A public cloud is one based on the standard cloud computing model. Resources such as applications and storage are made available to the public over the internet by the service providers. Public cloud services may be free or offered on a pay-per-usage model and by using software as a service (SaaS) reduces ownership cost. Comparing cloud computing with dedicated hosting comes up with mixed responses. The advantages of cloud include low cost, fast provisioning, easy manageability and high scalability. We don’t have to worry about the initial set-up cost for the hardware or software for loadbalancing as these are managed by the cloud computing platform providers The major concerns about public cloud include - Data privacy and integrity, Service availability, Moving data between service providers etc. Since public cloud computing is available to anybody, the concerns about the risk of security breach is high. This is where the Private Cloud overtakes the Public Cloud concept. While public Cloud is offered as a service over the internet, the private cloud is a deployment within a firewall and is maintained by the concerned enterprise. Public cloud’s advantage includes low upfront cost and infinite scalability while the main concerns are with accountability, security, and lock-in.

Some of the main public cloud providers include Amazon Web Services, Rackspace and GoGrid.

AWS

Amazon was founded in 1994 and is headquartered in Seattle, Washington. It has direct international operations in the United States, Canada, France, Germany, Japan, and the United Kingdom. Since 2004, Amazon has begun to rapidly expand its web services arsenal. Products such as Amazon EC2 and Amazon S3, Amazon Route 53 have been large successes. Some of Amazon’s recent acquisitions include Shopbop (2006), Abebooks (2008), Zappos (2009), LOVEFiLM (2011). As of Q1 2011, Amazon has approximately 137 million active customers worldwide.

Amazon Web Services has been the pioneers in cloud computing. Since early 2006, Amazon Web Services (AWS) has provided companies of all sizes with an infrastructure web services platform in the cloud. AWS manages datacenters in 7 different regions of the world and allow clients to use the computing resources over the internet on a pay-per-usage model. They also provide a Management console for the users to manage their resources from the web. Apart from this AWS also provide services like loadbalancing, easy manageability in the web console. Amazon.com website itself is running on the AWS. .

Amazon EC2 (Elastic compute Cloud)

EC2 is a web service from AWS that provides resizable compute capacity in the cloud. It presents a virtual computing environment; allowing us to launch instances with a variety of operating system, load them with our application and manage our access permissions. AWS datacenters are situated in 7 different regions all over the world. Amazon provides a collection of pre-configured templated images including – Linux ( centos, Redhat, ubuntu, debian, suse etc.) and Windows ( Windows Server® 2003 R2, 2008 and 2008 R2 etc) with which we can launch our instances. SparkSupport can help you migrate your current applications running on traditional servers to Amazon EC2 instances. We will calculate your resource usage need and select the correct instance type required for the smooth running of your application.

Amazon S3 ( Amazon Simple Storage Service )

It is the storage service over the internet from AWS. It is designed to provide 99.999999999% durability and 99.99% availability of objects over a given year. Pay for only for what we use. A storage directory here is called by the name 'bucket'. The data can be stored/retrieved from anywhere anytime using an HTTPS protocol over the internet. S3 can be used as a secure off instance storage for the data. In your application if you want to store static contents S3 will be a good choice, the option is to save your static files on s3 buckets and access it via URL. Since AWS is providing different regions you can even setup a CDN like service by making it to serve your static contents from the regions near the user accessing your application.

Amazon EBS (Amazon Elastic Block Store )

Provides block level storage volumes for use with Amazon EC2 instances. These are off-instance Storage which persists even after the instance is shutdown. We can create storage volumes from 1 GB to 1 TB that can be mounted as devices on our EC2 instances.

Amazon RDS (Amazon Relational Database Service)

Makes it easy to set up, operate, and scale a relational database in the cloud. This is a dedicated database instance and we will be getting only database access. RDS supports MySql and Oracle databases. Automated backups are turned on by default. MySql provides replication option also. Amazon RDS is tightly integrated with other Amazon Web Services. Low latency database access is possible for applications running on EC2. The main intention of RDS design is to reduce the manual administrative tasks for the database.

Elastic Load Balancing (ELB)

ELB automatically distributes incoming application traffic across multiple Amazon EC2 instances located in same/different availability zones and help you achieve greater fault tolerance for your applications. You are charged for each hour or partial hour your Elastic Load Balancer is running and for each GB of data transferred through your Elastic Load Balancer.

ELB detects health of Amazon instances and when it detects unhealthy load-balanced Amazon EC2 instances, it no longer routes traffic to those Amazon EC2 instances and spread the load across the remaining healthy Amazon EC2 instances.

RackSpace

Rackspace US, Inc. (NYSE: RAX) is an IT hosting company based in San Antonio, Texas. They are one of the worlds leading hosting and cloud computing provider. The company started in 1998. Now the company is having over 110,000 cloud computing customers. Openstack, a massively scalable cloud operating system is founded by Rackspace Hosting and NASA. Openstack is an answer from Rackspace to build an operating system to power both public and private clouds. Rackspace also supports private clouds that run outside of its datacenters provided these clouds run OpenStack and use the specified hardware. Rackspace is also involved with the Open Compute Project which is a project started at Facebook with a goal to build one of the most efficient computing infrastructures at the lowest possible cost. In the future we might see a combination of OpenStack and Open Compute.

Cloud Hosting

Rackspace Hosting services are supported by nine data centers located in the U.S., the UK and Hong Kong. Rackspace supports 18 different operating systems including Centos, Debian, Fedora, Gentoo, OpenSUSE, RedHatEL, Ubuntu, Windows Server 2008. RackSpace also offer a web based easy implementing cloud solution like AWS; but the server types and pricing varies. Cloud Server sizes are measured by the amount of physical memory reserved for the instance and range from 256 MB up to 30 GB.

Cloud Files

This is an unlimited storage solution over the internet from rackspace. The access to the stored data is controlled by a control panel. Cloud Files is powered by OpenStack. It also supports fast content delivery using Akamai's Content Delivery Network. This storage solution comes with a pay-per-usage model. The data can be made public or private on our choice. Cloud Drive is another storage service from Rackspace as a replacement for file servers. It offers storing, sharing , syncing, and automatic backing up files. Rackspace Server Backup is another similar initiative that allows a secure server backup and online data management with an easy-to-use software.

Cloud Loadbalancers

Rackspace offers an on demand loadbalancing solution which we can purchase, configure and drop according to our requirements. High-availability functionality is built-in to the loadbalancing application. A single cloud load balancer is connected via 10Gb/second network to both public and Rackspace's internal network. Rackspace claims about 9Gb/second of actual throughput from their tests.

Private Cloud Solution

Rackspace provides an option for creating private cloud powered by the powerful tool built by them called OpenStack. A dedicated environment can be created in Customer datacenter or in a chosen Rackspace datacenter or the partner datacenters. Self-service portal for instantly provisioning resources is associated with it.

Cloud DNS

Domain Name System management through APIs. We can manage domains, sub-domains, and records via the REST-based API. Also we can manage mail servers, zone delegation, and create SPF records etc. It is easy to migrate DNS configurations to and from Rackspace.

OnApp

Cloud offering has been the survival mantra for most of the hosting companies and datacentres these days. Ever wondered how to build an Iaas Cloud service just like Amazon and google is providing ? Will it fit within your budget to build a full-fledged cloud service which provides end-to-end solutions to the customers at the same time can compete with the big players in pricing and user-experience ?

There comes the answer to all your questions Onapp the cloud software.

Its obvious that you will be having heterogeneous hardwares of servers and storage devices and Onapp helps in pooling these resources and make that to a cloud which can be provisioned on demand to clients or end users.

Onapp provides a complete cloud hosting infrastructure, besides that this software provides functionality for the management of cloud resources, including virtual machines, hypervisors, SANs and networks; end user accounts, permissions and limits; pricing and billing calculations for cloud resources; and failover between different hypervisors in the cloud.

Recently Onapp rebranded its CDN services as OnApp CDN Federation by roping in all the cloud providers who uses Onapp and facilitating the CDN service to the end customers by collaborating the infra of the onapp cloud providers. This is one of the most innovative thinking which has shown the traction recently in the cloud business and all the competitors of onapp cloud are closely watching this initiative.

Onapp Architecture

A brief overview of the software
OnApp Cloud software uses hardware virtualization/ paravirtualization methods to enable the deployment of multiple types of cloud hosting infrastructure: public clouds, private clouds, hybrid clouds and VPS clouds. Another great feature of it is that, it also allows hosts to offer traditional VPS hosting with local storage. OnApp describes its software as a multi-tenant tool with multi-cloud and multi-hypervisor support, and multi-OS support for virtual machines.

The features of OnApp Cloud include:

• A highly user friendly GUI management interface, used by administrators to manage the cloud, and by customers to order and configure cloud resources
• Fully Automatic hypervisor failover
• Rapid IaaS enablement: cloud infrastructure can be deployed within a short span of time
• User access level, limits and user roles engine
• Co-hosting of multiple variants of x86 and x64 Windows and Linux virtual machines
• Rapid virtual machine deployment using templates (a template in OnApp is a preconfigured OS image)
• A variety of hypervisor support lik Xen, KVM and VMware
• Utilizing Hypervisor, data store and network zones, which can be used to create private clouds and availability zones
• To offer Pay as you go model, Utility (hourly) billing for CPU, RAM, storage, bandwidth, IOPS and IP resources, as well as plan-based billing (e.g. monthly)
• Integration to popular hosting billing software, including HostBill, WHMCS and Ubersmith
• Support for varied storage that presents a block device, including RAID, LVM, iSCSI, Fiber and local storage
• A RESTful xml and JSON API

Onapp's Products

OnApp provides everything you need to build a global cloud business, in one integrated platform. You get a complete cloud management system with a built-in SAN, a global CDN, a hosted DNS service, load balancing, autoscaling, metering, billing, user management and much more, included as standard.

Everything you need to design and deliver public cloud, VPS cloud, hybrid and virtual private cloud services. It's a complete cloud management and orchestration platform, designed to remove the entry barriers to the cloud for service providers.

Everything you need to create your own CDN service, and a new source of revenue accelerating apps, video and content for your clients. It's a federated CDN that gives you instant access to capacity in locations all over the world.

Everything you need to build enterprise-class storage for your cloud, using off-the-shelf servers, disks and network components. It's a distributed SAN designed for cloud providers, with intuitive control of striping & redundancy and close to raw disk performance.