Glossary of Terms

EC2 stands for Amazon's Elastic Compute Cloud. Using EC2 you can launch instances (specific packages of dedicated compute resources) that look and feel just like traditional remote servers. Resources are delivered in a matter of seconds, not days or weeks as with traditional providers and you can now request 10, 100, 1000+ servers based on your web applications needs at any given time. EC2 changes the way that computing resources are delivered to the consumer. You are no longer limited by server capacity or long term service contracts. EC2 delivers a utility computing model where you pay as you go and only pay for what you use. It also provides full control of these resources where you can launch and terminate new servers at will.

For more information about EC2, including instance sizes, pricing, and to sign up for EC2 visit, http://aws.amazon.com/ec2.

In addition to selling books and variety of other consumer products, Amazon also offers a variety of web services that help web developers build next generation web platforms.

RightScale offers a web interface designed that makes it easier to use the following AWS Services:

• EC2 - Elastic Compute Cloud.
• S3 - Simple Storage Service.
• SQS - Simple Queue Service.

An instance is the AWS version of a server. They come in three sizes small, large, and extra-large (for more information and pricing - click here) and are designed to provide predictable and dedicated computing power on demand. Amazon charges you directly based on instance-per-hour usage.

A deployment is a clustered architecture that represents all the instances (servers) in your application and associates them with each other. As a result you're able to specify global parameters that all of the instances inherit, which makes it really easy to add additional components without the need for extra configuration. The RightScale Dashboard makes it easy for you to start and stop entire deployments on demand, clone deployment clusters to create identical staging or QA environments, and define and link variables that apply to scripts distributed across all of your servers. Creating a deployment is as easy as selecting and adding the servers you want, defining your variables, and clicking Launch.

A compute unit is measurement tool used to compare and contrast different virtual servers (instances). One EC2 Compute Unit provides the equivalent CPU capacity of a 1.0-1.2 GHz 2007 Opteron or 2007 Xeon processor. This is also the equivalent to an early-2006 1.7 GHz Xeon processor.

An AMI is a packaged environment that contains a configured Linux operating system. We recommend using our own custom RightImages. They contain a lightweight server installation with all of the tools necessary to use EC2 and RightScale.  All of our scripts are provided to our customers for further customization to meet your needs

When you launch an image through AWS, you will specify a particular SSH Key to associate with that image.  This allows you to gain access to your machines without using passwords.  This is the recommended (and more secure) way to access your instances.  RightScale uses this key to communicate and monitor your instances.  Do not change it.

A security group is Amazon's version of a firewall that includes some addtional features.  It allows you to specify certain security settings on an instance specific basis. You have the ability to filter traffic based on IP's (a specific address or a subnet), packet types (TCP, UDP or ICMP), and ports (or a range of ports). You can also grant access to an entire security group. This allows your trusted machines to access each other without having to open ports to the public.

For even more security, Amazon provides the option of completely removing public access to an instance. This will ensure that you are safe from any outsiders gaining access to your machine and even prevents even Denial and Service attacks.

An Array is a single server type used for horizontal scaling. It may be a single worker slave task plugged into our RightGrid system to scale based on the number of jobs in a queue. Or it may be your Deployment's application server that you want to scale dynamically based on the load or even schedule to scale based on known traffic patterns. Defining an array is simple. Select the type of server you would like to scale and then just define what deployment you're scaling and how you would like RightScale to automate the process for you.

Amazon Simple Storage Service (S3) is the distributed storage component of the AWS platform.  It can read, write, and delete objects representing data ranging from 1 byte to 5 gigabytes. You can use S3 to store, replicate, and persist an unlimited amount of objects in the cloud. However, you should not think of S3 as a local disk and attempt to run your database from S3.

S3 simply stores “objects” or files, in “buckets” (folders). Since there are no directories in S3, each bucket is given a unique identifier. You can also have multiple buckets under one account. Many customers serve static files such as images or video directly from S3 instead of having them stored on a local disk. This gives them virtually infinite storage capacity for their files without purchasing any hardware.

RightScale provides an S3 Browser and an EC2 Image Locator to help you scan and monitor your buckets.

For more information visit: http://aws.amazon.com/s3

A bucket is an S3 storage area assigned using a unique key.  You can use buckets to make data public or private, and authenticate user access to your data. Currently, you can also requisition buckets in North America and Europe.  Data in these buckets are stored in those geographic locations, but can be accessed from anywhere based on the authentication credentials that you specify.

Objects are stored inside buckets.  They are the fundamental entities in S3.

A key uniquely identifies the object within a bucket.  Together, a key and a bucket are used to identify an object inside S3.

A deployment is a heterogeneous cluster of servers that represents your web application. It may include web front ends, application servers, worker slave machines, and your database servers. RightScale provides the ability to cluster a deployment, define inputs across all the servers within that deployment, and even clone it to create an identical server cluster.

An array is a single server type linked to a deployment that is used for horizontal scaling. For example, if there is an instance that you would like to launch multiple copies of, such as an application server or worker slave task, you should define it as an array. Setting the elasticity parameters of that array allows RightScale to make decisions when to grow or shrink the size of that array. Parameters may include load-based thresholds, scheduled scaling, or number of jobs in a queue. RightScale uses a unique voting system to take the status of all of your related instances into consideration before making the decision to launch or terminate new servers. This safety feature ensures that no one single instance is responsible for executing a decision that may not be reflect the total load across your entire deployment.

A server template defines the composition and configuration of your instance. When an instance is launched from a server template, it uses a base OS image and a series of scripts to install and configure your server as it boots. This allows you to work at a much more granule level than simply from an AMI alone.

A RightScript is any script that you define within RightScale. It may be a shell script, a perl script, a ruby script, a python script, etc. These scripts can be defined as boot scripts for a server template, which run at boot time, or as operational scripts, where can be run from the Actions tab in the RightScale Dashboard on an operational instance. You can also connect RightScripts to escalation actions and have them run when a particular alert condition is met.