Appendix
Regions and Availability Zones
Region and Availability Zone Concepts
Each region is completely independent. Each Availability Zone is isolated, but the Availability Zones in a region are connected through low-latency links. The following diagram illustrates the relationship between regions and Availability Zones.
You can list the Availability Zones that are available to your account. For more information, see Describing Your Regions and Availability Zones. When you launch an instance, you can select an Availability Zone or let us choose one for you. If you distribute your instances across multiple Availability Zones and one instance fails, you can design your application so that an instance in another Availability Zone can handle requests.
Amazon EC2 resources are either global, tied to a region, or tied to an Availability Zone. For more information, see AWS documentation for the complete article.
Amazon EC2 uses public–key cryptography to encrypt and decrypt login information. Public–key cryptography uses a public key to encrypt a piece of data, such as a password, then the recipient uses the private key to decrypt the data. The public and private keys are known as a key pair.
To log in to your instance, you must create a key pair, specify the name of the key pair when you launch the instance, and provide the private key when you connect to the instance. Linux/Unix instances have no password, and you use a key pair to log in using SSH. With Windows instances, you use a key pair to obtain the administrator password and then log in using RDP.
Creating a Key Pair
You can use Amazon EC2 to create your key pair. For more information, see Creating Your Key Pair Using Amazon EC2. Alternatively, you could use a third-party tool and then import the public key to Amazon EC2.
For more information, see Importing Your Own Key Pair to Amazon EC2.
Each key pair requires a name. Be sure to choose a name that is easy to remember. Amazon EC2 associates the public key with the name that you specify as the key name. Amazon EC2 stores the public key only, and you store the private key. Anyone who possesses your private key can decrypt your login information, so it’s important that you store your private keys in a secure place.
The keys that Amazon EC2 uses are 1024-bit SSH-2 RSA keys. You can have up to five thousand key pairs per region.
Launching and Connecting to Your Instance
When you launch an instance, you should specify the name of the key pair you plan to use to connect to the instance. If you don’t specify the name of an existing key pair when you launch an instance, you won’t be able to connect to the instance. When you connect to the instance, you must specify the private key that corresponds to the key pair you specified when you launched the instance. Amazon EC2 doesn’t keep a copy of your private key; therefore, if you lose your private key, there is no way to recover it. If you lose the private key for an instance store-backed instance, you can’t access the instance; you should terminate the instance and launch another instance using a new key pair. If you lose the private key for an EBS-backed instance, you can regain access to your instance. For more information, see Connecting to Your Instance if You Lose Your Private Key.
Detailed VPC Diagram
Figure 36
Additional info and links http://aws.amazon.com/documentation/vpc/
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Introduction.html