Amazon EC2 Concepts
Internal
Security Concepts
AMI (Amazon Machine Image)
An Amazon machine image is a template that contains a software configuration (operating system, application server, application).
Instance
From an AMI, you can launch an instance, which is a copy of the AMI running as a virtual server on a host computer in Amazon's data center. You can launch multiple instances from an AMI. An instance can be accessed using its public DNS name or public IP address. The DNS name follows the following pattern: ec2-<public_ip>.<region_code>.compute.amazonaws.com. An instance keeps running until it is explicitly stopped or until they fail. You can start from an existing AMI, log onto the instance, customize it with additional settings and software, and then save this customized image as a new AMI.
Instance Type
- http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.htm
- Instance Type Description http://aws.amazon.com/ec2/instance-types/
- How many instances can I run? http://aws.amazon.com/ec2/faqs/#How_many_instances_can_I_run_in_Amazon_EC2
When you launch an instance, you select the instance type, which determines the hardware capabilities: memory, CPU and storage.
Instance Metadata and User Data
Subnet
A subnet is a range of IP addresses in the Virtual Private Cloud (VPC) that can be used to isolate different EC2 resources from each other or from the Internet. Each subnet resides in one Availability Zone. Subnets enable you to group instances based on security and operational needs. To enable instances in a subnet to reach the Internet and AWS services, you must add an Internet gateway to the VPC and a route table with a route to the Internet to the subnet.
Example:
subnet-53993c24: 172.31.16.0/20