Amazon Web Services (AWS) is a collection of remote computing services, also called web services, that make up a cloud computing platform by www.amazon.com. The most central and well-known of these services are Amazon EC2 and Amazon S3 Amazon Web Services offers reliable, scalable, and inexpensive cloud computing services.
The AWS components are:
- S3 is used to retrieve datasets involved in cloud architecture and is used to store the output datasets that are the result of the computations.
- SQS is leveraged for buffering requests received by the Amazon controller. It is the component used for communication between different controllers.
- SimpleDB is used to store intermediate logs and tasks performed by the user.
- EC2 is used to run a large distributed processing on the Hadoop cluster and provides automatic parallelization and scheduling.
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Isolation facilitates a way to hide the architecture and gives an efficient mechanism to leverage the services without hassle. When a message is passed between two controllers, a queue is maintained to store these messages. Controllers don't call each other directly. The communication happens between the controllers by storing their messages in a queue. This mechanism provides a uniform way to transfer messages between different application components. This way all the controllers are isolated from one another in the ecosystem.
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The Elastic Compute Cloud, also known as EC2, is an Amazon Web Service that provides scalable resources and makes computing easier. The main functions of Amazon EC2 are:
- It facilitates configurable options and allows users to configure the capacity
- It facilitates complete control of computing resources and lets users run the computing environment according to requirements
- It facilitates a fast way to run the instances and quickly book the system, thus reducing the time
- It facilitates scalability to resources and changes its environment according to requirements
- It facilitates a variety of tools to build failure resilient applications
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The instances that can be used in Amazon EC2 are:
- Standard instances provide small, large, and extra large instances that give various configuration options from a low to very high range of computing power, memory, processors, and so on
- Micro instances provide small consistent resources such as CPU, memory, and computing units, and provide resources to applications that consume a lesser amount of computing units
- High memory instances provide large memory sizes for high-end applications, and include memory caching applications as well
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The following list explains the capabilities of the virtual private cloud (VPC):
- The Amazon private cloud provides a provision to create a private networking infrastructure
- Virtual network topologies define the traditional data center approach to control and manage the files from a single location
- It provides complete control over the IP range, the creation of subnets, and the configuration of network gateways and router tables
- It provides easy to customize network configuration such as the creation of public subnets to access the Internet
- It allows for the creation of multiple security layers and provides network control lists by which you can control the access to Amazon EC2 instances
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Amazon EC2 is a web service that provides scalable computing capacity in the cloud. You can use Amazon EC2 to launch as many virtual servers as are required. With Amazon EC2, you can configure security and networking, and manage storage.
Amazon EC2 provides the following features:
- A virtual computing environment with instances
- Pre-configured templates for instances, such as Amazon Machine Images
- Amazon EC2 provides various configurations of CPU, memory, storage, and networking capacity
- Secure login information for instances using key pairs
- Storage volumes for temporary data that's deleted when you stop or terminate your instance
- Amazon EC2 provides persistent storage volumes with the Amazon Elastic Block Store
- Static IP addresses for dynamic cloud computing with Elastic IP
- Amazon EC2 provides virtual networks that are logically isolated from the rest of the AWS cloud through virtual private clouds
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An Amazon Machine Image (AMI) is a template that contains software configurations (for example, an OS, application server, and applications). An AMI can launch an instance, which is a copy of the AMI running as a virtual server in the cloud.
AWS provides several ways to access Amazon EC2, such as a web-based interface, AWS Command Line Interface (CLI), and Amazon tools for Windows Powershell. The requests are HTTP or HTTPS requests that use the HTTP verbs GET or POST and a Query parameter named Action.
One can launch different instance types from a single AMI. An instance type essentially determines the hardware of the host computer. After an instance is launched, it looks like a traditional host, and we can interact with it as we would any computer. We have complete control of our instances; we can use sudo to run commands that require root privileges.
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Approaches to leveraging services from a public cloud platform include:
- Leveraging a public cloud computing platform is easy and inexpensive as hardware, applications and network costs are covered by the cloud provider and are charged on a usage basis.
- Computing resources in a public cloud can be scaled to meet the needs of the cloud consumers.
- A public cloud leverages flexible pricing models. No resources are wasted because the cloud users pay for the consumption on an on-demand basis, without the need to invest in additional infrastructures.
- A public cloud helps businesses shift the costs from capital expenditures and IT infrastructure investment to a utility operating expense model. A public cloud helps segregate the end users from the complexity of IT operations management.
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The key concepts of SaaS are:
- Tenancy in the same environment can be shared among many customers
- The payment method in SaaS is normally modeled as pay-as-you-go, which is different from traditional licenses
- The SaaS provider is responsible for managing the computing environment
- The SaaS provider can upgrade the application or release new features seamlessly, in contrast to the traditional and costly software upgrade
The following are the examples of SaaS:
- Google Docs
- LotusLive
- Salesforce.com
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Grid computing is a type of distributed architecture that enables sharing, selection, and aggregation of geographically distributed autonomous resources dynamically at runtime depending on their availability, capability, performance, cost, and users' quality-of-service requirements.
Grid computing involves distributed computing and parallel computing, whereby a cluster of networked, loosely-coupled nodes act in concert to perform very large tasks. The goal of grid computing is to divide a single and large task among many loosely-coupled computers. Grid computing may run in a cloud computing environment. The main difference is that grid computing is comprised of many nodes working together to achieve one goal, and cloud computing is aimed at providing computing resources for various tasks.
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