 This is a series of two modules in we will discuss the cloud application design principles We will discuss 10 of those design principles and in this module. I will discuss the first five design principles of cloud applications. So what are those? Five first design principles you can see on your screen. You can read them The first of this design principle is the very famous quote by the chief technology officer of Amazon And let's now go into more detail. As per CTO Amazon, everything fails all the time IT departments have traditionally attempt to render both infrastructure and application impervious to failure A hardware resource or an application component that fell down on the job increase the urgency To search for perfection in order to banish failure Searching for perfection never successful never successful Unfortunately that search was never successful the failure of resources and application has been part of the IT world from the beginning Amazon starts from a different perspective. It's the world's largest online retailer and What they say when you run data centers containing thousands of servers and tens of thousands of disk drives resource failure is Daily occurrence Okay, so and when a hardware resource fails the software or data residing on that resource suddenly stops working or becomes unavailable One can't also cannot also rely on continuous functioning of software components or external services They fail to software components also fail an element of software package configuration or an unforeseen program execution path or an excessive load on an external service Means that even if hardware continues operating properly portions of an application can fail Can fail Okay, that's the single most important cloud application design principle is to accept that the perfect systems don't exist embrace failure Okay, rather than become frustrated by the state of affairs. You should recognize this principle and embrace it Having recognized that failure is inevitable be sure to adopt cloud application measures to mitigate circumstances and Insulate yourself from failure insulate yourself from failure Okay, so this is the point everything fails and all the time it is going to happen. Let's move on to the next Redundancy protects against resource failure Redundant resources pick up the load. So when you have multiple resources, right? A multiple hardest multiple processing units. So when some of those units fail There is there has to be an automated system which is monitoring all of this and it It distributes the load or assigns the load to those Elements to those devices which are working for example in the s3 case There are three copies of the data element. So if one disk drive or a setup fails Okay, then the second one is available Where the copy exists and of course q services spread across multiple machines which enable Degrade did which which enables preventing the degradation of the performance that is the key over here Okay, and these applications are cross connected to adjacent tiers that also against resource failure Launch new resources when left with single resource, of course, it may so happen if you have multiple resources And you say I had two resources and one resource failed Then in that case bring in the second resource so that that single resource has a resource to fall back which results in having something which is Against the failure that is the key over here Distribution protects infrastructure failure. Okay. Now what kind of infrastructure failure we are talking about Because now we are talking about the entire data centers being being failing Power outage natural disaster So what is going to be happening in that case? Having recognized the need to protect yourself against resource failure Whether it's hardware or software and you resolve to use multiple instances Okay, but that still doesn't help if a problem occurs at the higher level Such as the entire data center Entire data center can fail due to power outage due to natural disaster as you can see over here Okay, in that case you use redundancy at the data center level to avoid this problem Rather than run your application on multiple instances within a single data center You run those instances in different data centers different data centers Okay at two availability zones and those zones are located far enough understand And to be resistant to natural disasters So even if one is knocked off the air by a storm or an earthquake Another one remains operating so that you can continue to run your operation And availability zones are connected by high speed network high speed network To ensure that your application's performance doesn't suffer if it spends multiple availability zones So this is how to protect the infrastructure failure Monitoring prevents problem how to know redundancy field This cannot be done by humans because humans get bored. It is very expensive Okay, they need a break. So it has to be automated Now so these systems are self-monitoring systems. They generate the alerts And these alerts of course go to the administrator And these systems also take on and do Things at their own automated These things these systems can be connected together also So that not only the monitoring is automated, but the corresponding actions are also automated It's an unfortunate fact that many many amazon web services users fail to keep track of the resources they use Which can lead to underused or even unused resources Okay, they are not used but they are built This problem is significant because amazon web services continue to run up charges Even if the resources aren't performing useful work Okay, and how to avoid it? How should you avoid it? Use the amazon web services trusted advisor service or a commercial utilization And cost tracking services like cloud in Okay Design the application so that it can have individual resources added or subtracted so that the resource utilization rates stay high And resources don't sit around idle or lightly used Use amazon web services easy to reserve instance to reduce the cost Reduce the cost of the computing side of your application and finally regularly your amazon web services builds to see if there are resources applications being used Okay review the bills they are used That you don't know about and then go find out about them So that is all for these five design principles of cloud applications And in the next module we will look at the next five of those principles There's our fault this module. Thank you very much