cloud_load balancing.ppt
- 2. PRESIDENCY COLLEGE 2 Chapter – I Introduction Essentials Benefits Business and IT Perspective Cloud and Virtualization Cloud Service Requirements Cloud and Dynamic Infrastructure Cloud Computing Characteristics Cloud Adoption Cloud Models Measured Service Security
- 3. PRESIDENCY COLLEGE 3 Cloud Computing refers to applications and services that run on a distributed network using virtualized resources and accessed by common Internet protocols and networking standards. It is distinguished by the notion that resources are virtual and limitless and that details of the physical systems on which software runs are abstracted from the user.
- 4. PRESIDENCY COLLEGE 4 Defining Cloud Computing Cloud computing takes the technology, services and applications that are similar to those on the Internet and turns them into a self-service utility. The use of the word cloud makes reference to the two essential concepts.
- 5. PRESIDENCY COLLEGE 5 Essentials Abstraction: cloud computing abstracts the details of system implementation from users and developers. Applications run on physical systems that aren’t specified, data is stored in locations that are unknown, administration of systems is outsourced to others and access by users is ubiquitous.
- 6. PRESIDENCY COLLEGE 6 Essentials Virtualization: Cloud computing virtualizes systems by pooling and sharing resources. Systems and storage can be provisioned as needed from a centralized infrastructure, costs are assessed on a metered basis, multi- tenancy is enabled, and resources are scalable with agility.
- 7. PRESIDENCY COLLEGE 7 To help clarify how cloud computing has changed the nature of commercial system deployment, consider these three examples:
- 8. PRESIDENCY COLLEGE 8 Google: In the previous decade, Google has built a worldwide network of datacenters to service it search engine. In doing so Google has captured a substantial portion of the world’s advertising revenue. That revenue has enabled Google to offer free software to users based on that infrastructure and has changed the market for user-facing software. This is the classic Software as a Service case.
- 9. PRESIDENCY COLLEGE 9 Azure Platform: By contrast, Microsoft is creating the Azure Platform. It enables .NET Framework applications to run over the Internet as an alternate platform for Microsoft developer software running on desktops.
- 10. PRESIDENCY COLLEGE 10 Amazon Web Services: One of the most successful cloud-based businesses is Amazon Web Services, which is an Infrastructure as a Service offering that lets you rent virtual computers on Amazon’s own infrastructure.
- 11. PRESIDENCY COLLEGE 11 These new capabilities enable applications to be written and deployed with minimal expense and to be rapidly scaled and made available worldwide as business conditions permit. This is truly a revolutionary change in the way enterprise computing is created and deployed.
- 12. PRESIDENCY COLLEGE 12 Benefits of Cloud Computing On-demand self-service: A client can provision computer resource without the need for interaction with cloud-service provider personnel. Broad network access: Access to resources in the cloud is available over the network using standard methods in a manner that provides platform- independent access to clients of all types.
- 13. PRESIDENCY COLLEGE 13 Benefits of Cloud Computing Resource pooling: a cloud service provider creates resources that are pooled together in a system that supports multi-tenant usage. Physical and virtual systems are dynamically allocated or reallocated as needed. Intrinsic in this concept of pooling is the idea of abstraction that hides the location of resources such vm, memory, processing, storage, network and connectivity.
- 14. PRESIDENCY COLLEGE 14 Benefits of Cloud Computing Rapid elasticity: Resources can be rapidly and elastically provisioned. The system can add resources by either scaling up systems (more powerful computers) or scaling out systems. From the standpoint of client, cloud computing resources should look limitless and can be purchased at any time and in any quantity.
- 15. PRESIDENCY COLLEGE 15 Benefits of Cloud Computing Measured service: The use of cloud system resources is measured, audited and reported to the customer based on a metered system. A client can be charged based on a known metric such as amount of storage used, number of transactions, network I/O or bandwidth, amount of processing power used and so forth. A client is charged based on the level of services provided.
- 16. PRESIDENCY COLLEGE 16 Advantages • Ease of utilization • Lower costs • Quality of service • Reliability • Outsourced IT management • Simplified maintenance and upgrade • Lower barrier to entry
- 17. PRESIDENCY COLLEGE 17 Cloud and Virtualization When you use cloud computing, you are accessing pooled resources using a technique called virtualization. Virtualization assigns a logical name for a physical resource and then provides a pointer to that physical resource when a request is made. Virtualization provides a means to manage resources effectively because the mapping of virtual resources to physical resources can be both dynamic and facile. Virtualization is dynamic in that the mapping can be assigned based on rapidly changing conditions and it is facile because changes to a mapping assignment can be nearly instantaneous.
- 18. PRESIDENCY COLLEGE 18 These are among the different types of virtualization that are characteristics of cloud computing: Access: A client can request access to a cloud service from any location. Application: A cloud has multiple application instances and directs requests to an instance based on conditions. CPU: Computers can be partitioned into a set of virtual machines with each machine being assigned a workload. Alternatively, systems can be virtualized through load-balancing technologies. Storage: Data is stored across storage devices and often replicated for redundancy.
- 19. PRESIDENCY COLLEGE 19 To enable these characteristics, resources must be highly configurable and flexible. You can define the features in software and hardware that enable this flexibility as conforming to one or more of the following mobility patterns: P2V: Physical to Virtual V2V: Virtual to Virtual V2P: Virtual to Physical P2P: Physical to Physical D2C: Datacenter to Cloud C2C: Cloud to Cloud C2D: Cloud to Datacenter D2D: Datacenter to Datacenter
- 20. PRESIDENCY COLLEGE 20 Virtualization is a key enabler of the first four of five key attributes of cloud computing: Service-based: A service-based architecture is where clients are abstracted from service providers through service interfaces. Scalable and elastic: Services can be altered to affect capacity and performance on demand. Shared services: Resources are pooled in order to create greater efficiencies. Metered usage: Services are billed on a usage basis. Internet delivery: The services provided by cloud computing are based on Internet protocols and formats.
- 21. PRESIDENCY COLLEGE 21 Load Balancing and Virtualization: One characteristic of cloud computing is virtualized network access to a service. No matter where you access the service, you are directed to the available resources. The technology used to distribute service requests to resources is referred to as load balancing. Load balancing is an optimization technique; it can be used to increase utilization and throughput, lower latency, reduce response time and avoid system overload. The following network resources can be load balanced: • Network interfaces and services such as DNS, FTP and HTTP • Connections through intelligent switches • Processing through computer system assignment • Storage resources • Access to application instances
- 22. PRESIDENCY COLLEGE 22 Without load balancing, cloud computing would be very difficult to manage. Load balancing provides the necessary redundancy to make an intrinsically unreliable system reliable through managed redirection. It also provides fault tolerance when coupled with a failover mechanism. Load balancing is nearly always a feature of server farms and computer clusters and for high availability applications. Load balancer uses: • Round robin scheduling algorithms to handle the service request queues. • Session ticket to maintain subsequent related traffic from the client that is part of that session can be properly routed to the same resource. • Persistent session data • Client-side cookies.
- 23. PRESIDENCY COLLEGE 23 Advanced Load Balancing: The more sophisticated load balancers are workload managers. They determine the current utilization of the resources in their pool, the response time, the work queue length, connection latency and capacity, and other factors in order to assign task to each resource. Among the features you find in load balancers are polling resources for their health, the ability to bring standby servers online, workload weighing based on a resource’s capacity, HTTP traffic compression, TCP offload and buffering, security and authentication, and packet shaping using content filtering and priority queuing. An Application Delivery Controller (ADC) is a combination of load balancer and application server that is a server placed between a firewall or router and a server farm providing web services. An ADC is assigned a virtual IP address VIP that it maps to a pool of servers based on application specific criteria.