First Steps to Cloud Development

Traditional infrastructure generally necessitates predicting the amount of computing resources your application will use over a period of several years. If you under-estimate, your applications will not have the horsepower to handle unexpected traffic, potentially resulting in customer dissatisfaction. If you over-estimate, you’re wasting money with superfluous resources.

first steps to cloud development

The on-demand and elastic nature of the cloud approach (Automated Elasticity), however, enables the infrastructure to be closely aligned (as it expands and contracts) with the actual demand, thereby increasing overall utilization and reducing cost.

Elasticity is one of the fundamental properties of the cloud. Elasticity is the power to scale computing resources up and down easily and with minimal friction. It is important to understand that elasticity will ultimately drive most of the benefits of the cloud. As a cloud architect, you need to internalize this concept and work it into your application architecture in order to take maximum benefit of the cloud.

Traditionally, applications have been built for fixed, rigid and pre-provisioned infrastructure. Companies never had the need to provision and install servers on daily basis. As a result, most software architectures do not address the rapid deployment or reduction of hardware. Since the provisioning time and upfront investment for acquiring new resources was too high, software architects never invested time and resources in optimizing for hardware utilization. It was acceptable if the hardware on which the application is running was under-utilized. The notion of “elasticity” within an architecture was overlooked because the idea of having new resources in minutes was not possible.

With the cloud, this mindset needs to change. Cloud computing streamlines the process of acquiring the necessary resources; there is no longer any need to place orders ahead of time and to hold unused hardware captive. Instead, cloud architects can request what they need mere minutes before they need it or automate the procurement process, taking advantage of the vast scale and rapid response time of the cloud. The same is applicable to releasing the unneeded or under-utilized resources when you don’t need them.

If you cannot embrace the change and implement elasticity in your application architecture, you might not be able to take the full advantage of the cloud. As a cloud architect, you should think creatively and think about ways you can implement elasticity in your application. For example, infrastructure that used to run daily nightly builds and perform regression and unit tests every night at 2:00 AM for two hours (often termed as the “QA/Build box”) was sitting idle for rest of the day. Now, with elastic infrastructure, one can run nightly builds on boxes that are “alive” and being paid for only for 2 hours in the night. Likewise, an internal trouble ticketing web application that always used to run on peak capacity (5 servers 24x7x365) to meet the demand during the day can now be provisioned to run on-demand (5 servers from 9AM to 5 PM and 2 servers for 5 PM to 9 AM) based on the traffic pattern.

Designing intelligent elastic cloud architectures, so that infrastructure runs only when you need it, is an art in itself. Elasticity should be one of the architectural design requirements or a system property. Question that you need to ask: What components or layers in my application architecture can become elastic? What will it take to make that component elastic? What will be the impact of implementing elasticity to my overall system architecture?

In the next section, you will see specific techniques to implement elasticity in your applications. To effectively leverage the cloud benefits, it is important to architect with this mindset.

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Cloud computing is the use of computing resources (hardware and software) that are delivered as a service over a network (typically the Internet). The name comes from the use of a cloud-shaped symbol as an abstraction for the complex infrastructure it contains in system diagrams. Cloud computing entrusts remote services with a user's data, software and computation.

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There are many different providers offering you to enjoy all benefits of the cloud hosting environment. Each provider has specific offerings for cloud computing technology users. As of today, one of the leaders in this sector is Amazon AWS with approx. 60% of the market. Although, honestly, the Amazon’s interface often is not so easy to work with right now, but the rest of the benefits for users is way on top of the competitors providing similar services.

Meantime, we can observe other providers closely focusing on service support and user-friendly interface, so depending on your specific needs you might want to consider them as well.

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Zero upfront infrastructure investment: If you want to build a large-scale system, it may cost a fortune to invest in real estate, physical security, hardware (racks, servers, routers, backup power supplies), hardware management (power management, cooling), and operations personnel. Because of huge upfront investments, the project would typically require several rounds of management approvals before it could even be kicked off. Now, the utility-style cloud computing has extenuated the problem of fixed costs or startup costs inflating the initial project budget.

Just-in-time Infrastructure: In the past, if your application had become popular with a lot of users and you failed in scaling up your systems or infrastructure you would unavoidably become a victim of your own success. On the other hand, if you had invested heavily without any success, you would become a victim of your flop. By deploying applications in-the-cloud with just-in-time self-provisioning, you do not have to worry about pre-procuring capacity for large-scale systems. This increases agility, lowers risk and lowers operational cost because you scale only as you grow and only pay for what you use.

More efficient resource utilization: System administrators usually worry about procuring hardware (when they run out of capacity) and higher infrastructure utilization (when they have excess and idle capacity). With the cloud, they can manage resources more effectively and efficiently by having the applications request and relinquish resources on-demand.

Usage-based costing: With utility-style pricing, you are billed only for the infrastructure that has been used. You are not paying for allocated but unused infrastructure. This adds a new dimension to cost savings. You can see immediate cost savings (sometimes as early as your next month’s bill) when you deploy an optimization patch to update your cloud application. For example, if a caching layer can reduce your data requests by 70%, the savings begin to accrue immediately and you see the reward right in the next bill. Moreover, if you are building platforms on the top of the cloud, you can pass on the same flexible, variable usage-based cost structure to your own customers.

Reduced time to market: Parallelization is the one of the great ways to speed up processing. If one compute-intensive or data-intensive job that can be run in parallel takes 500 hours to process on one machine, with cloud architectures, it would be possible to spawn and launch 500 instances and process the same job in 1 hour. Having available an elastic infrastructure provides the application with the ability to exploit parallelization in a cost-effective manner reducing time to market.

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Automation – “scriptable infrastructure”: You can create repeatable build and deployment systems by leveraging programmable (API-driven) infrastructure.

Auto-scaling: You can scale your applications up and down to match your unexpected demand without any human intervention. Auto-scaling encourages automation and drives more efficiency.

Proactive scaling: Scale your application up and down to meet your anticipated demand with proper planning understanding of your traffic patterns so that you keep your costs low while scaling.

More efficient development lifecycle: Production systems may be easily cloned for use as development and test environments. Staging environments may be easily promoted to production.

Improved testability: Never run out of hardware for testing. Inject and automate testing at every stage during the development process. You can spawn up an “instant test lab” with pre-configured environments only for the duration of testing phase.

Disaster recovery and business continuity: The cloud provides a lower cost option for maintaining a fleet of DR servers and data storage. With the cloud, you can take advantage of geo-distribution and replicate the environment in other location within minutes.

“Overflow” the traffic to the cloud: With a few clicks and effective load balancing tactics, you can create a complete overflow-proof application by routing excess traffic to the cloud.

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The Amazon Web Services (AWS) cloud provides a highly reliable and scalable infrastructure for deploying web-scale solutions, with minimal support and administration costs, and more flexibility than you’ve come to expect from your own infrastructure, either on-premise or at a datacenter facility.

AWS offers variety of infrastructure services today. The diagram below will introduce you the AWS terminology and help you understand how your application can interact with different Amazon Web Services and how different services interact with each other.

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Instances can be launched in one or more geographical regions. Each region has multiple Availability Zones. Availability Zones are distinct locations that are engineered to be insulated from failures in other Availability Zones and provide inexpensive, low latency network connectivity to other Availability Zones in the same Region.

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Amazon Elastic Compute Cloud (Amazon EC2) is a web service that provides resizable compute capacity in the cloud. You can bundle the operating system, application software and associated configuration settings into an Amazon Machine Image (AMI).

You can then use these AMIs to provision multiple virtualized instances as well as decommission them using simple web service calls to scale capacity up and down quickly, as your capacity requirement changes. You can purchase

On-Demand Instances in which you pay for the instances by the hour or Reserved Instances in which you pay a low, one-time payment and receive a lower usage rate to run the instance than with an On-Demand Instance or Spot Instances where you can bid for unused capacity and further reduce your cost.

You can also distribute incoming traffic by creating an elastic load balancer using the Elastic Load Balancing service.

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Elastic IP addresses allow you to allocate a static IP address and programmatically assign it to an instance. You can enable monitoring on an Amazon EC2 instance using Amazon CloudWatch in order to gain visibility into resource utilization, operational performance, and overall demand patterns (including metrics such as CPU utilization, disk reads and writes, and network traffic). You can create Auto-scaling Group using the Auto-scaling feature to automatically scale your capacity on certain conditions based on metric that Amazon CloudWatch collects.

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Amazon Elastic Block Storage (EBS) volumes provide network-attached persistent storage to Amazon EC2 instances. Point-in-time consistent snapshots of EBS volumes can be created and stored on Amazon Simple Storage Service (Amazon S3).

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Amazon S3 is highly durable and distributed data store. With a simple web services interface, you can store and retrieve large amounts of data as objects in buckets (containers) at any time, from anywhere on the web using standard HTTP verbs. Copies of objects can be distributed and cached at 14 edge locations around the world by creating a distribution using Amazon CloudFront service – a web service for content delivery (static or streaming content).

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Amazon SimpleDB is a web service that provides the core functionality of a database- real-time lookup and simple querying of structured data - without the operational complexity. You can organize the dataset into domains and can run queries across all of the data stored in a particular domain. Domains are collections of items that are described by attribute-value pairs.

Amazon Relational Database Service (Amazon RDS) provides an easy way to setup, operate and scale a relational database in the cloud. You can launch a DB Instance and get access to a full-featured MySQL database and not worry about common database administration tasks like backups, patch management etc.

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Amazon Simple Queue Service (Amazon SQS) is a reliable, highly scalable, hosted distributed queue for storing messages as they travel between computers and application components.

Amazon Simple Notifications Service (Amazon SNS) provides a simple way to notify applications or people from the cloud by creating Topics and using a publish-subscribe protocol.

Amazon Elastic MapReduce provides a hosted Hadoop framework running on the web-scale infrastructure of Amazon Elastic Compute Cloud (Amazon EC2) and Amazon Simple Storage Service (Amazon S3) and allows you to create customized JobFlows. JobFlow is a sequence of MapReduce steps.

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Amazon Virtual Private Cloud (Amazon VPC) allows you to extend your corporate network into a private cloud contained within AWS. Amazon VPC uses IPSec tunnel mode that enables you to create a secure connection between a gateway in your data center and a gateway in AWS.

All AWS infrastructure services offer utility-style pricing that require no long-term commitments or contracts. For example, you pay by the hour for Amazon EC2 instance usage and pay by the gigabyte for storage and data transfer in the case of Amazon S3. More information about each of these services and their pay-as-you-go pricing is available on the AWS Website.

Note that using the AWS cloud doesn’t require sacrificing the flexibility and control you’ve grown accustomed to:

You are free to use the programming model, language, or operating system (Windows, OpenSolaris or any flavor of Linux) of your choice.

You are free to pick and choose the AWS products that best satisfy your requirements—you can use any of the services individually or in any combination.

Because AWS provides resizable (storage, bandwidth and computing) resources, you are free to consume as much or as little and only pay for what you consume.

You are free to use the system management tools you’ve used in the past and extend your datacenter into the cloud.

Conclusion: Moving Your App to the AWS Cloud

AWS specific tactics for implementing this best practice:

  1. Failover gracefully using Elastic IPs: Elastic IP is a static IP that is dynamically re-mappable. You can quickly remap and failover to another set of servers so that your traffic is routed to the new servers. It works great when you want to upgrade from old to new versions or in case of hardware failures;
  2. Utilize multiple Availability Zones: Availability Zones are conceptually like logical datacenters. By deploying your architecture to multiple availability zones, you can ensure highly availability. Utilize Amazon RDS Multi-AZ deployment functionality to automatically replicate database updates across multiple Availability Zones;
  3. Maintain an Amazon Machine Image so that you can restore and clone environments very easily in a different Availability Zone; Maintain multiple Database slaves across Availability Zones and setup hot replication;
  4. Utilize Amazon CloudWatch (or various real-time open source monitoring tools) to get more visibility and take appropriate actions in case of hardware failure or performance degradation. Setup an Auto scaling group to maintain a fixed fleet size so that it replaces unhealthy Amazon EC2 instances by new ones;
  5. Utilize Amazon EBS and set up cron jobs so that incremental snapshots are automatically uploaded to Amazon S3 and data is persisted independent of your instances;
  6. Utilize Amazon RDS and set the retention period for backups, so that it can perform automated.

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