Containerization uses the kernel on the host operating system to run multiple root file systems.  Each root file system is called a container, each container also has it's own processes, memory, devices and network stack. For more on Containers, see my Containers 101 post. As mentioned in that previous post, Docker has built a very strong ecosystem and simple way of consuming and using containers.  Let's take a look at a couple basics for docker and work from there. 

What are Containers? 

Containers are an OS-level virtualization method in which the kernel of an operating system allows for multiple isolated user-space instances, instead of just one. The primary benefits of using containers include limited overhead, increased flexibility and efficient use of storage; the container looks like a regular OS instance from the user's perspective. Changes to the image can be made very quickly and pushed to a repository to share with others for further development and utilization. 

The very idea of 3rd Platform is disruptive to the majority of IT shops because it is a radical paradigm shift that transitions from a device centric to a solution orientated approach.  

While the 1st platform was designed around mainframes and the 2nd platform was designed around client-server, the 3rd platform is designed around the cloud. In other words, applications are designed and built to live in the cloud. We can e ectively think of this as pushing many of the core infrastructure concepts (like availability and scale) into the architecture of the application itself with containers being a large part of this; they can be thought of as lightweight runtimes for these applications. With proper application architecture and a rock solid foundation either on-premise or in the cloud, applications can scale on demand, new versions can be pushed quickly, components can be rebuilt and replaced easily, as well as many other benefits discussed below.