A Spot Instance is an unused EC2 instance that is available for less than the On-Demand price. Because Spot Instances enable you to request unused EC2 instances at steep discounts, you can lower your Amazon EC2 costs significantly. The hourly price for a Spot Instance is called a Spot price.  Your Spot Instance runs whenever capacity is available and the maximum price per hour for your request exceeds the Spot price.

Spot Instances are well-suited for data analysis, batch jobs, background processing, and optional tasks.

By default, there can be 100 S3 buckets in an AWS account

• You can create a maximum of 125 scheduled actions per Auto Scaling group.

AWS Regions and Availability Zones

Amazon cloud computing resources are hosted in multiple locations world-wide. These locations are composed of AWS Regions and Availability Zones. Each AWS Region is a separate geographic area. Each AWS Region has multiple, isolated locations known as Availability Zones. 

Region Name	Region	Endpoint	Protocol
US East (Ohio)	us-east-2	rds.us-east-2.amazonaws.com	HTTPS
US East (N. Virginia)	us-east-1	rds.us-east-1.amazonaws.com	HTTPS
US West (N. California)	us-west-1	rds.us-west-1.amazonaws.com	HTTPS
US West (Oregon)	us-west-2	rds.us-west-2.amazonaws.com	HTTPS
Asia Pacific (Hong Kong)	ap-east-1	rds.ap-east-1.amazonaws.com	HTTPS
Asia Pacific (Mumbai)	ap-south-1	rds.ap-south-1.amazonaws.com	HTTPS
Asia Pacific (Osaka-Local)	ap-northeast-3	rds.ap-northeast-3.amazonaws.com	HTTPS
Asia Pacific (Seoul)	ap-northeast-2	rds.ap-northeast-2.amazonaws.com	HTTPS
Asia Pacific (Singapore)	ap-southeast-1	rds.ap-southeast-1.amazonaws.com	HTTPS
Asia Pacific (Sydney)	ap-southeast-2	rds.ap-southeast-2.amazonaws.com	HTTPS
Asia Pacific (Tokyo)	ap-northeast-1	rds.ap-northeast-1.amazonaws.com	HTTPS
Canada (Central)	ca-central-1	rds.ca-central-1.amazonaws.com	HTTPS
China (Beijing)	cn-north-1	rds.cn-north-1.amazonaws.com.cn	HTTPS
China (Ningxia)	cn-northwest-1	rds.cn-northwest-1.amazonaws.com.cn	HTTPS
EU (Frankfurt)	eu-central-1	rds.eu-central-1.amazonaws.com	HTTPS
EU (Ireland)	eu-west-1	rds.eu-west-1.amazonaws.com	HTTPS
EU (London)	eu-west-2	rds.eu-west-2.amazonaws.com	HTTPS
EU (Paris)	eu-west-3	rds.eu-west-3.amazonaws.com	HTTPS
EU (Stockholm)	eu-north-1	rds.eu-north-1.amazonaws.com	HTTPS
Middle East (Bahrain)	me-south-1	rds.me-south-1.amazonaws.com	HTTPS
South America (Sao Paulo)	sa-east-1	rds.sa-east-1.amazonaws.com	HTTPS
AWS GovCloud (US-East)	us-gov-east-1	rds.us-gov-east-1.amazonaws.com	HTTPS
AWS GovCloud (US-West)	us-gov-west-1	rds.us-gov-west-1.amazonaws.com	HTTPS

Quickly Configuring the AWS CLI

$ aws configure
AWS Access Key ID [None]: AKIAIOSFODNN7EXAMPLE
AWS Secret Access Key [None]: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
Default region name [None]: us-west-2
Default output format [None]: json

AWS CLI can be installed in MAC using below AWS user guide : https://docs.aws.amazon.com/cli/latest/userguide/install-macos.html#install-bundle-macos

AWS CLI can be installed in Windows using below AWS user guide : https://docs.aws.amazon.com/cli/latest/userguide/install-windows.html

High Availability can be achieved by deploying your application across multiple availability zones ( two or more availability zones ) . You can also deploy multiple tiers ( web, application and database ) of your application in different availability zones for high availability. 

What is cloud computing ?
Cloud computing is offering IT infrastructure services to businesses in form of web services.
Cloud computing is on demand delivery of IT resources and applications via internet with pay as you use pricing.
 Key benefits of cloud computing :
Replace business up front capital infrastructure expenses with low variable costs
Business need not plan and procure servers or IT infrastructure weeks or months in advance. They can instantly spin up servers in minutes

Cloud computing providers Amazon AWS, Microsoft Azure and Google Cloud