We can use it to run an app, virtual desktop, 3rd party software, computing. Instance is an OS image or AIM. AWS Marketplace offers many images. Instance Type is where you select what services you want to use.
Auto Scaling Group = AWS increase or decrease instances automatically based on your program. Elastic Block Storage (EBS) is use in EC2 for file systems. S3 for file storage. Security Group is a little firewall for instances.
Use without a key-pair if you want to log-in by using username/password.
charge by hour based on instance type, AMI Type. See https://aws.amazon.com/ec2/pricing/ Only pay for hour when it is on.
EBS is charged separately.
Simple Storage Service (S3)
The place to store files. Maximum file size is 5 TB! Structure of S3 is a bucket. S3 bucket URL can be accessed after setting permissions. We can host a static website using S3. We can auto replicate files on other regions using bucket.
There are many other Cloud solutions. For examples,
Microsoft Azure – started around 2010. Model is the same as AWS. Pricing is hard to compare with AWS. If you need Windows virtual machines, it is good to choose Azure. .NET App is also good to run. Not global reach like AWS.
IBM Bluemix – very new lunch in 2014. Cloud Foundry open source. If you want an independent provider, this one is a good fit.
Heroku – started in 2007. Easy and quick to get start.