Understanding Amazon Web Components And Services

Published Date: 02 Nov 2017

Amazon launched its Web Services business back in 2006 and is on the forefront of an industry-wide overall Cloud initiative.  Amazon Web Services is the umbrella of services provided by Amazon, under which Amazon EC2 and Amazon S3 make up the most popular services. 

The Amazon Elastic Compute Cloud or EC2, allows users to pay for what they use.  Server instances are "spun up" on demand and are "spun down" when usage ceases.  These instances are simply virtual machines based on top of the Xen VM that are managed by Amazon’s internal resource management facility. The VM’s are better known as Elastic Compute Units (ECU), which are pre-packaged and can be "ordered" and simply pick and choose what you want and pay for it after you are done.  Pricing is based on the type of ECU and amount of data transferred or the time used. 

4.1 Understanding Amazon Web Components and Services

Cloud computing adopts scalable computing resources provided as a service from outside the environment on a pay-per-use basis. One can access any of the resources that live in the "cloud" at any time and from anywhere across the Internet. User doesn’t have to care about how things are being maintained behind the scenes in the cloud. Cloud computing derives from the common depiction in technology architecture diagrams of the Internet, or IP availability, illustrated as a cloud. Cloud computing has also been called utility computing or grid computing. Cloud computing is a paradigm shift in how we architect and deliver scalable applications. In the past, successful companies spent precious time and resources in building infrastructures that in turn provided them a competitive advantage. In most cases, this approach: i) left large tracts of unused computing capacity that took up space in big data centers, ii) required someone to babysit the servers and iii) had associated energy costs.

The unused computing power wasted away, with no way to push it out to other companies or users who might be willing to pay for additional compute cycles. With cloud computing, excess computing capacity can be put to use and be profitably sold to consumers.

4.1.1 Amazon Web Services

Amazon Web Services are a set of services that provide programmatic access to Amazon’s ready-to-use computing infrastructure. The robust computing platform that was built and refined by Amazon is now available to anyone who has access to the Internet. Amazon provides several Web services, building-blocks that fulfill some of the core needs of most systems: storage, computing, messaging and datasets. Amazon Web Services can help you to architect scalable systems by providing:

Reliability

The services run within Amazon’s battle-tested, highly available data centers that run Amazon’s own business.

Security

Basic security and authentication mechanisms are available out of the box and user can enhance them as needed by layering his / her application-specific security on top of the services.

Cost benefits

No fixed costs or maintenance costs.

Ease of development

Simple APIs lets us harness the full power of this virtual infrastructure and libraries, available in most widely used programming languages.

Elasticity

Scale the computing resources up or down based on demand.

Cohesiveness

The four core building-blocks using which services (storage, computing, messaging and datasets) are designed from the ground work together extremely well and provide a complete solution across a wide variety of application domains.

Community

Tap into the vibrant and dynamic user community that's driving the widespread adoption of these Web services and is creating unique applications built on this infrastructure.

There are two levels of support available for users of Amazon Web Services: i) Free forum-based support from the Amazon staff who monitor the Amazon forums and ii) Paid support packages that provide one-on-one and phone support and are a more discrete way to request help.

Amazon publishes the health status of all its Web services in a publicly accessible dashboard that is updated with any issues about the services. During any service outage, the Amazon Web Services team posts updates to every 15-30 minutes while they're working on the issue and until it is fixed.

Amazon provides standards-based SOAP and REST interfaces for interacting with each of the services. Developer libraries either from Amazon or third parties are available in multiple languages, including Ruby, Python, Java, Erlang and PHP, for communicating with these services. Command-line tools are also available for managing the computing resources on EC2.

Storage with Amazon S3

Amazon Simple Storage Service (S3) provides a Web services interface for the storage and retrieval of data. The data can be of any kind and can be stored and accessed from anywhere across the Internet. User can store an unlimited number of objects in S3, the size of each stored object can range from 1 byte to 5 GB. The data is stored securely using the same data storage infrastructure Amazon uses to power its worldwide network of e-commerce Web sites. Access restrictions can be specified for each object that is stored in S3 and the objects can be accessed with simple HTTP requests.

S3 completely frees us from worries about storage space, access to data, or securing the data. Amazon ensures high availability of the files, so they are available whenever we need them. The service-level agreement provided by Amazon for S3 commits to a 99.9% uptime, measured monthly.

Elastic computing with Amazon EC2

Amazon EC2 is a Web service that lets us to use virtual machines within minutes and easily scale the capacity up or down based on demand. These instances are based on Linux and can run any application or software. The EC2 environment itself is built on top of the open source Xen hypervisor. Amazon lets us to create Amazon machine images (AMIs) that act as the templates for the instances. Access to the instances can be controlled by specifying the permissions. Recently, Open Solaris support was announced by Amazon in a partnership with Sun Microsystems, but the vast majority of the free and commercially available pre-built images for EC2 are based on Linux.

Amazon EC2 provides true Web-scale computing, which makes it easy to scale computing resources up and down. Amazon provides five types of servers. The servers range from commodity single-core x86 servers to eight-core x86_64 servers.

Reliable messaging with Amazon Simple Queue Service

Amazon Simple Queue Service (SQS) provides access to the reliable messaging infrastructure used by Amazon. User can send and retrieve messages from anywhere using simple REST-based HTTP requests. The messages are stored by Amazon across multiple servers and data centers to provide the redundancy and reliability needed from a messaging system. Each message can contain up to 8KB of text data.

Each queue can have a configurable visibility timeout, which is used to control access to the queue by multiple readers. Once an application reads a message from the queue, the message will not be visible to any other readers until the timeout period expires. The message will reappear in the queue after the timeout period has expired and then it can be handled by another reader process.

SQS integrates very well with the other Amazon Web Services. It provides a great way to build a decoupled system where your EC2 instances can communicate with each other by sending messages to SQS and coordinate the workflow. One can also use the queues for building a self-healing, auto-scaling EC2-based infrastructure for their application.

4.1.2 Dataset processing with Amazon SimpleDB

Amazon SimpleDB (SDB) is a Web service for storing, processing and querying structured datasets. It is not a relational database in the traditional sense, but it is a highly available schema, with a less-structured data store in the cloud. SDB is simple to use and provides most of the functions of a relational database. The maintenance is much simpler than a typical database because there is nothing to set up or configure. Amazon takes care of all the administrative tasks. The data is automatically indexed by Amazon and is available to us anytime from anywhere. A key advantage of not being constrained to schemas is the ability to insert data on the fly and add new columns or keys dynamically.

4.2 Elastic Compute Cloud (EC2)

Amazon Elastic Compute Cloud (EC2) is a central part of Amazon.com's cloud computing platform, Amazon Web Services (AWS). EC2 allows users to rent virtual computers on which to run their own computer applications. EC2 allows scalable deployment of applications by providing a Web service, user can use an Amazon Machine Image to create a virtual machine, containing any software desired. A user can create, launch and terminate server instances as needed, paying by the hour for active servers, hence the term "elastic". EC2 provides users with control over the geographical location of instances that allows for latency optimization and high levels of redundancy.

Amazon EC2 is in full production since it dropped the beta label. Amazon announced the following features: i) a service level agreement for EC2, ii) Microsoft Windows in beta form on EC2, iii) Microsoft SQL Server in beta form on EC2, iv) plans for an AWS management console and v) plans for load balancing, auto-scaling and cloud monitoring services.

Amazon Elastic Compute Cloud (Amazon EC2) is a web service that provides resizable computing capacity that is used to build and host software systems.

The main components that EC2 provides are listed and briefed below:

i) Amazon Machine Images and Instances

An Amazon Machine Image (AMI) is a template that contains a software configuration (e.g., operating system, application server and applications). From an AMI, user can launch instances, which are running copies of the AMI. Also he/she launch multiple instances of an AMI, as shown in the figure 1.

ec2-1.png

Fig: 1 Amazon Machine Images and Instances

Instances keep running until user stops or terminates them, or until they fail. If an instance fails, it can be launched from the AMI. One can use a single AMI or multiple AMIs depending on needs. From a single AMI, different types of instances can be launched. An instance type is essentially a hardware archetype.

Amazon publishes many AMIs that contain common software configurations for public use. In addition, members of the AWS developer community have published their own custom AMIs.

Storage

When using EC2, data have to be stored. The two most commonly used storage types are: i) Amazon Simple Storage Service (Amazon S3) and ii) Amazon Elastic Block Store (Amazon EBS) volumes.

Amazon S3

Amazon S3 is storage for the Internet. It provides a simple web service interface that enables you to store and retrieve any amount of data from anywhere on the web. Amazon EBS provides your instances with persistent, block-level storage. Amazon EBS volumes are essentially hard disks that you can attach to a running instance. Volumes are especially suited for applications that require a database, a file system, or access to raw block-level storage. One can attach multiple volumes to an instance. To keep a back-up copy, user can create a snapshot of the volume. User can also detach a volume from an instance and attach it to a different one.

Databases

The application running on EC2 might need a database. Following are two common ways to implement a database for your application: i) Use Amazon Relational Database Service (Amazon RDS), which enables you to easily get a managed relational database in the cloud and ii) Launch an instance of a database AMI and use that EC2 instance as the database.

Amazon RDS offers the advantage of handling the database management tasks, such as patching the software, backing up and storing the backups, etc.

Amazon CloudWatch

Amazon CloudWatch is a Web service that provides real-time monitoring to Amazon's EC2 customers on their resource utilization such as CPU, disk and network. Cloudwatch does not provide any memory, disk space, or load average metrics. The data is aggregated and provided through AWS management console. It can also be accessed through command line tools and Web API's, if the customer desires to monitor their EC2 resources through their enterprise monitoring software. The metrics collected by Amazon CloudWatch enables Auto Scaling feature to dynamically add or remove EC2 instances. The customers are charged by the number of monitoring instances.

4.3 Amazon Storage Systems

Amazon Simple Store Service (S3) is a service from Amazon that allows you to store files into reliable remote storage for a very competitive price. S3 is used by companies to store photos and videos of their customers, back up their own data and more. S3 provides API for both SOAP and REST. Amazon Simple Storage Service, also known as Amazon S3 is an online storage facility. It is cheap, fast and easy to setup.

S3 handles objects and buckets. An object matches to a stored file. Each object has an identifier, an owner and permissions. Objects are stored in a bucket. A bucket has a unique name that must be compliant with internet domain naming rules. The object identifier is a filename or filename with relative path. With this naming scheme, S3 storage can appear as a regular file system with folders and subfolders.

S3 stores arbitrary objects (computer files) up to 5 terabytes in size, each accompanied by up to 2 kilobytes of metadata. Objects are organized into buckets (each owned by an Amazon Web Services or AWS account) and identified within each bucket by a unique, user-assigned key. Amazon Machine Images (AMIs) which are modified in the Elastic Compute Cloud (EC2) can be exported to S3 as bundles.

Amazon S3 is needed who have the following issues:

Running out of bandwidths

Amazon S3 provides unlimited bandwidth and user be served with any amount of bandwidth the site needs. Charges will be made to credit card and payment can be made at the end of the month.

Better scalability

Amazon S3 using cloud hosting and image serving is relatively fast. Separating them away from normal HTTP request will definitely ease the server load and thus, guarantees better stability.

Store files online

Instead of backing up files in CD/DVDs to save more hard disk space, another option is store them online; user have the option to keep files with them in private or make them publicly accessible.

Easier files retrieval and sharing

If file is online, user can access them from anywhere as long as there’s Internet connection. Amazon S3 also allows one to communicate files with your friends, clients and blog readers in better way.

4.4 Amazon Database Services

Amazon Relational Database Service (Amazon RDS) is a web service that makes it easier to set up, operate and scale a relational database in the cloud. It provides cost-efficient, resizable capacity for multiple industry-standard relational databases and manages common database administration tasks.

Amazon RDS gives us access to the capabilities of a familiar MySQL or Oracle database server. Amazon RDS automatically backs up the database and maintains the database software that powers the DB Instance. Amazon RDS is flexible.

Amazon RDS provides the following advantages:

Accelerated Deployment: Amazon RDS reduces friction, when moving from project conception to deployment.

Can use simple API calls to access the capabilities of a production-ready relational database without worrying about infrastructure provisioning or installing and maintaining database software.

Managed: Amazon RDS handles generic database management tasks.

Compatible: With Amazon RDS, one can get native access to a MySQL or Oracle database server. This means Amazon RDS works with most of your existing tools, applications and drivers. There’s no need to change any code.

Scalable: With a simple API call user can scale the compute and storage resources available to the database to meet business needs and application load.

Reliable: Amazon RDS runs on the same highly reliable infrastructure used by other AWS. Amazon RDS’s automated backup service automatically manages the backup the database and lets us to restore at any point.

Secure: Amazon RDS provides web service interfaces to configure firewall settings that control network access to your database instances and allows SSL connections to the DB Instances.

Inexpensive.

DynamoDB

Amazon DynamoDB is based on the principles of Dynamo, a progenitor of NoSQL and brings the power of the cloud to the NoSQL database world. It offers customers high-availability, reliability and incremental scalability, with no limits on dataset size or request throughput for a given table. And it is fast, also it runs on the latest in solid-state drive (SSD) technology and incorporates numerous other optimizations to deliver low latency at any scale.

Amazon DynamoDB is a NoSQL database service that offers the following benefits:

Managed. DynamoDB frees developers from the headaches of provisioning hardware and software, setting up and configuring a distributed database cluster and managing ongoing cluster operations. It handles all the complexities of scaling and partitions and re-partitions the data over more machine resources to meet your I/O performance requirements.

Scalable. Amazon DynamoDB is designed to scale the resources dedicated to a table to hundreds or even thousands of servers spread over multiple Availability Zones. There are no pre-defined limits to the amount of data each table can store. Developers can store and retrieve any amount of data and DynamoDB will spread the data across more servers as the amount of data stored in the table grows.

Fast. Amazon DynamoDB provides high throughput at very low latency. It is also built on Solid State Drives which help to optimize for high performance even at high scale. Moreover, by not indexing all attributes, the cost of read and write operations is low as write operations involve updating only the primary key index thereby reducing the latency of both read and write operations. An application running in EC2 will typically see average service-side latencies in the single-digit millisecond range for a 1KB object. Most importantly, DynamoDB latencies are predictable. Even as datasets grow, latencies remain stable due to the distributed nature of DynamoDB's data placement and request routing algorithms.

Durable and Highly Available. Amazon DynamoDB replicates its data over at least 3 different data centers so that the system can continue to operate and serve data even under complex failure scenarios.

Flexible. Amazon DynamoDB is an extremely flexible system that does not force its users into a particular data model or a particular consistency model. DynamoDB tables do not have a fixed schema but instead allow each data item to have any number of attributes, including multi-valued attributes. Developers can optionally use stronger consistency models when accessing the database, trading off some performance and availability for a simpler model. They can also take advantage of the atomic increment/decrement functionality of DynamoDB for counters.