Introduction to Docker
As we already mentioned in Chapter 2, Introduction to Spring Boot, Docker made the concept of containers as a lightweight alternative to virtual machines very popular in 2013. To quickly recap: containers are actually processed in a Linux host that uses Linux namespaces to provide isolation between containers, and Linux Control Groups (cgroups) are used to limit the amount of CPU and memory that a container is allowed to consume.Compared to a virtual machine that uses a hypervisor to run a complete copy of an operating system in each virtual machine, the overhead in a container is a fraction of the overhead in a virtual machine. This leads to much faster startup times and a significantly smaller footprint. Containers are, however, not considered to be as secure as virtual machines. Take a look at the following diagram:
The diagram illustrates the difference between the resource usage of virtual machines and containers...
