Globus Computing Infrustructure Software

Globus Toolkit

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Grid computer software infrastructure

• Primary objective: to makes a seamless environment for users to access distributed resources.

• Key aspects:– Secure envelope – over all transactions– Single sign-on – being able to access all available

resources after providing credentials ONCE– Data Management– Information services - providing characteristics of

resources and their status (including dynamic load)– APIs and services that enable applications themselves

to take advantage of Grid platform– Convenient User Interfaces (??)

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Globus Project• Open source software toolkit developed for Grid

computing.• Roots in I-way experiment – led by Ian Foster• Work started in 1996. • Now up to Version 5• Reference implementations of Grid computing

standards.• Defacto standard for Grid computing and one of

the most influential projects

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Globus Toolkit• “Toolkit” of services and packages for

creating basic grid computing infrastructure. One may use parts of the toolkit as needed.

• Five major parts:– Common run time - Libraries and services – Security - Components to provide secure access– Execution management - Executing, monitoring and

management of jobs– Data Management - Discovery access and transfer of data– Information - Discovery and monitoring of resources and

services

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Globus Toolkit Version

• Version 1 essentially a research prototype not widely used• Version 2 widely used - not web-service based• Version 3 web service based but not widely accepted because

of the way services were implemented and non-robustness• Version 4 is web-service based. Some non-web services code

exists from earlier versions (legacy) or where not appropriate to change to web-service based (for efficiency, etc.).

• Version 5 returned to non-web service approach of version 2.

• We are using Globus Version 4.0 as it is mature, widely used, and we did not want to incur new software problems in class.

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Timeline of Globus Toolkit

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Globus 5.0.0

Globus 5.0.4

2011

Globus Open Source Grid Software Version 4

1-2 7Data

ManagementSecurity

CommonRuntime

Execution Management

Information Services

Web Services

Components

Non-WS

Components

Pre-WSAuthenticationAuthorization

GridFTP

GridResource

Allocation Mgmt(Pre-WS GRAM)

Monitoring& Discovery

System(MDS2)

C CommonLibraries

GT2

WSAuthenticationAuthorization

ReliableFile

Transfer

OGSA-DAI[Tech Preview]

GridResource

Allocation Mgmt(WS GRAM)

Monitoring& Discovery

System(MDS4)

Java WS Core

CommunityAuthorization

ServiceGT3

ReplicaLocationService

XIO

GT3

CredentialManagement

GT4

Python WS Core[contribution]

C WS Core

CommunitySchedulerFramework

[contribution]

DelegationService

GT4

I Foster

Major Globus 5 changes over version 4

“Most components of GT5 are incremental updates (numerous bug fixes and new features) over their GT4 counter-parts (e.g. GridFTP, RLS, MyProxy, GSI-OpenSSH”

Some components taken out: GT4 Java Core, WS-GRAM4, RFT, to be replaced.

GRAM implementation -- pre-WS GRAM2 code base and GRAM2 compatibile.

NO WEB SERVICE COMPONENTS

1-2 8http://www.globus.org/toolkit/docs/5.0/5.0.0/rn/

1-2 9http://www.globus.org/toolkit/about.html

Currently not showing information services in version 5. New Globus crux project will address this.

Some basic Globus components

• GSI Grid Security Infrastructure– Provides for security envelop around Grid resources– Uses public key cryptography

• GRAM (Globus/Grid Resource Allocation Management)– Globus’ basic execution management component – Used to issue and manage jobs

• GridFTP– For transferring files between resources

• MDS (Monitoring and Discovery Service)– To discover resources and their status

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Security Issues

• Has to cross administrative domains.• Need agreed mechanisms and

standards.• Focus on Internet security

mechanisms, modified to handle the special needs of Grid computing.

• Distributed resources must be protected from unauthorized access.

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GSI (Grid Security Infrastructure)Globus components for creating security envelop

• Requires each user to be authenticated (their identity proved)

• Uses public key cryptography (basis of Internet security)

• Each user must possess a (digital) certificate, signed by a trusted certificate authority.

• Users will also need to be able to give their authority to Grid components to act on their behalf – so-called proxy certificates, see later.

• Users generally will also need accounts on resources they intend to use (authorization).

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Resource DiscoveryGlobus MDS (Monitoring and

Discovery System)

• Users might access MDS to discover status of compute resources. In practice, users often know what resources are there but not dynamic load.

• MDS might be used by other Grid components such as schedulers. 1-2 13

• Still primitive and in research but ideal is to be able to submit a job and the system find the best grid resources for that job across the whole grid

Executing a JobGRAM (Globus or Grid Resource Allocation

Management)

• Users typically want to submit jobs for execution.

• Grid computing environments mostly Linux-based and originally and still commonly accessed through a command line.

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Job submission command-line interface

•Once you have established your security credentials, to run a simple job you might issue GRAM command:

globusrun-ws -submit -c prog1 *where prog1 is executable of job.

•Executable needs to be present on compute resource that is to execute it.•Above command does not specify compute resource and hence computer executing globusrun-ws command will execute prog1.

1-2 15* Globus 5 command is globusrun (not a web service)

GridFTP command to transfer filesglobus-url-copy \

gsiftp://www.coitgrid02.uncc.edu/~abw/prog1out \file:///home/abw/

First argument -- source locationSecond argument -- destination location.

In the above case, the file:www.coit-grid02.uncc.edu/~abw/prog1out

transferred to home/abw/prog1out

on the local computer.

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Scenario of User employing Globus services and facilities

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Grid portals• Command-line interface a very primitive way of

interacting with Grid resources.• Portal offers a higher-level Web based interfaces to

accessing and controlling grid resources and to communicate with other members of Virtual Organization

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Gridsphere

• Gridsphere is a toolkit to build a portal• We are starting with a portal. Next we will use

the command line• Later we will have an assignment of building a

portal

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Proxies

• To use many services, you are required to have a proxy certificate (a proxy), derived from your user certificate.

• Proxies enables resources to be accessed on user’s behalf.

• Proxies are part of Grid security infrastructure, discussed later in course.

• A credential management service called myProxy is used to hold proxies

• Usually, Gridsphere automatically obtains a proxy from the myProxy server for you when you log in.

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Proxy management tab

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Questions

Quiz

Question: What is meant by "single sign-on"?

(a) Allowing only one person to sign onto a computer

(b) Not allowing a person to log onto a computer more than once in any one period

(c) A mechanism in which a user does not need to sign again to acquire additional resources.

(b) None of the other answers

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Question: What is authentication and what is authorization? What’s the difference?

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Question: What does GRAM do?

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Question: What does MDS do?

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Question: What compoent in the Globus toolkit provides the means to transfer files?

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Discussion Question

Is it possible to use the tradition security

method of username/password on a grid?

What problems exist for this method?

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