An Introduction to Cloud Computing

An Introduction to Cloud Computing Web, as a Platform…

Outline • Web2.0 – The Trends • Cloud Computing • Issues • Applications • Q&A

Web 2.0 • A transformation of web contents from static to dynamic. • Self Publishing / Blogger.com(1999), YouTube(2005) • Feeds / RSS(1999), Atom(2003) • Tagging / del.icio.us(2003), flickr(2004) • Ajax / Gmail(2004), Google Map(2005) • Long Tail / Amazon(1994), AdSense(2005) • Collaboration / Wikipedia(2001), Google docs(2006) • Social / MySpace(2003), Facebook(2004) • MicroBlogging / Twitter(2006), Plurk(2008)

Web 2.0 • The Importance is… • Nowadays, PEOPLE DO SPEND MORE TIME ON THE WEB.

Web as Application • Searching • Authoring • Interaction • Social • …… • And any mix of above

So…? • What do folks care about? • Availability? • Scalability? • Efficiency? • Consistency? • Reliability?

More Insight in SCALABILITY • Why is scalability important? • Server may be down because of overloading. • In ordinary viewpoint, NOT SERVING = USELESS !!!

Heroku, An Example

Cloud?

Cloud Computing • The International Workshop on Cloud Computing(2009) • Cloud Computing is defined as a pool of virtualized computer resources. Based on this virtualization the Cloud Computing paradigm allows workloads to be deployed and scaled-out quickly through the rapid provisioning of virtual machines. A Cloud Computing platform supports redundant, self-recovering, highly scalable programming models that allow workloads to recover from many inevitable hardware/software failures and monitoring resource use in real time for providing physical and virtual servers on which the applications can run. A Cloud Computing platform is more than a collection of computer resources because it provides a mechanism to manage those resources. In a Cloud Computing platform software is migrating from the desktop into the "clouds" of the Internet, promising users anytime, anywhere access to their programs and data.

Cloud Computing(cont.) • Wikipedia • Cloud computing is the provision of dynamically scalable and often virtualized resources as a service over the Internet on a utility basis.[1][2] Users need not have knowledge of, expertise in, or control over the technology infrastructure in the "cloud" that supports them. Cloud computing services often provide common business applications online that are accessed from a web browser, while the software and data are stored on the servers. The term cloud is used as a metaphor for the Internet, based on how the Internet is depicted in computer network diagrams and is an abstraction of the underlying infrastructure it conceals.

Cloud Computing(cont.) • SearchCloudComputing.com • Cloud computing is a general term for anything that involves delivering hosted services over the Internet. These services are broadly divided into three categories: Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). The name cloud computing was inspired by the cloud symbol that's often used to represent the Internet in flow charts and diagrams. A cloud service has three distinct characteristics that differentiate it from traditional hosting. It is sold on demand, typically by the minute or the hour; it is elastic -- a user can have as much or as little of a service as they want at any given time; and the service is fully managed by the provider (the consumer needs nothing but a personal computer and Internet access).

Cloud Computing(cont.) • Accessible with any device with a browser • Focusing on scaling • Easy to use • Elastic (use on demand) • Virtualization

SaaS, IaaS, PaaS • Software as a Service • Search, Amazon, Facebook… • Infrastructure as a Service • Amazon EC2, GoGrid, 3tera… • Platform as a Service • Google AppEngine, Heroku, Aptana

To User • Data can be stored in the cloud • Accessible anywhere • Collaboration • More powerful and efficient

To Developer • More reliable (distributed) data center • More reliable serving • Dynamic scalability • PaaS

Issues • Scalability • Reliability • Data Consistency • Efficiency

Scalability • Scalability • One cannot predict the number of user correctly • Use on demand

Reliability • The service must be persistent and robust. • Load Balancing • Fault-Tolerant • Crash Detection • Self-Recovering Ability

Consistency • Data must be consistent anytime. • No corruption, volatility • Error Checking Mechanism • Redundancy • Locking Mechanism

Efficiency • Cloud leverages computing power to obtain low latency. • Commodity Hardware • Parallelism • Efficient Memory Caching • Bandwidth

Applications • Google Application • MapReduce : Processing • BigTable : Database Management • GFS : Storage • Chubby : Locking service • App Engine : Serving (Now opened !) • Hadoop • Open-source Implementation of MapReduce & GFS

MapReduce • Automatic & efficient parallelization and distribution • Fault-tolerable and robust processing

BigTable • Distributed multi-level sparse map • Reliable database management • Fault-tolerant and Persistent • Highly scalable • Self-load-balancing

Google File System(GFS) • Reliable and efficient data storage. • High performance to mutation. • File chunks are replicated for backup. • Master/Chunk-server mechanism

Chubby • Coarse-grained Locking Service • Fault-tolerance file management • Paxos consensus Algorithm

AppEngine • IaaS + PaaS • Purchase additional resources if needed. • High scalability, efficiency, and reliability.

Cloud Computing To Smart Home? • A robust and efficient statistic center and processing center. • A stronger monitoring ability. • More service availability. • Fault-tolerance mechanism. • And more!

Q & A • Any feedback or problems?

An Introduction to Cloud Computing