Dr. Dobb's Journal - February 2009 - (Page 17)

d02moore_p3cp 12/11/08 2:01 PM Page 17 depends on the network for the user, and the supporting network infrastructure offered by the provider. If users can’t get to the cloud, your application is out of luck. Second, service-level agreements are not always present, so think carefully regarding mission-critical applications. Also, security is always a concern. Additionally, note that AWS and GAE are vastly different in the development and deployment models. The cloud offerings are dramatically different; you will have to use different development styles for each. Finally, examine your support options (what happens when the cloud goes away?). Amazon Web Services Amazon Web Services (AWS) emerged directly from the challenges in running amazon.com and incorporates an Amazon perspective. AWS offers the cloud at two distinct levels—raw computing resources and readyto-go appliances. The former offers traditional computer resources, such as processors, memory, file system/database, and messaging. The ready-to-go appliances build useful applications and/or services on top of the raw resources. Amazon supplies and manages the raw computing resources. Amazon partners typically provide the ready-to-go appliances. AWS charges a la carte for usage of the raw resources—processor, memory, network traffic, and storage. Partnering appliances are free to attach a surcharge to the resources that implement their offerings. Amazon is actually the enabler. It depends on partners or you to create useful applications. Additionally, third-party solutions have emerged to manage AWS resources directly. At this writing, AWS consists of five primary services: • Elastic Compute Cloud (EC2) offers virtual machines (VMs) containing processors, memory, and storage. All of the VMs are Linux variants. They just started to offer proprietary operating systems such as Windows Server and Oracle Enterprise LInux. A cloud application can dynamically allocate and deallocate the VMs. EC2 offers a variety of VM sizes from small 32-bit processors to 64-bit multicore processors, all with corresponding memory and storage. Currently, EC2 is in beta and does not offer a service-level agreement (SLA). EC2 machines may associate themselves with AWS-allocated name elastic IPs. You can protect each VM with a configurable firewall called security groups. A security group enables protection via IP source, to/from IP port, IP protocol, user, or group. You may maintain different security groups for different VMs. • Simple Storage Service (S3) offers large storage. The storage is simple and direct. You declare buckets and place data objects into the bucket. Each bucket and object maintains a security profile that controls access. Several third-party tools use the API to provide a filesystem-like view into the buckets. Each bucket can also tie to a URL to provide direct access. S3 offers an SLA (www.amazon.com/ gp/browse.html?node=379654011). • Simple Queue Service (SQS) offers a highly reliable message queue. SQS guarantees delivery of messages and stores messages for later transmission if required. SQS interconnects all of AWS resources. Applications publish and subscribe to a specified queue. • SimpleDB provides a query interface to structured textual data. The query language and data formatting is, well, simple. Your primary data can associate with up to 256 attributes or metadata. Your application can then use basic Boolean operations to query the information. This is currently in limited beta. • Cloud Front provides efficient access to distributed content using Amazon’s array of servers throughout the world. It integrates with S3, which holds the original content that is then distributed appropriately to edge servers. It provides high data transfer rates and low latency. As with the other services, price is based on usage. To access any of these services, you must get an account and activate the services you Figure 1: JetS3t presentation of S3. Figure 2: JungleDisk presentation of S3. Figure 3: ElasticFox EC2 View. February 2009 l www.ddj.com l Dr. Dobb’s Journal 17 http://www.amazon.com/gp/browse.html?node=379654011 http://www.amazon.com/gp/browse.html?node=379654011 http://www.amazon.com http://www.amazon.com http://www.ddj.com

Table of Contents Feed for the Digital Edition of Dr. Dobb's Journal - February 2009

Dr. Dobb's Journal - February 2009 Contents Friday Night Fish Fry Alia Vox Developer Diaries Conversations Computing in the Clouds Software Development in the Cloud Videos and Oracle Forms 10g Parallel LINQ Decoupling C Header Files Effective Concurrency Disciplined Agility Swaine’s Flames

Dr. Dobb's Journal - February 2009

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