Cloud Computing Info

CloudFront

Amazon CloudFront is Amazon’s Content Delivery Network (CDN). A CDN puts very large servers with high throughput at the edge of the network. That means that a CDN provider put cached data in multiple locations through out the network (internet). Requests for data are routed to a local server cache instead of the main server at a host. This improves performance, customer experience and possibly even costs (via lower bandwidth requirements).

An example would be a company that serves many pages to many users. Rather than have all of the pages stored in a central location and be accessed by many people all at once, the pages are distributed throughout the network and sit on many different servers.

Amazon Flexible Payments

Amazon Flexible Payments Service (FPS) is a set of web services that allow businesses or developers to bill users using the Amazon payment infrastructure (like a PayPal or Google Checkout). As a seller or a buyer, you can set limits on usage either globally or for specific senders and/or receivers. A gatekeeper component enforces the rules.

As a sender you can limit the number of transactions, transaction dates, dollar amounts, recipients and daily, weekly or monthly spending limits. Recipients can specify all of those and can specify allowable payment methods (credit card, bank transfer and amazon payments) and who pays the transaction fee.

One of the goals of FPS is to make micropayments effective and financially cost effective.

Simple Queue Service (SQS)

SQS is Amazon’s message queuing service. It works much like IBM’s MQ Series, JMS or Oracle AQ. Pop in a message and one or more recipients can pop it out. SQS is completely open so any internet connected computer can call a web service and add or remove a message.

Because SQS is API based, you can write an interface to it in the language of your choice. There are several free Java, Ruby and PHP interfaces available (that I know of) with more coming.

Elastic Compute Cloud (EC2)

Elastic Block Storage (EBS)

For most of its life in beta, EC2 offered only two kinds of storage, AMI based transient storage and S3. The transient storage was mounted as a filesystem and S3 was used for backup. To save data during downtime for instances, data had to first be saved off to S3 and the instance brought down. When the instance was brought back up, data was restored from S3. It was a painful process.

Enter EBS, the Elastic Block Store.

Simple Storage Service (S3)

Cost

Storage is cheaper in the US than in Europe. If you are based in Europe, you may want to decide which is more important when getting or adding data: price or latency.

Table 3: S3 Storage Costs

Table 4: S3 Data Transfer Costs

Table 5: S3 Request Costs

These prices are accurate as of the time of writing them.

Simple Storage Service (S3)

Security

Write and delete access to buckets and objects is controlled via Access Control Lists (ACL). You can assign read permissions to any object to specific users. You can also make an object public to grant access to anyone.

Transfer into and out of S3 can utilize SSH which will encrypt data. This prevents any “over the wire” interception of your data. Data at rest is not encrypted and Amazon recommends that users encrypt any sensitive data with their encryption tool of choice.

Simple Storage Service (S3)

The AWS S3 service is an API driven storage service. The API provides get, put and delete. Data is stored using a bucket concept that is not unlike directories and sub-directories. A bucket can hold one or more buckets and one or more objects (i.e. files). You can nest buckets as many levels deep as required by your application or other needs. Objects can be up to 5GB per and you can store an unlimited number of objects.

At the top level is a global bucket. All S3 accounts share the global bucket.

Sizing and Costs

EC2, like the other services in AWS are pay as you go, pay for what you use, services. As I mentioned above, you basically pay for the power you use which is a CPU per hour charge, bandwidth and storage. Linux and Windows guests have a different pricing menu. I am listing the prices current as of Dec 2008. I recommend you always check at aws.amazon.com to verify current pricing before making a commitment.

Instead of buying or leasing a specific type of hardware (that you would then be responsible for upgrading over time), AWS computing power is based on an EC2 compute unit.

Cloud Computing Info

Elastic Compute Cloud (EC2)

Transient Storage

The storage that comes with an AMI is called Transient Storage. That means that when the instance is stopped, the storage goes away. Any data or files saved when the instance was running is lost. This is by design.

To persist your data between sessions, you have two options. During most of the beta period, the Simple Storage Service (S3) was the only internal method of persisting data. S3 cannot be mounted as file system so it served as a backup service only.

Shortly before the beta period ended, Amazon added the Elastic Block Store (EBS).

Cloud Computing Info

Elastic Compute Cloud (EC2)

Security and Security Groups

Security is one of the most important, if not the most important, aspects of any important application. If you are thinking about running any kind of a mission critical application in the cloud, security should be a large part of your research.

AWS has been independently certified as Sarbanes-Oxley compliant and has passed a SAS70 audit. Amazon’s physical data center security follows established norms and is routinely audited.

On the software side, Amazon maintains a separation between host operating systems (those that Amazon are responsible for) and guest operating systems (the AMIs).

Cloud Computing Info

Elastic Compute Cloud (EC2)

Elastic IPs

Elastic IPs are a very neat feature of EC2. An Elastic IP is a configurable IP address assigned to your account. Unlike the rest of the features in AWS, you pay for any elastic IPs that you have allocated but not used. Amazon doesn’t want customers hoarding, and thus wasting, this resource. If you set aside the IP and use it, it’s free. If you set it aside and just keep it hanging around unused, you’ll pay a small monthly fee.

These IP addresses are connected to your account so you can assign them to any instance you might be running.

Cloud Computing Info

Elastic Compute Cloud (EC2)

EC2 is the computing part of the Amazon services. EC2 provides the CPU, memory, operating system and transient storage. EC2 is the equivalent of a barebones PC. You get to pick the amount of RAM you need (from a predefined list of configurations), the amount of transient storage you need (also from a list) and the number of CPUs you need (from a series of compute options). For the operating system, you can choose from various flavors of Linux, Solaris or Microsoft Windows Server.

If you can use a web browser and understand basic computer technology, you can use EC2.