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 –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