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Single System Image
Infrastructure and Tools
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Cluster Computer Architecture
Sequential Applications
Parallel Applications
Parallel Programming Environment
Cluster Middleware(Single System Image and Availability Infrastructure)
Cluster Interconnection Network/Switch
PC/Workstation
Network Interface Hardware
CommunicationsSoftware
PC/Workstation
Network Interface Hardware
CommunicationsSoftware
PC/Workstation
Network Interface Hardware
CommunicationsSoftware
PC/Workstation
Network Interface Hardware
CommunicationsSoftware
Sequential Applications
Sequential Applications
Parallel ApplicationsParallel
Applications
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• Enhanced Performance (performance @ low cost)• Enhanced Availability (failure management)• Single System Image (look-and-feel of one
system)• Size Scalability (physical & application)• Fast Communication (networks & protocols)• Load Balancing (CPU, Net, Memory, Disk) • Security and Encryption (clusters of clusters)• Distributed Environment (Social issues)• Manageability (admin. And control)• Programmability (simple API if required)• Applicability (cluster-aware and non-aware app.)
A major issues in Cluster design
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A typical Cluster Computing Environment
PVM / MPI/ RSH
Applications
Hardware/OS
???
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The missing link is provide by cluster middleware/underware
PVM / MPI/ RSH
Applications
Hardware/OS
Middleware or Underware
PVM / MPI/ RSH
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Middleware Design Goals Complete Transparency (Manageability):
Lets the see a single cluster system.. Single entry point, ftp, telnet, software loading...
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..
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What is Single System Image (SSI)?
SSI is the illusion, created by software or hardware, that presents a collection of computing resources as one, more whole resource.
SSI makes the cluster appear like a single machine to the user, to applications, and to the network.
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Benefits of SSI Use of system resources transparent. 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. No need to be aware of the underlying system
architecture to use these machines effectively.
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Desired SSI Services Single Entry Point:
telnet cluster.my_institute.edu telnet node1.cluster. institute.edu
Single File Hierarchy: /Proc, NFS, xFS, AFS, etc.
Single Control Point: Management GUI Single virtual networking Single memory space - Network RAM/DSM Single Job Management: Glunix, Codine, LSF Single GUI: Like workstation/PC windowing
environment – it may be Web technology
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Availability Support Functions Single I/O space:
Any node can access any peripheral or disk devices without the knowledge of physical location.
Single process Space: Any process on any node create process with
cluster wide process wide and they communicate through signal, pipes, etc, as if they are one a single node.
Checkpointing and process migration: Can saves the process state and intermediate
results in memory to disk to support rollback recovery when node fails. RMS Load balancing...
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SSI Levels SSI levels of abstractions:
Application and Subsystem Level
Operating System Kernel Level
Hardware Level
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SSI at Application and Sub-system Levels
Level Examples Boundary Importance
Application batch system andsystem management
Sub-system
File system
Distributed DB,OSF DME, Lotus Notes, MPI, PVM
An application What a userwants
Sun NFS, OSF,DFS, NetWare,and so on
A sub-system SSI for allapplications ofthe sub-system
Implicitly supports many applications and subsystems
Shared portion of the file system
Toolkit OSF DCE, SunONC+, ApolloDomain
Best level of support for heterogeneous system
Explicit toolkitfacilities: user,service name, time
(c) In search of clusters
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SSI at OS Kernel LevelLevel Examples Boundary Importance
Kernel/OS Layer
Solaris MC, Unixware MOSIX, Sprite, Amoeba/GLunix
Kernelinterfaces
Virtualmemory
UNIX (Sun) vnode,Locus (IBM) vproc
Each name space:files, processes, pipes, devices, etc.
Kernel support forapplications, admsubsystems
None supportingOS kernel
Type of kernelobjects: files,processes, etc.
Modularises SSIcode within kernel
May simplifyimplementationof kernel objects
Each distributedvirtual memoryspace
Microkernel Mach, PARAS, Chorus,OSF/1AD, Amoeba
Implicit SSI forall system services
Each serviceoutside themicrokernel
(c) In search of clusters
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SSI at Hardware Level
memory and I/O
Level Examples Boundary Importance
memory SCI, DASH better communication and synchronization
memory space
SCI, SMP techniques lower overheadcluster I/O
memory and I/Odevice space
Application and Subsystem Level
Operating System Kernel Level
(c) In search of clusters
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SSI Characteristics
Every SSI has a boundary. Single system support can
exist at different levels within a system, one able to be build on another.
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SSI Boundaries
Batch System
SSIBoundary (c) In search
of clusters
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Relationship Among Middleware Modules
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SSI via OS path! 1. Build as a layer on top of the existing OS
Benefits: makes the system quickly portable, tracks vendor software upgrades, and reduces development time.
i.e. new systems can be built quickly by mapping new services onto the functionality provided by the layer beneath. e.g.: Glunix.
2. Build SSI at kernel level, True Cluster OS Good, but Can’t leverage of OS improvements by
vendor. E.g. Unixware, Solaris-MC, and MOSIX.
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SSI Systems & Tools OS level SSI:
SCO NSC UnixWare; Solaris-MC; MOSIX, ….
Middleware level SSI: PVM, TreadMarks (DSM), Glunix,
Condor, Codine, Nimrod, …. Application level SSI:
PARMON, Parallel Oracle, ...
SCO Non-stop Cluster for UnixWare
Users, applications, and systems management
Standard OS kernel calls
Modularkernel
extensions
Extensions
UP or SMP node
Users, applications, and systems management
Standard OS kernel calls
Modular kernel
extensions
Extensions
Devices Devices
ServerNet
UP or SMP node
Standard SCO UnixWare
with clustering hooks
Standard SCO UnixWare
with clustering hooks
Other nodes
http://www.sco.com/products/clustering/
How does NonStop Clusters Work?
Modular Extensions and Hooks to Provide: Single Clusterwide Filesystem view; Transparent Clusterwide device access; Transparent swap space sharing; Transparent Clusterwide IPC; High Performance Internode Communications; Transparent Clusterwide Processes, migration,etc.; Node down cleanup and resource failover; Transparent Clusterwide parallel TCP/IP networking; Application Availability; Clusterwide Membership and Cluster timesync; Cluster System Administration; Load Leveling.
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Sun Solaris MC Solaris MC: A High Performance Operating System for
Clusters A distributed OS for a multicomputer, a cluster of computing
nodes connected by a high-speed interconnect Provide a single system image, making the cluster appear
like a single machine to the user, to applications, and the the network
Built as a globalization layer on top of the existing Solaris kernel
Interesting features extends existing Solaris OS preserves the existing Solaris ABI/API compliance provides support for high availability uses C++, IDL, CORBA in the kernel leverages spring technology
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Solaris-MC: Solaris for MultiComputers
global file system
globalized process management
globalized networking and I/O
Solaris MC Architecture
System call interface
Network
File system
C++
Processes
Object framework
Existing Solaris 2.5 kernel
Othernodes
Object invocations
Kernel
Solaris MC
Applications
http://www.sun.com/research/solaris-mc/
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Solaris MC components Object and
communication support
High availability support
PXFS global distributed file system
Process management
NetworkingSolaris MC Architecture
System call interface
Network
File system
C++
Processes
Object framework
Existing Solaris 2.5 kernel
Othernodes
Object invocations
Kernel
Solaris MC
Applications
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MOSIX: Multicomputer OS for UNIX
An OS module (layer) that provides the applications with the illusion of working on a single system.
Remote operations are performed like local operations.
Transparent to the application - user interface unchanged.
PVM / MPI / RSHMOSIX
Application
Hardware/OS
http://www.mosix.cs.huji.ac.il/ || mosix.org
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Main tool
Supervised by distributed algorithms that respond on-line to global resource availability – transparently.
Load-balancing - migrate process from over-loaded to under-loaded nodes.
Memory ushering - migrate processes from a node that has exhausted its memory, to prevent paging/swapping.
Preemptive process migration that can migrate any process, anywhere, anytime
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MOSIX for Linux at HUJI A scalable cluster configuration:
50 Pentium-II 300 MHz 38 Pentium-Pro 200 MHz (some are SMPs) 16 Pentium-II 400 MHz (some are SMPs)
Over 12 GB cluster-wide RAM Connected by the Myrinet 2.56 G.b/s LAN
Runs Red-Hat 6.0, based on Kernel 2.2.7 Upgrade: HW with Intel, SW with Linux Download MOSIX:
http://www.mosix.cs.huji.ac.il/