Because of our broad knowledge in building web applications, AIS decided to develop a prototype that highlights the features and capabilities of open standards for geospatial processing and data sharing through web applications.

We chose the Visible Infrared Imaging Radiometer Suite (VIIRS) as our data source for the demonstration. VIIRS collects visible and infrared imagery and radiometric data for civil and military Earth monitoring. (The Day/Night Band (DNB) datasets available from NOAA’s Comprehensive Large Array-Data Stewardship System are not quite in the format we need for our application, since they are sensor data records stored within an HDF5 container.)

Andrew Middleton

Amazon Web Services (AWS) provides an extremely flexible set of services for hosting web applications in the cloud with a web-based console for selecting options to quickly provision a set of IT resources. This post will explore the various aspects of hosting a custom .NET web application in AWS, focusing on high-availability options and disaster recovery scenarios and how to do so under cost constraints.

When building a solution in AWS you have to understand the difference between affinity and availability, and the terminology that Amazon uses. We will define affinity as the physical location of resources within a data center and availability as the isolation of resources for disaster recovery scenarios.

The AIS solution I’ll reference throughout this post uses a Virtual Private Cloud (VPC) to enable our engineers to develop a multi-tiered application within a private sub-netted network split across two availability zones. The VPC as defined by Amazon allows for “… you to create a virtual network topology—including subnets and route tables—for your Amazon Elastic Compute Cloud (Amazon EC2) resources.” The use of a VPC ensures you have high affinity for your EC2 resources. Availability zones refer to the geographically separated data centers Amazon uses for hosting EC2 resources. Therefore, your disaster recovery architecture must account for placement of EC2 resources in different Availability Zones.

High Availability vs. Disaster Recovery in AWS

To muddy the terminology waters further, we have the concept of high availability, where the effects of hardware or software failure are essentially masked and downtime for end users reduced, such as in Microsoft’s SQL Server. Our solution had to address the issue of high availability and allow for a swift recovery in the event of a disaster or failure of EC2 resources in one availability zone. A high-level picture of what we needed to achieve is shown below.

David Zientara

Here at AIS, we’ve found Windows Azure Blob Storage to be an inexpensive, fast hosting solution for non-text or server-side loaded resources. But what if we want to use client-side JavaScript to load HTML fragments or JSON data directly from blobs? Under normal circumstances this is prevented by JavaScript’s Same Origin Policy; that is, you can’t load HTML fragments or JSON from another domain, subdomain, port or protocol.

One commonly used solution to this restriction is JSONP, but this is not available with Azure Blob Storage. Another modern option is Cross-Origin Resource Sharing (CORS), but it is also unavailable on Azure Blob Storage and not supported in some legacy browsers.

We could consider a server-side solution, such as employing an Azure Web Role to read text-based content from blob storage and serve it up from the original server. But this approach can be both wasteful and performance inhibiting.

Chris Hettinger

Part 1: Plan Overview

In this first video, we take a high-level look at Amazon Web Services (AWS) terms, server implementation, and a simple backup plan.

Kevin Griffie

As a Microsoft partner with several gold competencies and cloud memberships, we are entitled to an extensive suite of internal use licenses for many of Microsoft’s on-premise and cloud products. During our recent rollout of Office 365, the elegance of Microsoft’s long-term vision of federating authentication (which has been evolving since the release of Active Directory Federation Services (ADFS) 1.0 in 2005) really stood out.

Once an ADFS 2.0 infrastructure is in place, federating authentication with our hosted Office 365 environment was relatively easy. Our users now have access to hosted versions of Lync, Exchange and SharePoint using their familiar domain credentials. Up next for us is migrating our current Dynamics CRM Online deployment into the Microsoft online services portal environment where our Office 365 environment is managed. Once this change is complete, CRM will leverage the same ADFS-based federated authentication platform. Read More…

Applied Information Sciences Blog

Category Archives: Amazon Web Services

High Availability vs. Disaster Recovery in AWS

Part 1: Plan Overview