Clusters
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The document discusses computer clusters, which involve linking multiple computers together to work as a single logical unit. Key points include: clusters allow for cost-effective high performance and availability compared to single systems; they can be configured in shared-nothing or shared-disk models; common applications include scientific computing, databases, web services, and high availability systems; and cluster middleware helps provide a single system image and improved manageability.
Clusters
- 3. What is Cluster? Computer Clusters Configuration Applications of Clusters Components Classification Single Sysytem Image Cluster Middleware Benefits of Cluster , SSI & Middle
- 4. A group of the same or similar elements gathered or occurring closely together; a bunch a number of persons or things grouped together a number of things growing, fastened, or occurring close together
- 5. “A computer cluster is a single logical unit consisting of multiple computers that are linked through a LAN and they can be worked as a single system.” The components of a cluster are usually connected to each other through fast local area networks ("LAN"). The networked computers essentially act as a single, much more powerful machine
- 6. Each system has its own CPU, memory, and I/O facilities • Each system is known as a node of the cluster • generally 2 or more computers (nodes) connected together • in a single cabinet, or physically separated & connected via a LAN • appear as a single system to users and applications • provide a cost-effective way to gain features and benefits •
- 7. Shared nothing Model Shared Disk Model The detailed configuration models are:- 1. Shared nothing Model High speed link between nodes No sharing of resources Partitioning of work through division of data Advantage: Reduced communication between nodes Disadvantage: Can result in inefficient division of work
- 8. High speed link between nodes Disk drives are shared between nodes Advantage: Better load balancing Disadvantage: Complex software required for transactional processing
- 11. Technicians working on a large Linux cluster at University of Technology, Germany. Sun Microsystems Cluster
- 12. Clusters are classified into many categories based on various factors as indicated below. Application Target Node Ownership Node Hardware Node Operating System Node Configuration
- 13. Application Target High Performance (HP) Clusters ▪ Grand Challenging Applications High Availability (HA) Clusters ▪ Mission Critical applications
- 14. Node Ownership Dedicated Clusters Non-dedicated clusters ▪ Adaptive parallel computing
- 15. Node Hardware Clusters of PCs (CoPs) Clusters of Workstations (COWs)
- 16. Node Configuration Homogeneous Clusters ▪ All nodes will have similar architectures and run the same OSs Heterogeneous Clusters ▪ All nodes will have different architectures and run different OSs
- 17. Processors Memory and Cache Disk and I/O System Bus
- 18. Aggregated speed with which complex calculations carried out by millions of neurons in human brain is amazing! although individual neurons response is slow (milli sec.)
- 19. • The Single System Image (SSI) represents the view of a distributed system as a single unified computing resource • This provides better usability for the users as it hides the complexities of the underlying distributed and heterogeneous nature of clusters from them A single system image is the illusion, created by software or hardware, that presents a collection of resources as one, more powerful resource. SSI makes the cluster appear like a single machine to the user, to applications, and to the network. • A cluster without a SSI is not a cluster
- 20. Single entry point telnet cluster.my_institute.edu telnet node1.cluster.my_institute.edu Single file hierarchy Single control point: manage from single GUI Single virtual networking Single memory space - DSM Single job management Single user interface 20
- 22. Problem each nodes has a certain amount of resources that can only be used from that node This restriction limits the power of a cluster Solution implementing a middle-ware layer that glues all operating systems on all nodes offer a unified access to system resources 22
- 23. Usage of system resources transparently Transparent process migration and load balancing across nodes. Improved reliability and higher availability Improved system response time and performance Simplified system management Reduction in the risk of operator errors User need not be aware of the underlying system architecture to use these machines effectively
- 24. • A cluster resource management system (RMS) acts as a cluster middleware that implements the SSI for a cluster of machines • It enables users to execute jobs on the cluster without the need to understand the complexities of the underlying cluster architecture • A RMS manages the cluster through four major branches, namely: resource management, job queuing, job scheduling, and job management
- 25. An interface between between use applications and cluster hardware and OS platform. Middleware packages support each other at the management, programming, and implementation levels. Programming enable applications, reduce programming effort, distributed object/component models? Middleware Layers: SSI Layer Availability Layer: It enables the cluster services of ▪ Checkpointing, Automatic Failover, recovery from failure, ▪ fault-tolerant operating among all cluster nodes.
- 26. Complete Transparency (Manageability) Lets the see a single cluster system.. ▪ Single entry point Scalable Performance Easy growth of cluster ▪ no change of API & automatic load distribution. Enhanced Availability Automatic Recovery from failures ▪ Employ checkpointing & fault tolerant technologies Handle consistency of data when replicated..
- 27. Sequential Applications Sequential Applications Sequential Applications Parallel Applications Parallel Applications Parallel Applications Parallel Programming Environment Cluster Middleware (Single System Image and Availability Infrastructure) PC/Workstation PC/Workstation PC/Workstation PC/Workstation Communications Communications Communications Communications Software Software Software Software Network Interface Hardware Network Interface Hardware Cluster Interconnection Network/Switch Network Interface Hardware Network Interface Hardware
- 28. High performance: running cluster enabled programs Scalability: adding servers to the cluster or by adding more clusters to the network as the need arises or CPU to SMP(Symmetric Multiprocessors) High throughput: (cycle) System availability (HA): offer inherent high system availability due to the redundancy of hardware, operating systems, and applications Cost-effectively 28
- 29. Numerous Scientific & engineering Apps. Business Applications: Database Applications (Oracle on clusters). Internet Applications Mission Critical Applications: banks, nuclear reactor control
- 30. The conclusion of this chapter is that although solutions to the resource management and Meta computing problems do exist, none of the solutions is directly applicable to the case in which a user does not have a great deal of knowledge about the system they are using.
- 31. Clusters are promising and fun Offer incremental growth and match with funding pattern New trends in hardware and software technologies are likely to make clusters more promising Cluster-based HP and HA systems can be seen everywhere!
- 32. Summary ?
- 34. High Performance Clusters Linux Cluster; 1000 nodes; parallel programs; MPI Load-leveling Clusters Move processes around to borrow cycles (eg. Mosix) Web-Service Clusters LVS/Piranah; load-level tcp connections; replicate data Storage Clusters GFS; parallel filesystems; same view of data from each node Database Clusters Oracle Parallel Server; High Availability Clusters ServiceGuard, Lifekeeper, Failsafe, heartbeat, failover clusters
Editor's Notes
- #27: application programming interface