Original subtitles

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So as we said before, the unscientific definition of cloud is compute, networking, storage and other

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services managed by someone else.

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But actually there is a more formal definition of cloud.

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And this definition comprised of the five characteristics of cloud computing.

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And these characteristics are on demand self-service road network access, resource pooling, rapid

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elasticity and measured service.

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So let's go through these characteristics and explain exactly what is each one of them.

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And let's begin with the on self-service.

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What is basically means is that no human interaction is needed for resource provisioning.

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That means that if I need a new virtual machine or VM, I don't need to send an email to someone or

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to pick a phone and talk to someone.

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I can do that with a click of a button.

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I just go to some Web app, define exactly what I need, click the create or next or add or something

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like that.

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And after a few minutes I will get my virtual machine.

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I don't need to speak with anyone in order for that to happen.

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Now this provisioning is available 24/7, which made possible by the fact again, that I do need to

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speak to anyone.

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Everything is automated.

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So that is the On-Demand Self-service Road Network.

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Access means that resources that I create in the cloud can be accessed from anywhere using the network.

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So I can, for example, create a virtual machine in the US and access it from my home in Israel.

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Now ideally that means that we have high broadband because I really need a good network and high bandwidth

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in order to access the resources that are just created on the other side of the world.

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In addition, no physical access is required at any time.

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So at no point in time do I need to access the physical host machine, either data center to perform

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some maintenance or to check things or maybe to take cables or anything.

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I don't need and actually I can't have and I'm forbidden to have physical access to this resource.

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The next characteristic is resource pulling.

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No resource pulling means that physical resources are shared between customers.

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So if I have a huge Hosta machine and I create a virtual machine on it, then it's very possible that

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other customers, which I have no knowledge of, also will use this very same machine to create their

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own virtual machine.

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In no way and in no time will they be able to contact these customers.

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I will have no idea who the customers are and of course I won't have any access to their resources.

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But still, the physical resources might be shared.

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The cloud backbone decides which physical resource to allocate for a customer's virtual services.

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So in most cases, I don't have any control and I can't decide which exact or specific cost machine

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do I want to use.

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This is up to the cloud backbone or the control center of the cloud.

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It is the one who make these decisions.

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Now, some advanced cloud services allow for physical resource separation, mainly for security reasons.

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Some services, for example, allow us to define that this service is going to be created on a separate

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physical host.

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They still do not allow us to select which host to use, but we can still define that.

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We want to use a separate host.

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Of course, these services are considerably more expensive than the usual ones, but still it's possible

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and it's up to us to make this decision.

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The next characteristic is rapid elasticity, and that means that resources can be scaled up and down

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as needed automatically.

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So if you remember the example that we discussed earlier about the electric job, then if we had this

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capability of scaling up and down and helping our two service to become four on November and then back

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to two on December, then that would be great.

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And this is exactly what the cloud enables us.

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There is no need to purchase resources for a one time peak scenario again, which was the exact problem

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we had in our example.

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And this is one of the most important capabilities of the cloud in one of the great motivations of all

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premise organizations to move to the cloud.

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As we will see later in our own example, this works rather well, and the last characteristic is misfold

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service.

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Mission service means that the payment is done only for resources actually used.

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So that means, again, that if I decide to use, let's say, two virtual machines, then I pay only

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for those two virtual machines.

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If later I.

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Another one, then I will pay for this one also, and if after that I decide to shut it down, then

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at this exact moment I stop paying for it.

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So some examples for how to measure the service we use is, for example, paying for Silvertown, which

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is the example we just discussed, DBI storage, where we pay for the storage we use in a database function

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calls, which we will discuss later and so on.

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So basically, as you can see, we pay only for what we actually use.

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The measurement usually done in high resolution, for example, server time is measured by the second

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and not, for example, by the hour or by the day.

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And the very important bottom line here is that we do not need to invest money in unused resources.

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So these are the five characteristics of cloud computing.

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And I hope that by now you understand better.

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What are the advantages of using cloud and how it can help you use your resources more efficiently and

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effectively.