machines have their own guest OS kernel. From a security point of view, virtual machines provide better isolation from potential attacks, but a virtual machine will usually consume more resources than a container. To spin up a guest OS, we usually need to allocate more RAM, CPU, and storage than the resources needed to start a container.

Back in 2013, the Docker container engine appeared in the container landscape, and it rapidly became very popular.

As we explained...