Cloud computing is the present fast developing purpose built architecture created to support computer users. The cloud addresses three main areas of operation: Software as a Service (SaaS) Platform as a Service (PaaS) Infrastructure as a Service (IaaS) By delivering this computing, storage and applications as a service, not a product, the cloud offers both cost and business advantage. The cloud moves all these services offsite to either a contractor, or a centralized facility. Centralizing the data allows the cost to be shared amongst all the users. The cloud accomplishes what IT is always seeking to; increase computing capabilities, without having to provide a new infrastructure. The possible uses of cloud computing are exponential. Users interface with the cloud through their web browser, eliminating the need for installing numerous software applications. Software as a Service (SaaS) In some ways, SaaS is very similar to the old thin-client model of software provision, where clients, in this case usually web browsers, provide the point of access to software running on servers. SaaS is the most familiar form of cloud service for consumers. SaaS moves the task of managing software and its deployment to thirdparty services. Among the most familiar SaaS applications for business are customer relationship management applications like Salesforce, productivity software suites like Google Apps, and storage solutions brothers like Dropbox. Use of SaaS applications tends to reduce the cost of software ownership by removing the need for technical staff to manage install, manage, and upgrade software, as well as reduce the cost of licensing software. SaaS applications are usually provided on a subscription model. Platform as a Service (PaaS) PaaS functions at a lower level than SaaS, typically providing a platform on which software can be developed and deployed. PaaS providers abstract much of the work of dealing with servers and give clients an environment in which the operating system and server software, as well as the underlying server hardware and network infrastructure are taken care of, leaving users free to focus on the business side of scalability, and the application development of their product or service. As with most cloud services, PaaS is built on top of virtualization technology. Businesses can requisition resources as they need them, scaling as demand grows, rather than investing in hardware with redundant resources. Most widely known PaaS providers are AWS Elastic Beanstalk, Windows Azure, Heroku, Force.com, Google App Engine, Apache Stratos.
Infrastructure as a Service (IaaS) Moving down the stack, we get to the fundamental building blocks for cloud services. IaaS is comprised of highly automated and scalable compute resources, complemented by cloud storage and network capability which can be self-provisioned, metered, and available on-demand. IaaS providers offer these cloud servers and their associated resources via dashboard and/or API. IaaS clients have direct access to their servers and storage, just as they would with traditional servers but gain access to a much higher order of scalability. Users of IaaS can outsource and build a virtual data center in the cloud and have access to many of the same technologies and resource capabilities of a traditional data center without having to invest in capacity planning or the physical maintenance and management of it. IaaS is the most flexible cloud computing model and allows for automated deployment of servers, processing power, storage, and networking. IaaS clients have true control over their infrastructure than users of PaaS or SaaS services. The main uses of IaaS include the actual development and deployment of PaaS, SaaS, and web-scale applications.
The 2 main ways of provisioning a cloud infrastructure Public clouds: These are based on shared physical hardware which is owned and operated by thirdparty providers, meaning that there are no hardware or maintenance costs incurred by your business. The ideal solution for small to medium sized businesses or those that have fluctuating demands, the primary benefits of the public cloud are the speed with which you can deploy IT resources, and the utility billing it offers. By spreading infrastructure costs across a number of users, each can operate on a low-cost, pay as you go approach to the provisioning of IT services. And, due to the sheer size of public clouds, businesses can scale compute power up and down as changing business demands dictate, within a matter of minutes. Private clouds: A private cloud is a bespoke infrastructure purely dedicated to your business, hosted either on-site or at a service provider data centre. The private cloud delivers all the agility, scalability and efficiency of the public cloud, but in addition provides greater levels of control and security, making it ideal for larger businesses or those with strict data, regulation and governance obligations. Another key benefit of private cloud is the ability to customise the compute, storage and networking components to best suit your specific IT requirements, something that cannot be achieved so easily in the public cloud environment. Private Cloud Infrastructure A private cloud is owned and operated by a single organisation or institution that controls the way virtualized resources and automated services are customized and used by various departments and constituent groups. Private clouds exist to take advantage of many of cloud s efficiencies, while providing more control of resources and steering clear of multi-tenancy. Key characteristics of private clouds include: A self-service interface that controls common services, allowing IT administrators to quickly provision, allocate and deliver on-demand IT resources Highly automated management of resource pools for everything from compute capability to storage, analytics, and middleware Sophisticated security and governance designed for a company s specific requirements Reduction of costs unlike on-site hosting the price of deploying applications in the cloud can be less due to lower hardware costs from more effective use of physical resources
Universal access - cloud computing can allow remotely located users to access applications and work via the internet Up to date software - ability to upgrade software keeping in mind feedback from previous software releases Choice of applications - This allows flexibility for cloud users to experiment and choose the best option for their needs. Cloud computing also allows a business to use, access and pay only for what they use, with a fast implementation time Potential to be greener and more economical - the average amount of energy needed for a computational action carried out in the cloud is far less than the average amount for an on-site deployment. This is because different organisations can share the same physical resources securely, leading to more efficient use of the shared resources Flexibility cloud computing allows users to switch applications easily and rapidly, using the one that suits their needs best Devising a private cloud plan Designing a cloud operating system environment requires a robust understanding of the requirements and needs of the cloud s users to determine the best possible configuration to meet them. While the hardware choice is important for running many applications smoothly, the services involved in building a cloud infrastructure also requires a great deal of consideration in determining the hardware. If high availability is expected from the cloud, accordingly the configuration of hardware needs to be carefully designed. A cloud infrastructure, if provisioned as a service, which is widely known as Infrastructure as a Service (IaaS), relies on virtual machine technology to deliver servers that can run applications. Virtual servers described in terms of a machine image or instance have characteristics that often can be described in terms of real servers delivering a certain number of microprocessor (CPU) cycles, memory access, and network bandwidth to customers. Virtual machines are containers that are assigned specific resources. The software that runs in the virtual machines is what defines the utility of the cloud computing system.
Private cloud architecture can be widely divided into three parts or components: Virtual hosts, Storage units & Network devices While virtualization is an important technological component of private cloud, the key differentiator is the continued abstraction of computing resources from infrastructure and the machines (virtual or otherwise) used to deliver those resources. Only by delivering this abstraction can customers achieve the benefits of private cloud including improved agility and responsiveness, reduced TCO, and increased business alignment and focus. Most importantly, a private cloud promises to exceed the cost effectiveness of a virtualized infrastructure through higher workload density and greater resource utilization. As open source software is getting widely accepted and implemented in many organisations, the concept of OSS had long since moved from theory to actual practice. Embracing the advantages of its openness, cloud operating system developers are enthused to invest more and more of their resources in this area and thus, today, we have many choices in selecting an evolved and mature cloud OS, OpenStack being one such cloud OS that has been implemented widely across all kinds of organisations. Taking the cue from the three important components required for designing private cloud architecture, OpenStack also has divided its OS into three parts: Compute, Storage & Network, though OpenStack prefers to call these as services run by either a single or multiple servers.
Compute nodes form the resource core of the OpenStack Compute cloud, providing the processing, memory, network and storage resources to run instances. Compute nodes are the workhorse of your cloud and the place where your users' applications will run. Storage nodes are classified into two types: Block Storage & Object Storage. Block storage (sometimes referred to as volume storage) provides users with access to block-storage devices. Users interact with block storage by attaching volumes to their running VM instances. Object Storage provides a highly scalable, highly available storage solution by relaxing some of the constraints of traditional file systems. Block and object storage nodes can be spanned across multiple servers / nodes and can be configured to specific needs of storage requirements. OpenStack Object Storage service is used for creating redundant, scalable data storage using clusters of standardized servers to store petabytes of accessible data. It is a long-term storage system for large amounts of static data that can be retrieved, leveraged, and updated. Object Storage uses a distributed architecture with no central point of control, providing greater scalability, redundancy, and permanence. Objects are written to multiple hardware devices, with the OpenStack software responsible for ensuring data replication and integrity across the cluster. Storage clusters scale horizontally by adding new nodes. Should a node fail, OpenStack works to replicate its content from other active nodes. Because OpenStack uses software logic to ensure data replication and distribution across different devices, inexpensive commodity hard drives and servers can be used in lieu of more expensive equipment. Object Storage is ideal for cost effective, scale-out storage. It provides a fully distributed, API-accessible storage platform that can be integrated directly into applications or used for backup, archiving, and data retention OpenStack provides a rich networking environment that ensures smooth communication between all the nodes. Network nodes are responsible for doing all the virtual networking needed for people to create public or private networks and uplink their virtual machines into external networks. Network nodes form the only
ingress and egress point for instances running on top of OpenStack. They run all of the environment s networking services, with the exception of the networking API service (which runs on the controller node). Cloud controller is the node that orchestrates all the above services and ensures proper communication between the nodes and instances or VMs. The cloud controller provides the central management system for multi-node OpenStack deployments. Typically the cloud controller manages authentication and sends messages to all the systems through a message queue. It has a collection of components that represent the global state of the cloud, talk to services such as authentication, maintain information about the cloud in a database, communicate with all compute nodes and storage workers through a queue, and provide API access. Each service running on a designated cloud controller may be broken out into separate nodes for scalability or availability. Most OpenStack Compute central services and the compute nodes, use a database for stateful information and communicate with each other using the Message Queue. The OpenStack Image Catalog and Delivery service consists of two parts: glance-api and glance-registry. The former is responsible for the delivery of images and the compute node uses it to download images from the back-end. The latter maintains the metadata information associated with virtual machine images and requires a database. The glance-api is an abstraction layer that allows a choice of back-end used when providing storage for deployment images. The OpenStack Dashboard is the graphical control panel for managing the cloud and is implemented as a Python web application that runs in Apache httpd. It is accessed using a web browser via traditional http protocol.
The concepts supporting OpenStack authentication and authorization are derived from well understood and widely used systems of a similar nature. Users have credentials they can use to authenticate, and they can be a member of one or more groups. Keystone is the identity service used by OpenStack for authentication and high-level authorization. It supports token-based authentication and user-service authorization. Utility nodes are used by internal administration staff only to provide a number of basic system administration functions needed to get the environment up and running and to maintain the hardware, OS, and software on which it runs. These nodes run services such as provisioning, configuration management, monitoring, or management software. High Availability systems seek to minimize two things: System downtime Occurs when a user-facing service is unavailable beyond a specified maximum amount of time. Data loss Accidental deletion or destruction of data. Our high availability OpenStack deployment model guarantee protection against system downtime and data loss not only in the event of a single failure, but also against cascading failures, where a single failure deteriorates into a series of consequential failures. A crucial aspect of high availability is the elimination of single points of failure (SPOFs). A SPOF is an individual piece of equipment or software which will cause system downtime or data loss if it fails. In order to eliminate SPOFs, our model provides redundancy of: Network components, such as switches and routers Applications and automatic service migration Storage components In the event that a component fails and a back-up system takes on its load, the high availability system will replace the failed component as quickly as possible to maintain necessary redundancy. This way time spent in a degraded protection state is minimized. However, in the event of multiple independent (non-consequential) failures, our model will protect data over maintaining availability.
Open Standards The use of open standards can help provide interoperability and maximise access to resources and services. Open standards can provide several benefits: Application Independence: To ensure that access to resources is not dependent on a single application. Platform Independence: To ensure that access to resources is not restricted to particular hardware platforms. Long-term Access: To ensure that quality scholarly resources can be preserved and accessed over a long time frame. Architectural Integrity: To ensure that the architectural framework for IT developments is robust and can be further developed in the future. Advantages of using open source software Open source software is free to use, distribute, and modify. It has lower costs, and in most cases this is only a fraction of the cost of their proprietary counterparts. Open source software is more secured as the code is accessible to everyone. Anyone can fix bugs as they are found, and users do not have to wait for the next release. The fact that is continuously analysed by a large community produces secure and stable code. Open source is not dependent on the company or author that originally created it. Even if the company fails, the code continues to exist and be developed by its users. Also, it uses open standards accessible to everyone; thus, it does not have the problem of incompatible formats that exist in proprietary software. The organisations using open source software do not have to think about complex licensing models and do not need anti-piracy measures like product activation or annual subscriptions. The OpenStack private cloud infrastructure allows the users to install and use any OS compatible open source applications, but does not limit them to deploy licensed software like Microsoft development applications, MS Office, Adobe products, AutoDesk products, etc. to name a few. The users can even host any licensed Operating Systems on their VMs for cloud usage.
Acenet edge Acenet, with its technical team having decades of cumulative experience in IT industry, strives to deliver the best of both worlds viz. hardware and software to our customers. This is accomplished by designing servers using excellently engineered cloud-specific hardware components that are integrated and tested by us for this very purpose to meet the overwhelming demands that a high availability cloud environment calls for. The careful selection and integration of these precision components are decided keeping in mind the exact requirement for each of the roles the servers / nodes play and the services they host. Thus we can assure you that not a single server's resources are underutilised nor the configurations oversubscribed. As for software, we are pro-open source whose advantages are already detailed above. Our in-depth understanding and expertise in this area gives us the leverage of selecting the right platform that is tested, evolved, widely used, effectively deployed and stable. The kind of open source platforms like OS flavors & versions and related open source applications & tools that we suggest and implement are anti-lock-in types, by whose virtue the customers have the option of using it in their own way without any consent from its manufacturer, developer or distributor. Acenet's technical team will always be glad to assist you in adapting to new cloud technologies, train your staff hands-on and help in migrating and integrating existing data to the new environment. Our engineers are always in touch with the developer teams of the open source software that we implement for our customers and are active members of the related forums providing solutions to new challenges all along the life cycle of the deployed software. So, in effect, migrating or upgrading the existing infrastructure is done efficiently with minimal or no downtime, wherever possible. Acenet provides post implementation support through phone, e-mail, social networks, remote assistance and/or in person depending of the severity of the issue, which in our experience is a rare occurence, thanks to the choice of components we meticulously make during the designing process. To conclude, if the cloud infratructure you need is a private one, you can count on Acenet to provide you with the best contemporary solution available.