ArcGIS Server on Amazon EC2 - Introduction to Amazon Web Services terminology

Before you begin working with ArcGIS Server on Amazon Web Services, there are some new terms and concepts that are helpful to learn.

ArcGIS Server Cloud Builder on Amazon Web Services

ArcGIS Server Cloud Builder on Amazon Web Services is a free downloadable app that helps you create an ArcGIS Server site in Amazon EC2. The app runs on your desktop and requires your Amazon Access Key and Secret Access Key to log in. Once you've logged in to the app, you choose the operating system you want to use for the site and how many machines it can contain, along with some other parameters. You then click a button and the site is created for you. You can also edit existing sites that you've created with the app.

AWS Management Console

The AWS Management Console is Amazon's web-based interface for managing your Amazon Elastic Compute Cloud (EC2) instances. Although you can, and should, perform most of your site administration tasks in Cloud Builder, the AWS Management Console allows you to wield finer control over your ArcGIS site architecture by adding storage volumes, adjusting security groups, and so on.

The AWS Management Console requires you to log in with an account that you've set up with Amazon for the purpose of using its cloud. The AWS Management Console allows you to view your account information and accumulated charges.

EC2 instance

An EC2 instance is a virtual machine that you create in EC2. You create the instance using an AMI that is preconfigured with an operating system and ArcGIS software already installed. When you create a site with ArcGIS Server Cloud Builder on Amazon Web Services, EC2 instances are created behind the scenes.

The following AMIs are available. Each AMI includes a database managment system (DBMS) so that an ArcSDE geodatabase can be created with versioning and other benefits:

ArcGIS for Server (Windows) with Microsoft SQL Server Express—Ideal for workgroup geodatabases (but can be used for enterprise geodatabases). Runs on Windows Server 2008 R2.
ArcGIS for Server (Windows) with Microsoft SQL Server—Ideal for enterprise geodatabases. Runs on Windows Server 2008 R2.
ArcGIS for Server (Linux) with PostgreSQL—Runs on Ubuntu Linux.

You can optionally create the geodatabase on a separate instance and attach it to your ArcGIS Server instance.

Once you create the instance, you can log into it. For example, you can access a Windows instance using a Windows Remote Desktop Connection. If you've worked with ArcGIS before, this is where things start to look familiar. For example, once logged in to an instance, you can use ArcMap to create and manage services.

You can stop and start EC2 instances in much the same way you can shut down and start up a computer. Instances can also be terminated when they are no longer needed. Once you terminate an instance, all information about it is lost. For this reason, it's recommended that you store your data on Amazon Elastic Block Store (EBS) volumes attached to your instance and optionally back up your data using Amazon Simple Storage Service (S3).

After creating an instance, you'll add your data, services, and other programs. Once you've configured your instance exactly the way you want, you can use ArcGIS Server Cloud Builder on Amazon Web Services to create a site template reflecting your machine's current state. You can use this template to launch a production site whose instances are preconfigured with your data and services.

EBS volume

Amazon Elastic Block Store (EBS) volumes are virtual disk drives that you can attach to your EC2 instance to add more storage. The ArcGIS Server Windows AMIs create an EBS volume and attach it to the instance as the D: drive. The ArcGIS Server Ubutu AMI also creates an EBS volume named /gisdata that is mounted to the instance. The size of this volume is configurable in Cloud Builder, or it is 10 GB if you launch your site from the AWS Management Console.

You can choose to place your data on these preattached volumes, replace them with volumes of a different size, or attach more volumes.

If you create your own EBS volume, you must do the work of formatting the drive and attaching it (for example, you can configure it as drive E: on Windows). You can configure the drive to contain as much or as little space as you need.

EBS volumes are an excellent way to manage your data in the cloud independently from your software. For example, you can easily detach an EBS volume from one instance and attach it to another. When you terminate an instance, any previously attached EBS volumes are left behind, allowing you to attach them to other instances if desired.

You can create snapshots of your EBS volumes, which allow you to quickly generate identical volumes. Snapshots are useful if you need to share data across Amazon availability zones, or if you want to make the same data available to several Amazon accounts. Finally, snapshots provide a means of data backup. If a volume fails for some reason, you can deploy a new volume from the original snapshot without much loss.

Elastic Load Balancer

Amazon Elastic Load Balancers (ELBs) are a way to distribute work across multiple EC2 instances. All requests to your server go through the load balancer, which then evenly distributes the requests to the available EC2 instances. You can add or remove participating EC2 instances from the load balancer any time. When you build a site with ArcGIS Server Cloud Builder on Amazon Web Services, an ELB is configured for you and your GIS server instances are placed beneath it.

Regions and Availability Zones

Amazon EC2 consists of multiple data centers around the world that are designed to address enterprise architecture challenges.

Amazon Regions represent data center facilities in dispersed geographic locations such as the United States, Europe, and Asia.
Amazon Availability Zones are distinct locations within a region that are engineered to be isolated from failures in other Availability Zones. Configuring your application in multiple zones provides an extra layer of availability in case one of the zones should fail.

S3

Amazon Simple Storage Service (S3) is an Amazon service designed specifically for data storage in the cloud. This storage option has the lowest potential for data failure or loss. You can use S3 as a place for data backup or as a middle ground for data transfer between your on-premises deployment and your EBS volumes. Also, any snapshots you create of your EBS volumes are stored on S3.

12/10/2013