in the first episode we'll be talking about what cloud computing is but also what is the most important vocabulary that you should understand when working with cloud in general it both describes what cloud computing is but also what are its benefits stay tuned let's look at the objectives of the first episode today we'll learn what cloud computing is but also what are its benefits by learning the most important vocabulary like high availability scalability elasticity agility fault tolerance and also disaster recovery let's start with cloud computing while computing is a delivery model for services services like
storage services as whenever you're storing your unstructured or structured data in files and databases while delivers you thousands of services to do so you pretty much can choose any technology that is popular in the market and you will be able to use it with an ear harsher environment in this case storage doesn't only mean storing data but also all the services and tools that allow you to migrate your data to the cloud once your data is in the cloud you will need a computer resources like a Windows virtual machines maybe a Linux ones web containers
or any of the hundreds of services available in the cloud because cloud is about creating applications whenever those our web AI machine learning reporting any kind of applications out there additionally once you have your components you need to be able to somehow connect them to each other securely the cloud delivers you with said functionalities to create secure networking between those components but also your company and because your entire platform is managed in the cloud cloud also needs to deliver you of analytic capabilities so you can review your performance and telemetry data for your services you
can perform operations the list of the services delivered by cloud computing is much longer than this but those are the four main ones and four that are tested by the exam all of those services of course are delivered over the internet and this is basically what cloud is delivering services like this doesn't make a cloud computing yet now competing needs will also fulfill and characteristics first characteristic that we will learn today is scalability imagine you have a resource that resource can be anything it can be a web application it can be a database in can
be a virtual machine that gives you a way to scale up this virtual machine by increasing its size increasing size of the resource basically means adding more power like CPU memory or maybe faster storage in this case we are moving along the vertical line that's why this is called vertical scaling and increasing the size of the resource is called scaling up if you decrease the size decrease the power of the machine this is called scaling it down besides changing the size of your research changing the power of that resource you can also scale by adding
more resources to your environment so increasing the amount of the resources themselves in this case we are moving along the horizontal line that's why this is called horizontal scaling if you increase the amount of your resources this is called scaling out if you decrease the amount of resources this is called scaling in so to summarize scalability is an ability of the system to scale in this case scaling is a process of adding or removing resources remember that in this case resources might both mean d virtual resources like CPU memory but also a specific instances of
the resources or our next term we have elasticity one of the best ways to explain elasticity is to show the user workload off in the typical application during the day where the user workload changes as the day progresses if you design system like this you need to assign the specific amount resources to be able to handle the workload properly design system will be able to allocate and deallocate resources whenever needed if this process is done automatically we are talking about automatic scaling an automatic scaling is basically what elasticity is summarized elasticity is the ability of
the system to scale dynamically our next term is agility in the cloud there are two ways to provision resources either manually via portal or unabated ways using api's and scripting but regardless of what choice do you make both cases there's the time between the request is submitted and the response that the request has been fulfilled and the major difference between the cloud and on-premises is that requesting resources in on-premises environment usually takes days weeks or even months in cloud once you request the resource you will most likely get it within seconds or minutes and for
very few very big services this might take few hours but still this is a major difference between the on-premise environments in this case when we say agility we mean the ability to react quickly and in the cloud this means being able to allocate and deallocate your resources in very short time the next term on our list is so-called fault tolerance as a user you purchase services from the cloud whenever that's web application virtual machine or SQL but regardless of the service that you choose or the interface that you use that service with all those services
need to run on some sort of servers in a data centers storing their data on disk arise whenever there's any service or component failures on those servers were out on to be moved to another and same goes for discs arise your data is ultimately stored on multiple discs and multiple disk arrays to ensure no data is lost both tolerance in this case talks about the ability of the system to remain up and running during component and service failures so those localized failures will not interrupt your service most of the time in the cloud all the
services have built-in fault tolerance that means if you use cloud services you will not notice those localized failures affecting your system at all besides those localized failures an event of much greater scale might happen and even like this is called disaster disaster is a serious disruption of entire service caused by natural or human induced causes a scenarios of this level that we talk about are typically like floods earthquakes under storms power grid failures or human errors but they can affect entire arjun region or entire other servers from working properly in this case to do is
set up disaster recovery is aster recovery simply means creating two copies of the same application into our regions and then setting up replication between them so that you have two identical copies of your application then in front of those application you need to set up a simple DNS routing so that your users are automatically redirected to the working version of your application if any service fails they will automatically get resurrected till replicated version of your application so disaster recovery is system's ability to recover from even that has taken down entire region or service to simply
said it's a way for your system to work properly after a disaster and our last turn for today is so-called high availability availability is a simple metric that measures how much uptime of the system so the system being accessible to users or other systems versus how much downtime this system had in this case downtime means planned occurrences like system downtime for patching or unplanned so system failures and availability it's a simple calculation between the uptime and entire lifetime of the system and depending on what you agree with your client you calculate availability barrier month or
day using this metric is very important because ninety-nine percent availability means only three days of downtime per year if you go for free nights that's only eight hours almost nine hours per year of downtime but most companies targeting high availability they go for at least four nines which means fifty-two minutes per year with so restrictive uptime requirements you will need a specific tools and specific design in order to achieve high availability but in this case summarize availability is a measure of system uptime for either users or services and high availability basically means ability of the
system to run for very extended periods of time with very little downtime to things that I want to mention here is that one depending on the criticality of your system you need to choose whenever this system should be highly available or not but luckily for us in our many services deliver very high availability by default so just check what they offer and decide if the service is right for you next steps after watching this episode go to my website Marcia Gay Oh 8900 hashtag episode a1 and check out the materials that I prepared for you
especially check out the cheat sheet and practice tests to test your knowledge and that's it for this episode thank you guys for watching if you like what I do support the channel by subscribing liking and commenting or showing this to your friends if you want to see the next episode simply follow the playlist or hit the icon on the side and see you there [Music]
