An Azure Container Service helps you to create, configure, or manage a cluster of VMs. These clusters are preconfigured to run applications in so-called containers.

OK; this is a complete answer, but we should nevertheless take a deeper look.

Let's start with a comparison between the two Azure IaaS offers. The following diagram shows you the classic Azure IaaS offer, or in other words, Windows or Linux VMs on Azure:

As you can see, the offer consists of the following two layers:

• The infrastructure in Azure data center
• The actual VMs

The area infrastructure is easily explained; VMs are an abstraction of physical hardware running on a server and turn one server into many servers. The hypervisor allows you to run several VMs on a single machine.

Now we come to the area VMs, each VM includes one or more apps, the necessary libraries and binaries, and a full guest operating system.

A VM can reach a size in the high GB range and can therefore be very slow when booting.

The following diagram shows you the new Azure IaaS offer, or in other words, the IaaS based on a container solution:

At first glance, this diagram looks like the first diagram. But there are some differences.

In the infrastructure layer, for example, you will find a container engine instead of the hypervisor. In Azure Container Service, the container engine is a Docker Engine. Docker is currently the leading open source project for container solutions.

Let's come back to the subject. The container engine is the runtime environment for containers (partially comparable to the guest OS of the VMs). With their help, multiple containers can run on the same machine and share the OS kernel with other containers that run as isolated processes in their own user space.

The next difference in the new offer, you will find in the provision of the necessary libraries and binaries. They are provided by the container engine in an intermediate layer for individuals or as a shared resource for multiple containers.