Grid Basics CS7803 Notes

1
Grid BasicsCS-780-3 Notes

• In courtesy of Chaman Singh Verma

2
Outline

• Introduction to Grid
• Grid applications
• Grid Architecture
• Synergy with other technologies
• Discussion
• Total Slides 49
• Paper Authors Ian Foster , Carl Kasselman
• Steven Tuecke Jeffrey M. Nick

3
Power Generation

• Past
• Till the end of 19th Century, power
  generation was considered a local luxury. Only
  rich could generate them into their backyards.
• Present
• We take electricity for granted, without
  knowing the sources and complexities of
  distribution. We use the services and pay for it.
  Many of the countries provide high Quality of
  Service.
• Future
• We want to break the 19th century model in
  computer usages. We want
• to provide a service model in computation and
  storage similar to power
• generation.

4
What is Grid ? Checklist

• A Grid is a system that
• Coordinates resources that are not subject to
  centralized control (not for each single node)
• Uses standard, open, general-purpose protocols
  and interfaces.
• Provide high quality of services
• Reference What is the Grid ? By Ian Foster

5
Grid A Virtual Organization

• Grid resource sharing paradigm has greater
  scope than P2P system. Grid implicitly allow
  direct access to computers, software, data and
  any other resources.
• Both providers and consumers define clearly
  what they will share, who can share and
  conditions under which sharing will take place.
• A set of individuals and/or institutions
  defined by such sharing rules form what we call
  Virtual Organization.

6
Grid An Evolution, not revolution
Source IBM Grid Computing

• Grid can be seen as the latest and most
  complete evolution of more familiar
• development.
• Like the Web
• Grid keeps complexity hidden
  multiple users enjoy a single unified experience.
• Unlike the Web
• enables full collaboration toward
  real business goal.
• Like Peer-to-Peer
• It allows user to share files.
• Unlike Peer-to-Peer
• Not only files, but everything which
  could be shared .
• Like Clusters and distributed computing
• It bring computing resource together.
• Unlike Clusters and distributed Computing
• Grid can be geographically distributed
  and heterogeneous.
• Like Virtualization technologies
• enables virtualization of IT
  resources.
• Unlike Virtualization technologies
• It can enable virtualization of vast
  and disparate resources.

7
Originally Targeted Applications

• What types of applications will grid be used for
  ?
• Distributed Supercomputing
• High-throughput Computing
• Cracking cryptosystems
• On-demand Computing
• NetSolve, large archives
• Data-Intensive Computing
• Sloan Digital Sky Survey, Weather forecasting
• Collaborative Computing
• Insors, GriPhyN, SciRUN

8
Grid Problem Defined

• Grid problem is defined as Coordinated resource
  sharing and problem solving in dynamic,
  multi-institutional virtual organizations.
• The sharing raises many issues which were not
  addressed by distributed computing for example
• How to structure flexible transient
  relationships.
• How to structure fine grained access control over
  resources taking care of local and global
  policies.
• How to agree on quality of service, scheduling
  and co-allocation.

9
Top 500 Supercomputers (June 2003)
Earth Simulator NEC Yokohama 35.86 TFlops
ASCI Q LANL Los Alamos HP Alphaserver SC
13.88 TFlops
MCR Linux Cluster LLNL Livermore, 7.634 TFlops
ASCI White LLNL, Livermore IBM SP Power3, 7.304
TFlops
Seaborg NERSC/LBNL, Berkeley, IBM SP Power3,
7.303 TFlops
Source http//www.top500.org
10
Latest News Nov 8,2003

• Virginia Tech. Big Mac replaced 3rd position. It
  consists of 1100 Macintosh PCs and performed 17
  TFlops.

11
General highlights from Top 500 (June 2003)

• 157 systems reported to have peak performance
  above 1 TFlops.
• Total accumulated performance is 375 TFlops. ( up
  from 293 TFlops )
• Entry level performance is 245.1 GFlops. (Up from
  195.8)
• A Total of 119 systems (up from 56) uses Intel
  processors.
• 149 systems are now labeled as clusters ( up from
  53 )
• 23 of them are self-made ( Up from 14 )
• Among top 10, 7 from US, 2 from Japan, 1 from
  France.

12
Economics and Control

• The infrastructures are very expensive and
  require years of hard work.
• The shear force of economics will require that
  these resources are under strict control and are
  optimally utilized.
• Many times freedom is costly and chaotic.
• This is the starting what we call Grid
  Computing

13
Changing face of Enterprise Computing

• Most of the recent, enterprise systems are
  collection of heterogeneous resources.
• Quality of services traditionally associated with
  mainframe centric computing are now essential to
  the effective conduct of e-business across
  distributed resources, inside as well as outside
  the enterprise.
• Recently there is upsurge of services providers
  of various types such as web-hosting SP, storage
  SP, application SP
• All these require standardization.

14

• Birds Eye view
• In the next few slides, we will get some
  broader picture followed by technical details.

15
Web Services Architecture
Universal Description, Discovery and Integration
(UDDI) allows us to find Web Services which meet
certain requirements.
Web Services Description Language Web-Services
must be Self-describing and should Tell the
invoker about operations it supports and How to
invoke it.
Simple Object Access Protocol Message passing
between client and server using SOAP.
Note UDDI, WSDL, SOAP and HTTP are just an
examples. Different implementations can use
different technologies.
16
A Typical Web Service Invocation
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End Users perspective
18
Stateless machines
The above model is stateless. It can not remember
what is done from one invocation to
another. One client can mess up the another
clients operations.
19
Factories

• The concept of factories solves the problems
  mentioned earlier.
• Make Grid Stateful Machine
• Create transient services

20
Web Service Application
Client and Server stubs are generated
automatically from the specifications.
21
Technical Details

• Service A service is a network-enabled entity
  that provides a specific capability. ( example
  the ability to move files, create processes or
  verifying access rights.
• Service protocols behavior
• Grid services are defined by OGSA ( Open Grid
  Services Architecture). (OpenGrid Forum)
• Grid services are specified by OGSI ( Open Grid
  Services Infrastructure)
• Globus Toolkit is the most popular open
  implementation of OGSA.

22
Major Players in Grid Service World
23
Example from NetSolve

• Suppose you want to multiply Matrix A and
  Matrix B. There is one site which provides the
  facility. You may want to directly integrate the
  function in your software.
• request netsolve( matmul, a, b)
• C netsolve( wait, request)

24
Nature of Grid Architecture

• Grid architecture is a set of protocols for
  establishment, management and usage of dynamic,
  cross-organizational virtual organizations.
• The main issues in the architecture are
• Interoperability
• Standard Protocols
• Services
• Application Programming Interface( API) and
  Software Development Kits (SDK)

25
Hourglass Model

• Narrow neck of glass defines
• a small set of core abstractions
• and protocols. It consists of
• protocols for
• Connectivity
• Resource Management
• These protocols must be chosen
• so as to capture the fundamental
• mechanism of sharing across
• many different types.

26
Grid Architecture
Fabric layer implements the local, resource
Specific operations that occurs on specific
Resources. Connectivity protocols are concerned
with communication and authentication. Resource
protocols are concerned with negotiating access
to individual resources Collective protocols and
services are concerned with coordinating use of
multiple resources.
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General list of services

• Identity Authentication
• Authorization policy
• Resource discovery
• Resource characterization
• Resource allocation
• Co-reservation, workflow
• High-Speed data transfer
• Remote data access

• Performance guarantees
• Monitoring
• Adaptation
• Intrusion detection
• Resource Management
• Accounting and payment
• Fault management

28
Resource Management

• At the minimum the following resource should
  be
• available for query
• Computational
• Mechanism for starting program, monitoring
  and controlling the execution, advanced
  reservations, hardware and software
  characteristics, state information such as
  current load etc.
• Storage
• Mechanism for putting and getting files,
  state information such as available space and
  bandwidth utilization.
• Network
• Mechanism for control over resource
  allocation for network transfer, information
  about network characteristics and load
• Code Repositories
• Management for versioned source and object
  code. ( CVS style)
• Catalogs

29
Connectivity Layer

• This layer defines core communications and
  authentication protocols.
• Communication protocols enable the exchange of
  data between different fabric layers. It include
  transport, routing and naming services.
• Authentications protocols build on
  communication services to provide
  cryptographically secure mechanisms for verifying
  the identity of users and resources.

30
Authentication Characteristics

• Single sign on
• Single log on should be sufficient for
  access to multiple grid resources.
• Delegation
• run a program on users behalf.
• Integration with local security
• example Kerberos or Unix security
• User-based trust relationships.
• If an user uses services from multiple
  service providers at the same time, the security
  mechanism should not require that each of the
  resource providers to cooperate and interact with
  each other.

31
Resource layer

• It is built on top of communications. It
  defines protocols for
• Secure negotiation
• Initiations
• Monitoring
• Control
• Accounting
• Payment for sharing resources.

32
Resource Layer

• Information protocols are used for obtaining
  information about structure and state of a
  resource. ( current load, usage policy,
  configuration etc)
• Management protocols are used to negotiate
  access to shared resource, specifying resource
  requirements
• Advanced reservation
• Quality of service.
• Operations to perform

33
Collective Coordinating Multiple Resources

• Directory Services
• A user may query for resource by name and/or
  by its attributes such as type, availability,
  load.
• Co-allocation, scheduling and brokering services
• allow VO participants to request for some
  specific resources for some specific purpose and
  duration.
• Monitoring and Diagnostic services
• allows monitoring for resource failure, attacks,
  overload etc
• Data replication services
• allows management of VO storage to maximize
  data access performance with respect to some
  metric such as response time, reliability and
  cost.

34
Collective

• Grid-enabled programming systems
• enable familiar programming models to be used
  in Grid environment using other grid services
  such as resource discovery, security etc. etc.
• example Globus MPI
• Workload management and collaboration
• Allow problem solving environment.
• Software discovery
• allows selection of the best software
  implementations and execution platform. Example
  NetSolve and Ninf
• Accounting and payment services
• gather usage information for the purpose of
  accounting, payment for the services.

35
Collective
36
OGSA

• Build on both Grid and Web-Services
  communities, OGSA defines uniform service
  semantic called Grid Services.
• OGSA defines few persistent and many transient
  services
• OGSA defines interfaces for managing Grid service
  instances.
• Factory, registry, discovery, lifetime
• The OGSA defines interfaces and behavior for
• Reliable invocation, lifetime management,
  discovery, authorization,
• notification, upgradeability, concurrency,
  manageability
• OGSA also defines WSDL interface and associated
  convention.
• Protocols for reliable and secure management of
  distributed state.

37
Need for service oriented view

• It allows us to address the need for standard
  interface definition, local/remote transparency
  and adaptation to local OS.
• It allows multiple protocols bindings to
  facilitate localized optimization of services.
• It simplify virtualization which in turn also
  allows consistent resource access multiple
  heterogeneous platform.
• With service oriented view, we can partition the
  interoperability into two sub-problems, namely
  the definition of service interface and
  identification of protocols that can be used to
  invoke a particular interface

38
Globus Toolkit

• Globus toolkit is an open-architecture and
  open-source set of services and software
  libraries that support Grid and Grid
  applications.
• This toolkit address issues of security,
  information discovery, resource management, data
  management, communication, fault detection and
  portability.
• GRAM Grid Resource Allocation and
  Management
• MDS Meta Directory Service
• GSI Grid Security Infrastructure
• This toolkit will be described in detail in
  the next presentation, therefore I will skip any
  more description.

39
Nature of Service

• Services are location transparent.
• Services are created and destroyed dynamically.
• Services are stateful. Every service is assigned
  a globally unique name, called Grid Service
  Handle (GSH)
• Grid services can change during their lifetime (
  for example support new protocols).

40
Web Services

• Web services are the basis for Grid services
  which are the cornerstones of OGSA and OGSI.
• Web Services use simple Internet based protocols
  to address heterogeneous distributed computing.
• Web Services define a technique for describing
  software components to be accessed, methods for
  accessing them and discovery about the
  components.
• Web Services are language, programming model and
  system software neutral.

41
Web Services

• Presently, this word has been over-used and
  become a buzz-word.
• There is distinction between website and web
  services. Although web services rely on
  web-technologies, they have no relation to web
  browsers and HTML.
• Website is for humans, Web services are for
  software.

42
Web Services

• RMI, CORBA, EJB etc etc are oriented towards
  highly coupled distributed systems, where the
  client and servers are dependent on each other,
  web-services are oriented towards loosely coupled
  systems, where the client might have no prior
  knowledge of the Web Service until it actually
  invokes it.

43
Web services Advantages and disadvantages

• Web services are platform and language
  independent, since they use rely on XML.
• Most Web services use HTTP for transmitting
  messages, and most of the internet proxies and
  firewalls do not mess with HTTP traffic.
• Overhead are high Transmitting XML is
  expensive. No real-time application will use web
  service using this model.
• Lack of versatility Currently provide basic
  services compared to CORBA

44
Service Lifetime Management

• Who terminates transient state services ?
• In normal circumstance, the request from the
  service invoker, but in distributed machine it is
  difficult. Component may fail, messages may be
  lost.
• OGSA solves this problem using Soft State.
  Every service is created with a specified
  lifetime which can be extended by the request
  from client or other grid service. If no request
  is received, service is automatically terminated.
• Soft state lifetime management avoids
• Explicit client teardown of complex state
• Resource leaks in hosting environment.

45
Lifetime management

• OGSA has SetTermination operation within
  GridService interface.
• The use of absolute time in lifetime management
  implies existence of global clock that is well
  synchronized.
• Network Time Protocol (NTP) provide standardized
  mechanisms for clock synchronization ( Up-to tens
  of milliseconds)

46
Upgradeability

• Services within the complex systems must be
  independently upgradeable.
• Versioning and compatibility between services
  must be managed and expressed so that clients can
  discover not only the specific service versions
  but also compatible services.
• OGSA defines conventions that allow us to
  identify when a service changes and when those
  changes are backwardly compatible with respect to
  interface and semantics.

47
Notification

• OGSA notification framework allow clients to
  register interest in being notified of particular
  message using asynchronous, one-way delivery.
• OGSA defines common abstraction and interfaces
  for NotificationSource and NotificationSink

48
Some myths (misunderstanding) about Grid Computing

• Grid is next generation Internet.
• The grid is a source of free cycles.
• Grid requires a distributed operating system.
• Grid requires a new programming model.
• Grid makes high-performance computing
  superfluous.

49
Distributed Computing Economics (Views of Jim
Gray)

• An equivalent price for following items
• one data base access
• 10 bytes of internet traffic
• 100,000 instructions
• 10 bytes of disk storage
• a megabyte of disk bandwidth
• Break-even point is 10,000 instructions / byte.
• This serves a basis how we do cost-effective
  Internet-based computing, such as grid computing.

50
How are the numbers computed?

• A 2GH CPU with 2 GB RAM box 2,000
• A 200 GB disk,100 accesses/s, or 50MB/s 200
• 1 Mbps WAN link 100/month
• 1 is equivalent to
• 3.24 GB sent over WAN (7.2 hours)
• 100 Tera CPU instructions 7.2 hours of CPU
  time
• 1 GB disk
• 2.592 million database accesses (in 7.2 hours)
• 1.296 Tera Byte disk bandwidths (in 7.2 hours)
  

51
Cycle-based Computing is Almost Free

• The accumulated cycles in SETI_at_Home are 54
  Teraflops.
• Google freely provides a trillion searches a year
  from the largest database (2 peterbytes).
• Hotmail freely carries a trillion e-mails per
  year.
• Amazon.com offers a free book search tool.
• Many well-known media sites offer free news
• The maintenance prices paid are low and worthy.
  

52
What is SETI_at_Home?

• It uses millions of computers in homes/offices
  world wide to analyze radio signals from space.
• SETI Search for Extraterrestrial Intelligence is
  to detect intelligent life outside Earth.
• Uses radio telescope to listen (collect) for
  narrow-bandwidth radio signals from space.
• Data analysis (1) computing power spectrums, (2)
  finding candidate signals, (3) eliminating
  meaningless signals.
• Embarrassing Parallelism CPU and Data Intensive,
  but infrequent communications. (high bandwidths
  interconnects in supercomputers are not
  necessary!)

53
Who are paying thefree Computing

• Advertisers pay it.
• Google, hotmail, amazon.com collect 1 from a
  company for profits if its site is visited 1,000
  time via these free services Cost Per
  thousand iMpressions (CPM).
• Big companies are eager to pay maintenance.
• Low cost but very effective promotion.
• A Web site almost becomes the only Spoke-man.
• SETI_at_Home rely on donated cycles world wide.
• It provided a 1,300 years of free computing on
  2/3/03.

54
Cases for Grid Computing at least 10,000 Ins/Byte

• A cryptographic search problem
• only a few Kbytes input/output, but computing for
  days.
• A representative job submitted to SETI_at_Home
• computing on 12 hours on 1/2 Mbytes of input
• A CFD computation at Cornell
• 7 years computing for 100 MB of input, 10 GB
  output.
• Making animated movie of Toy Story
• a 200 MB image to take several hours to render.
  (200,000-600,000 Ins/Byte).

55
Grid Computing Should Follow the Economics

• Suitable Applications can be very limited.
• A good solution to send a GB over Internet to
  save years of computing. It is not economic to
  send a KB if the result can be computed locally
  in a second.
• If Internet cost drops slower than Moores Law,
  the analysis becomes stronger.
• Over the 40 years, network cost fallen much
  slower.
• Cluster computing has different economics
• a GBps Ethernet costs 200/port, delivers 50 MBps
• it is comparable to disk bandwidth cost, 10,000
  lower than Internet costs. (so the CFD fits
  better on clusters).

56
Opportunities for challenges

• It seems to me that most of challenges in Grid
  are related to management or development of
  applications which need Grid.
• In my view, I do not see any challenging issues
  which are specific to Grid. Application,
  networking, Internet protocols are changing
  orthogonally. Therefore success of Grid depends
  on success of their components.
• How successful will be Grid in future ? Well,
  keep mum about future.

57

• Thanks