Containers… Docker… What’s all the fuss about?

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You are here:Containers… Docker… What’s all the fuss about?

No Doubt you’ve heard many of the major companies offering cloud based services, going crazy and throwing around buzz words like Docker, CoreOS or Containers; in fact Microsoft has announced it will be integrating containers in their upcoming Operating System, Windows server 2016. Indeed containers really have become the hot topic of discussion recently.

 

But what exactly are containers and why should you care?

 

I’ll attempt to answer this questions within this post; we’ll explore the basic concepts of  the Containers technology and their benefits.

 

Containers have recently been made popular through the Docker Platform, which was released over 2 years ago. It would be easier to explain containers if we compared them to Virtual Machines, which no doubt many of you, have worked with by now.

VM Environment

In a virtual machine environment you usually have the following:-

  • A Physical Machine running a Hypervisor (like VMware ESXi or Hyper-V).
  • On top of the Hypervisor would be various virtual Machines running their own Operating systems with their own applications and Libraries.

 

Let’s compare this to how Containers are utilized.

Containers1

  • There is no Hypervisor needed
  • Each container is running its own isolated application code (It can run multiple applications)
  • Each container is not running its own OS, but is very much separate from the other container much like how VMs operate individually from each other.

 

Rather than virtualising a machine, a container is a virtualised OS, in fact another term for a container is Operating System Virtualisation. You see containers share the OS files of the underlying host, meaning OS files needed by an application within a container are always present. This is a great environment for developing and testing applications prior to pushing it out into a production environment. Also there’s the added benefit of the container starting up almost instantaneously as there is no need to boot and load the kernel or OS into ram as it is already there and also has a smaller footprint in memory, unlike a VM. The only draw back (if you can call it that) is the container can only have the same operating system as the host OS.

 

Containers have actually been available on the Linux OS for a very long time , implemented in a variety of ways. The main focus of containers is isolation; that is, the operating system provides a virtualised location in memory (known as a namespace) for the container, where it can only see the resources given to it. Resources can be anything from processes, applications, available network ports and file systems (there are many more). The container is made to think it has its own OS and hardware to manipulate.

 

Like a VM an administrator is able to configure the amount and type of resource each container actually uses.

 

There are new possibilities that can be carried out that containers introduce in the data center, many of the big platform vendor including Microsoft, Google and VmWare are introducing this technology into their platforms, and no doubt many data center  worldwide will be looking into taking advantage of this as well.

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