Benefits of Kubernetes | Scalability, High Availability, Disaster Recovery | Kubernetes Tutorial 16

so kubernetes is an orchestration tool which means that if you have a complex application made up of multiple containers kubernetes tool will help you achieve high availability scalability and disaster recovery of your application setup but what does all these things actually mean and how does kubernetes help you achieve all of these things in order to answer these questions we're gonna go through a simplified visualization how kubernetes cluster really works so first let's talk about high availability and scalability here let's say we have two worker nodes of kubernetes cluster server one and server two with each server holding a replica of my application and a database application and we also have an ingress component which basically handles every incoming request to your application so if someone accessed my app website on a browser the request would come in to ingress an ingress component will actually be their own parts on each server so they are replicated as well so now when a user visits my app website on browser a request is made and handled by ingress first and as we just saw ingress is load-balanced so we have replicas of ingress on multiple servers ingress will then forward that request to a service for my application and service is a load balancer as well that will then direct that request to the respective replicas of the pot if let's say for that request a database access was necessary my app will then make another request to database service which is also load balanced and pass a request to one of the replicas and of course this is a simplistic view you can have 10 servers and 10 replicas of your database my April ingress applications but what this setup demonstrates is that from entry point of the request into the cluster til the last end point which is a database every component is replicated and load-balanced which means that in this whole setup there is no bottleneck where a request handling for example could stop the whole application and make the responses slower for a user but of course it must be noted here that your application or the way your application is designed should also support this replication and request handling because this is just tools that kubernetes offers you to make your properly designed application highly available in highly scalable so with this setup if server 2 completely crashed and all the parts that are running on it died you would still have replicas of your application running so there will be no downtime and in the meantime a kubernetes master process called controller manager would actually schedule new replicas of the died pods on another worker node let's say server 3 and recover the previous load-balanced and replicated application state which means while the node servers actually do the work of running the applications the master processes on the master nodes actually monitor the cluster state and make sure that if a pod dies it automatically gets restarted or if something crashes in the cluster that it automatically gets recovered an important master component that is used to manage the cluster mechanism to run properly is the Etsy D store which stores the cluster state like the resources available on the notes and the pod state etc at any given time so for example if a pod diet and it CD so would be updated about it and that's how the controller management would know that it should intervene and make sure new pot gets restarted so when that happens again it CD store gets updated and because etsy D always has the current state of the cluster it's also a crucial component in disaster recovery of kubernetes clustered applications and the way disaster recovery mechanism can be implemented how kubernetes is to create debt CD backups and store them into remote storage and these backups are in form of 8 CD snapshots now kubernetes doesn't manage or take care of baking updated CD snapshots on remote storage this is responsibility of the kubernetes cluster administrator so this storage could be completely outside the cluster on a different server or maybe even cloud storage an important note here is that HCD doesn't store database or application data that data is usually also stored on remote storage where the application thoughts actually have reference to the storage so that they can read and write the data from and this remote storage just like the HDD snapshots backup location isn't managed by kubernetes and again must be reliably backed up and stored outside of the cluster this is usually how production clusters are set up so now considering a reliable backup and replication of HDD snapshot and application data is in place if the whole cluster were to crash including the worker nodes and the master nodes themselves it would be possible to recover the cluster state on completely new machines with new worker nodes and also new master node using the HDD snapshot and the application data and of course you can even avoid any downtime between the cluster crash and a new cluster creation by keeping a backup cluster so to say that can immediately take over when the active cluster or the current cluster crashes or dies there is one thing I should note here you can actually achieve this setup with load balancers and replicas also without kubernetes for example on AWS instances using the AWS load balancer etc however there are a couple of advantages that you have with kubernetes that you don't have with other tools or if you would create this setup yourself one is the replication is made much easier using kubernetes the only thing that you have to do is just declare how many replicas of a certain application beat your own application or a database application you need and the kubernetes component takes care of actually replicating it second one is the kubernetes self-healing feature so what it basically means is that if a pod dies there should be processed that monitors the state that detects that a replica died and automatically restarts a new one and again you have this feature out of the box from kubernetes third is smart scheduling feature of kubernetes which means that for example if you have 50 worker servers that your application containers will run on with kubernetes you don't have to decide where to run your container you just say you need a new replica of a pod and kubernetes smart scheduler basically goes and finds the best fitting work node among those 50 worker nodes maybe to schedule your container by comparing how much resources a worker node has available or free and overall many features that you could also do elsewhere on other platforms like as I mentioned AWS is made simpler or it's easier to create and configure in kubernetes like service as a load balancer for example thanks for watching the video I hope it was helpful and if it was don't forget to like it this is a video series so I will create a new one every week so if you want to be notified whenever and you comes out then subscribe to my channel if you have any questions if something wasn't clear in the video please post them in a comment section below and I will try to answer them so thank you and see you in the next video

Channel: TechWorld with Nana

Views: 23,101

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Keywords: what is kubernetes, kubernetes explained, what is kubernetes for dummies, what is kubernetes used for, why kubernetes, how does kubernetes work, kubernetes tutorial, kubernetes tutorial for beginners, kubernetes for beginners, kubernetes explained simply, kubernetes concepts explained, kubernetes basics, kubernetes basic concepts, kodekloud, kubernetes high availability, kubernetes scalability, kubernetes disaster recovery, kubernetes benefits, techworld with nana, k8s

Id: g8Sf-6EsgZM

Length: 8min 52sec (532 seconds)

Published: Sat Jan 25 2020