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Globus: A Report. Introduction. What is Globus? Need for Globus. Goal of Globus Approach used by Globus: Develop High level tools and basic technologies required for computational grids. Constructing large scale grids using the tools and technologies developed
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Introduction • What is Globus? • Need for Globus. • Goal of Globus • Approach used by Globus: • Develop High level tools and basic technologies required for computational grids. • Constructing large scale grids using the tools and technologies developed • Executing realistic applications to evaluate globus.
Globus Overview • Central element- Globus Metacomputing toolkit. • Toolkit distinguishes between : • Local Services:Kept simple to facilitate development. • Global services:Constructed on top of local services and more complex. • Cause:Must be possible to define new services without changing underlying architecture. • Effect:Globus uses the layered architecture with an “hourglass” shape.
Overview contd. • Interfaces are defined so as to manage heterogeneity rather than hiding it. • An information service is an integral component of the toolkit. • Use standards wherever possible for interfaces and implementation.
Resource Management • Globus Resource Allocation Manager (GRAM) provides the local component for resource management. • Each GRAM responsible for a particular set of “local” resources. • Within GRAM API, resource requests are expressed in terms of an extensible resource specification language (RSL)
Communication • Communication services provided by the Nexus library. • Nexus: A low level API used to support high level communication libraries and languages. • Communication in Nexus is defined in terms of two basic abstractions: • Communication link:Formed by binding a communication start point with a communication end point. • Remote Service Request:Initiates a communication operation.
Communications contd. • Attributes of a start point or an end point control the communication method used on a per link basis. • Use Globus MDS to take decisions on what communication method o use based on dynamic information of the system.
Information • Globus Meta Computing Directory Service (MDS). • Provides suite of tools and API to discover, publish and access information. • Standards used wherever possible (LDAP).
Security • Basic Globus security dealt with just one problem: Authentication. • Two problems of authentication: • Local heterogeneity • N-way security contexts • Local heterogeneity handled by mapping a user’s Globus identity into a local user identity at each resource. • N-way security is handled by asking the user to authenticate just once per computation.
Security contd. • Encrypted channels are not used. Instead Globus relies on Digital Signature mechanism. • Globus security policy is implemented by Globus Security infrastructure (GSI). • All security algorithms coded in terms of Generic Security Service (GSS) standard to provide interoperability. • GSI supports two security mechanisms: • Plaintext Password system • SSL
Other Globus services • Health and Status Monitoring • Remote access to files • Executable management