- agile in increasing resources
- elastic scaling
- fault tolerance

- AWS Management Console
- CLI(Command Line Interface)
- SDK (Software Development Kit)

	- Elastic Compute Cloud
		Compute - Compute or server resources  like web  / db  / mail / media server etc.
		elastic - increase or decrease resources
		
	- How to launch an EC2 instance
		- Search for EC2 in the service
		- Click Launch Instance
		- Choose the type of server needed - Linux / Red hat / Windows etc.
		- Then choose instance type - cpus/ memory needed etc
		- Configure Instance - like number of instances needed etc.
		- Add Storage - root storage , EBS additional storage 
		- Add tags eg : for uniquely identfying the instance 
		- Configure security group eg : type of access needed lik http on which port, ssh on which port. 
		
	- Download Putty to ?
		- Session Host Name 
			- default user  + @ + public DNS
			- [email protected]
		- SSH > Auth > Open (need to generate ppk file if it's not yet generated. Steps are describe below)	
			- Putty on Windows require ppk file, so need to generate that using the puttygen
			- Open PutyGen 
				- Then click load and select the .pem file downloaded when creating the EC2 instance. 
				- then click save private key 
				- this will save it as a ppk file. 
		- then use that ppk file in the putty

	- storage needed for the EC2 instances
	- volumes can be HDD / SSD
	- designed to be durable and available 
		- ssd - 
		- hdd - 
		- magnetic - for logs etc
	- can have encryption too 
	- can change from hdd to ssd 
	
	to attach a volume to an instance	
		- it must be in the same availability zone eg: us-east-1b
		- click volume > create volume > put the same availability zone as the instance > then click create volume 
		- click on volume > actions > attach volume > 
			> find instance > device = /dev/sdp
	connect to an instance
		- instance > select instance > connect 
		- then connect using putty - steps are described above
		- lsblk - to list all the block storage volumes
		- mke2fs /dev/xvdp - to create a folder (if there is super user issues type - sudo !!)
		- sudo mount /dev/xvdp /mnt mount folder 
		- cd /mnt to move to mnt folder 
		- ls - to list the files
		- vim file.txt ":q!" to save and exit
		- mkdir folder - to create a folder
		- mv fie.txt folder/ - to move to file.txt to folder
		
	detaching volume 
		- select volume > Actions > detach volume

	- simple api to storing and retrieving data
	- put as many objects. can be even have millions of requests per objects
	- store images / videos / server logs or event db snapshots
	- low latency period due to the http / https requests
	- use s3 privately through a virtual private cloud. 
	- can control using IAM to decide who can see data. 
	- by default all the data are stored privately 
	
	- how are the files saved ? 
		- Save files as key and object 
			- it's good practice to store key as file path eg: media/welcome.mp4
	- what happens when you create a bucket ? 
		- when you create a bucket it's stored in multiple facilities in the selected region.
		- grow automatically 
		- automatically scale 
	- how to access S3 ? 
		- CLI
		- Console 
		- SDL's
	
	- s3 names must unique and DNS compliant 
	- Common use cases 
		- can be used to save user generated file 
		- static web hosting
		- back and disaster recovery
		- storing area for big data... 
		
- how to create bucket ? 
		- click s3 > Create Bucket > enter bucket name > click create 
		- simply upload any file from your local storage. 
		- DOWNLOAD Amazon CLI to add data 
			- aws --version to make sure that it's installed successfully. 
			- C:\Program Files\Amazon\AWSCLI - default location of the CLI installed if it's x64 version. 
			- aws configure - to connect to AWS service
				- generate the aws access key id & access key 
			- aws s3 ls - will list all the s3 buckets
		- Creating a txt file using powershell
			- new-item file.txt - file will be created
			- set-content file.txt 'file content'  - will set the file content
			- get-content file.txt - will get the file content. 
		- how to copy a file from local storage to S3 using CLI?
		- aws configure to connect to AWS
			- AWS Access Key ID :  AKIAZ3ZMVABJG5BLCMWD
			- AWS Secret Access Key :  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
			- aws s3 cp file.txt s3://amazing-bucket-name/hello.txt : to upload the file.
			- aws s3 sync ec2 s3://amazing-bucket-name/files : to sync a folder
		- how to access the s3 bucket contents in the EC2 instance 
			- connect to EC2 instance using putty 
			- aws s3 ls s3://amazing-bucket-name --recursive : to see all the files
			- aws s3 cp s3://amazing-bucket-name/hello.txt . : to download the local Ec2 instance 
			- cat hello.txt : to see the contents of file
			- aws s3 sync s3://amazing-bucket-name/files folder : to sync from s3 to Ec2 instance 

	- can be broken down into 3 topics 
		- Regions - Geographical areas  that hosts 2 or more availability zones.
			- which region - optimize latency while minimizing costs & adhering to regulatory requirements
			- can also deploy resource to  multiple regions depending on the needs.
			- resources are not automatically replicated to different regions 
			- not all services are available in all regions
		- Availability zones : collection of data centers in a specific region 
			- each availability zone is physically isolated from the others
			- but connected by fast low latency network
		- Edge location : hosts the CDN(Content Delivery Network) / amazon cloud front
			- cloud front is used to deliver content to the customers
			- request for content are automatically routed to the nearest edge location. 

	- private, virtual network in the AWS cloud
	- VPC will also acts like a own premise network.

	- act like a built-in firewall for virtual service 
	- how to add a web security group ? 
		- Security groups > create security group > add name, description , http, https