What is EC2?
Amazon Elastic Compute Cloud (Amazon EC2) is a web service that provides resizable compute capacity in the cloud. It is designed to make web-scale computing easier for developers.
What can developers now do that they could not before with EC2?
Until now, small developers did not have the capital to acquire massive compute resources and ensure they had the capacity they needed to handle unexpected spikes in load. Amazon EC2 enables any developer to leverage Amazon’s own benefits of massive scale with no up-front investment or performance compromises. Developers are now free to innovate knowing that no matter how successful their businesses become, it will be inexpensive and simple to ensure they have the compute capacity they need to meet their business requirements.
The “Elastic” nature of the service allows developers to instantly scale to meet spikes in traffic or demand. When computing requirements unexpectedly change (up or down), Amazon EC2 can instantly respond, meaning that developers have the ability to control how many resources are in use at any given point in time. In contrast, traditional hosting services generally provide a fixed number of resources for a fixed amount of time, meaning that users have a limited ability to easily respond when their usage is rapidly changing, unpredictable, or is known to experience large peaks at various intervals.
What is the difference between using the local instance store and Amazon Elastic Block storage (Amazon EBS) for the root device?
EBS on the EC2 instance allows for data to be persisted even when the instance is shut down and restarted. Local store does not have this capability.
How can you load various EC2 systems quickly, without the need to configure each one step by step
You can use an AMI to start from, which will contain prepackaged information about what should be in that image. AMI’s can be taken from an instance you’ve built or from globally available AMIs on community and marketplace
How many instances can I run in Amazon EC2?
20 on-demand, 20 Reserved. And spot has dynamic restrictions per region.
Any limitations in sending email from EC2 instances?
Yes, there are default limits but you can apply for sending larger amounts of email.
Does Amazon EC2 use ECC memory
yes
What’s the base pricing for EC2?
Per instance-hour
How are partial instance-hours billed?
As full instance-hours
What is a billable instance hour?
any time an instance is in a “running” state.
Does a billable instance hour start when an instance has reached a running state?
No. It starts as soon as the transition to a running state begins
How many Elastic IP addresses per region are you limited to, if any?
5, but can apply for more
What use cases justify using a private IP address rather than an elastic IP? (3)
Compute clusters, web crawling, and backend services.
How long does it take to remap an Elastic IP address
several minutes
