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All right.

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So let's get started with this course.

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And I would like to start with a definition.

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Kubernetes is container orchestration system.

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Using Docker, you could, of course, create container on any computer.

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But of course, if you want to create multiple containers on different computers, on different servers,

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you could get into the troubles.

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Kubernetes allows you to create the containers on different servers, either physical or virtual, and

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all of that is done automatically.

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Without your intervention.

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You just tell Kubernetes how many containers you would like to create based on specific image.

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Kubernetes is relatively long world, and it consists of ten different letters, but IT professionals

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and software developers are relatively lazy people and they don't like to type much.

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That's why such a long word is usually shortened just to three characters.

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But how is it done?

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Let's have a look at this word between K and S.

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There are actually eight different letters.

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So number eight, that's why long word Kubernetes could be shortened just to three characters.

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k8s so eight represents simply quantity of the letters between starting and end in a letter.

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Simple as that, knowing this very simple trick, we could go on.

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And now let me explain to you what Kubernetes takes care of.

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So Kubernetes takes care of automatic deployment of the containerised applications across different

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servers.

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And those servers could be either bare metal or physical servers or virtual servers.

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Virtual servers option is, of course, more common nowadays, and almost no one uses now bare metal

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servers.

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So Kubernetes allows you to perform automated deployments across different servers that could be located

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even in different parts of the world.

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Other than that, Kubernetes also takes care of distribution of the load across those multiple servers,

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and this allows you to use your resources efficiently and avoid underutilization or overutilization

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of the resources.

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Also, Kubernetes takes care of the outer scaling of the deployed applications in case you need to increase,

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for example, quantity of the containers which have to be created on different servers and all of that

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done automatically.

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You just tell when you want to scale up or down.

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Also, Kubernetes takes care of the monitoring and health check of the containers.

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And in case some containers fail, for some reasons, Kubernetes could automatically replace failed

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containers.

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And all of that done without your intervention.

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As I just told you, Kubernetes deploys containerised applications, and therefore it has to use specific

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container runtime.

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And Docker is just one of the possible options.

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Kubernetes nowadays supports such container runtimes, docker, cry O and container db and such container

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runtime, for example, as Docker or O must be running on each of the servers which are included in

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the Kubernetes cluster.

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And main outcome here is that Kubernetes could be utilised even without Docker at all.

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It supports other container runtimes like cry O and container D, and at the end of this course I'll

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demonstrate to you how to change container runtime and move from Docker, for example, to cry o.

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So now let's get started with terminology and architecture of Kubernetes, and let's start with port.