Cloud computing
- 1. Your Coffee Shop Uses Cloud Computing M.A student : Ali Reza Khosh Zaban In The Name Of Allah
- 2. What is the cloud? Where is the cloud? Are we in the cloud now? • The cloud is just a metaphor for the Internet • storing and accessing data and programs over the Internet instead of your computer's hard drive • Network Attached Storage (NAS) • My Cloud • cloud computing can be done anywhere, anytime.
- 3. Your Coffee Shop Uses Cloud Computing • For fundamental cloud computing patterns, we show that coffee shops similarly handle the five design phases of cloud applications: 1. decomposition 2. Workload 3. data (state) 4. component refinement 5. elasticity and resiliency. • In other words, you can experience all the design phases first-hand by buying a coffee.
- 5. Phase 1: Decomposition • Clouds are large distributed systems providing resources for computation, communication, and storage. • The best practice for decomposing application functionality is captured by the distributed application pattern.
- 6. the distributed application pattern • This pattern summarizes three decomposition strategies 1. Layer‐based decomposition • for example, user interface , processing , and data handling layers 2. Process‐based decomposition • such as the Business Process Execution Language (BPEL) or Business Process Model and Notation (BPMN). 3. pipes‐and‐filters-based decomposition • The coffee shop uses the third decomposition strategy • user interface, coffee processing, and special processing for frozen coffee
- 7. Phase 2: Workload • The workload the application experiences substantially affects its development after decomposition • Logical application components are commonly grouped and assigned to multiple tiers. for example, to multiple virtual servers • In a Cloud environnent, tiers can commonly scale independently.
- 8. Five workload patterns • Static workload • Periodic workload • Once‐in‐a‐lifetime workload • Unpredictable workload • Continuously changing workload
- 9. In Your Coffee Shop • In the coffee shop, the user group generates periodic workload • Peaks occur in the morning when customers start their day, and in the afternoon when school is out. • the severity of the peaks differs significantly due to the processing complexity. • The result queue rarely needs to store a lot of finished products.
- 11. Phase 3: Data (State) • As a prerequisite : 1. The location where data are stored 2. Data consistency are extremely important • We differentiate two types of state: 1. Session state for example, a shopping basket in an online shop 2. Application state such as the customer data, the currently processed orders
- 12. Phase 3: Data (State) • Strict consistency Data is stored at different locations to improve response times and avoid loss in case of failures, while replica consistency is ensured at all times • Eventual consistency Performance and data availability during network partitioning are enabled by ensuring data consistency eventually and not at all times.
- 13. In Your Coffee Shop 1. Session state Where is my coffee? Where is the coffee for Chris? 2. Application state Coffee, Chai, Mocha,… 3. Eventual consistency It will be ready in about five minutes. lie a little bit as the business case allows.
- 14. Phase 4: Component Refinement • We must refine the application’s functional aspects 1. User interface component Handle the synchronous interaction with human users 2. Processing component Functionality is made configurable to support different customer requirements.
- 15. Processing component in a coffee shop • How the application can handle these processing requests by keeping them in a queue and spreading them among multiple processing components. • Baristas will take cups from the request queue, handle the order, and put the finished coffee in the result queue.
- 16. Your Coffee Shop / Your cloud • Coffee shop employees aren’t as flexible as most cloud resources. Calling them to come to work and sending them home every few minutes would be impractical • Therefore, coffee shops usually ensure that employees can fulfill different roles: baristas can help out as employees at cash registers and vice versa.
- 17. Phase 5: Elasticity and Resiliency • The last design phase for cloud applications considers how components are provisioned and decommissioned to meet the current workload and cope with failures. • For elastic scalability, IT architects must first determine the current workload and reflect it by adjusting resource numbers
- 18. Availability using the following two patterns 1. Node‐based availability A cloud provider guarantees that individual nodes are available such as individual virtual servers, middleware components, or hosted application components. 2. Environment‐based availability A cloud provider guarantees that the environment hosting individual nodes such as virtual servers or hosted application components , will be available. • Through redundancy, the application’s availability can increase.
- 19. Scalability and resiliency are also important in the coffee shop • Number of customers • Coffee cups awaiting processing • Node‐based availability The coffee machine • Environment‐based availability The overall set of employees • Fail number of workers Sickness Restroom breaks Deterioration of the machine And so on
- 20. References • Your Coffee Shop Uses Cloud Computing Christoph Fehling, Frank Leymann, and Ralph Retter • University of Stuttgart • www.cpmag.com