Many times we hear the differences between Kubernetes and Docker. While at first glance they seem to be the same, allowing you to do similar things like allowing containers to run; however, both work in different layers of the Cloud infrastructure and more than competitors, we can say that between them, there is a “symbiosis” as they are actually two partners who can work very well together.
To understand exactly what each of these technologies is, let’s review some important concepts.
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Virtualization
With the concept of visualization come virtual machines – from now, we will call them VMs.
What are Virtual Machines? Basically, they are just computers that run inside another computer.
Sounds nice, but they have issues. The main problem is each VM’s weight since, within each VM, we have an entire OS, dependencies, etc.
Another problem presented by MVs is the issue of redundancy. When we have multiple VMs running within the same host, they usually repeat what they contain (OS, dependencies, etc.). They operate “isolated,” they do not share resources.
Also, they are often expensive to manage. Considering that each VM is a “machine,” you have to patch them security, updates, internal security between apps, etc.
Another disadvantage they present is the slowness to be able to test an application. You have to wait for the application to initialize and the time it takes to boot the VM itself.
Based on these “problems” presented by MVs, the concept of “containers” arises.
What are Containers?
Containers are groupings of processes that are isolated from the rest of the world. It is a closed package containing everything necessary for an application or service to run encapsulated within a single image, completely independent of the host server hosting it, including binaries, configuration files, and other files you need.
They can be compared to VMs, but they differ in some points. Starting with the weight, which unlike the VM, the containers are in the MB order, which makes them very versatile. They only run processes, not complete OS (which also makes them more efficient in terms of hardware resources consumption, compared to VMs). They work well anywhere. They are efficient, as they can share base files with other containers without the risk of them being altered or modifying the other, as they are immutable.
Once we have reviewed these concepts, we can ask ourselves:
What is Docker?
Docker is a system that allows to build, transform, deploy, and run the containers that contain applications in a very simple and reliable way, ensuring a scalable deployment efficiently regardless of the system host that contains them.
Docker provides a strong, robust, and portable system because everything our application needs (libraries and other dependencies) are encapsulated within the same container, ensuring that the container will be either the same way on any computer, server, or OS.
While Docker allows running containers and the management tools it provides may be sufficient to manage a single server, it is very impractical to use a large-scale montage of a distributed multi-container infrastructure running in hundreds of servers at the same time.
What are Kubernetes?
If you have Docker installed on a group of hosts (different operating systems), you can take advantage of Kubernetes. These nodes, or Docker hosts, can be servers or virtual machines. Kubernetes can allow you to automate container provisioning, networking, load balancing, security, and scaling on all of these nodes from a single command line or dashboard. A collection of nodes managed by a single instance of Kubernetes is called a Kubernetes cluster.
The development of Kubernetes is based on the previous experience of its programs in an internal Google project called Borg, which by its structure and philosophy of division of labor resembles the Borg collective of Star Trek. It is no coincidence that its code name for Kubernetes in its inception was Project Seven.
KUBERNETES AND DOCKER: WHY USE THEM?
The advantages of cloud services are many. From a technical point of view the cloud has the great advantage of being elastic, allowing to grow and decrease in resources according to the needs almost instantly. That ensures that you can accompany the increased workload by increasing resources and re-decreasing when no longer needed.
While Kubernetes supports several different types of containers, the most common and popular is Docker. In this perfect society that makes up both, Docker is responsible for creating the images and containers that are going to be Kubernetes manages everything.
Kubernetes and Docker both have the advantage of being open source. This is an advantage not only for an economic issue but because being open-source gives us the option to adapt it to our needs freely without being tied to the limitations of a license and the technical limitations we often face with a closed product.
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