Day 1.1: Cloud Concepts
Tags: aws, cloudpractitioner, cloud, beginners
Published: 2024-01-07 06:34:51


|**What is Client-server model?**|
|---|
|In computing, Client is web browser and server is any virtual services like Amazon EC2.
Example: You went to coffee shop. There barista is the server and you are the client. You(Client) make a request of you preferred coffee and the barista(server) evaluates the details of your request and fulfills it.|



|**What is cloud computing?**|
|--|
| **_<u>Def </u>_**: The On-demand delivery of IT resources over the internet with pay as-you-go pricing.
|"_On-demand delivery_" : AWS has resources you need when you need them. you don't need to inform the AWS in advance. you can just demand when ever you need by just few clicks and launch.
|"_IT Resources_" : AWS has many products. AWS wants to help you in tasks that are common and often repetitive, time consuming by providing its resources.
|"_Over the Internet_" : You can access the resources using a secure webpage.
|"_pay as you go pricing_" : why pay for developer environments for example on weekends if your developers aren't working! So you can pay only for what you use.
|Examples: Gmail, Netflix are some of the daily used cloud services



**<u> Deployment models of Cloud Computing </u>:**

|Public cloud(cloud based)| Private cloud(On-premises)| Hybrid cloud|
|--|--|--|
|Operated by third party cloud service provider| Used by single organization| Combines elements of both public and private clouds and allows data to be shared between them|
|Like using a public library. You access books(services) provided by the library(AWS) that anyone can use.| Like your book collection at home. Your books(services or resources) are exclusive to your use and not shared publicly.| Having both a personal book collection at home and using public library. You mix and match resources using some private and public based on your needs.|





|**<u>_Characteristics of Cloud Computing_</u>**|
|--|
|<u>1.On Demand self service</u>: Instant access to resources as-needed. Like ordering pizza when hungry.
|<u>2.Broad network access</u>: Access services from anywhere, anytime. Like accessing social media from various devices.
|<u>3.Resource pooling</u>: Shared resources for efficient utilization. Like sharing one vehicle for better efficiency(uber, rapido..etc)
|<u>4.Multitenancy</u>: Multiple users sharing resources. Like different families sharing a vacation house.
|<u>5.Elasticity and measured services</u>: Flexibility and Pay-as-you-go model. Like paying for electricity based on usage.|




|<u>_**Cloud Service models:**_</u>|
|--|
|1.**<u>Private cloud</u>**:  You own secured cloud environment Like a private office space.
|2.**<u>IaaS(Infrastructure as a service)</u>**: Basic infrastructure like virtual machines are provided and you manage everything else. Like a renting fully furnished apartment.
|3.**<u>PaaS(Platform as a service)</u>**: Platform provided with tools and services to build and deploy applications without managing infrastructure. Like renting a kitchen in a restaurant: focus on cooking not on infrastructure.
|4.**<u>SaaS(Software as a service)</u>**: Ready to use software applications. Like Facebook, Emails where you don't need to install software; you are just a consumer.| 


>**<u>AWS Public and Private services:</u>**

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/n25bhvw4xku8pbjavot5.png)

|**<u>Six Advantages of Cloud computing:</u>**|
|--|
|(1). **Trade fixed expense for variable expense**: Instead of making upfront investments in data centers and servers, cloud computing allows you to pay only for the computing resources you consume.|
|(2). **Benefit from massive economies of scale**: Cloud providers like AWS serve a vast number of customers globally. When many customers use the cloud services, the overall cost per unit decreases. This benefits the users who pay for computing resources on a pay-as-you-go basis.|
|(3). **Stop Guessing Capacity**: No need for upfront capacity decisions as users can access the required capacity as needed in mintues. So there is no limited capacity.|
|(4). **Increase speed and agility**: Cloud computing provides quick access to new IT resources. This increase in speed enhances organizational agility, making it easier and faster to experiment, develop, and deploy applications.|
|(5). **Stop spending money running and maintaining data centers**: Allows organizations to focus on customer-centric projects instead of managing the infrastructure.
|(6). **Go global in minutes**: Deployment of applications in multiple global regions with minimal effort.