1-2.1 Grid computing infrastructure software Brief introduction to Globus © 2010 B. Wilkinson/Clayton Ferner. Spring 2010 Grid computing course. Modification date: Jan 17, 2010

Primary objective: To make seamless environment for users to access distributed resources Grid computing infrastructure software

Key aspects include: Secure envelop over all transactions Single sign-on - being able to access all available resources and run jobs without having to supply additional passwords or account information. Data management tools 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 interface 1-2.3

1-2.4 Globus Project Open source software toolkit developed for Grid computing. One of the most influential projects Roots in I-way experiment. Work started in Four versions developed to present time. (Version 5 being developed for We will not consider 5.0 until stable.) Reference implementations of Grid computing standards. Defacto standard for Grid computing.

1-2.5 Globus A “toolkit” of services and packages for creating the basic grid computing infrastructure Higher level tools added to this infrastructure Version 4 is web-services based Some non-web services code exists from earlier versions (legacy) or where not appropriate (for efficiency, etc.).

1-2.6 Some Globus toolkit versions (approximate time line) Fig. 1.5 Globus 5.0

Globus Toolkit 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 1-2.7

Data Management Security Common Runtime Execution Management Information Services Web Services Components Non-WS Components Pre-WS Authentication Authorization GridFTP Grid Resource Allocation Mgmt (Pre-WS GRAM) ‏ Monitoring & Discovery System (MDS2) ‏ C Common Libraries GT2GT2 WS Authentication Authorization Reliable File Transfer OGSA-DAI [Tech Preview] Grid Resource Allocation Mgmt (WS GRAM) ‏ Monitoring & Discovery System (MDS4) ‏ Java WS Core Community Authorization Service GT3GT3 Replica Location Service XIO GT3GT3 Credential Management GT4GT4 Python WS Core [contribution] C WS Core Community Scheduler Framework [contribution] Delegation Service GT4GT4 Globus Open Source Grid Software I Foster

1.2.9 Each part comprises a set of web services and/or non-web service components. Some built upon earlier versions of Globus.

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 MDS (Monitoring and Discovery Service)‏ –To discover resources and their status GridFTP –For transferring files between resources

Security 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.

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)

1a.13 Resource Discovery 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

Resource Discovery 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

Executing a Job Users typically want to submit jobs for execution. Basic Globus component for running a job is GRAM (Globus or Grid Resource Allocation Management)

Command-line interface Grid computing environments mostly Linux-based and originally accessed through a command line. 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 prog

Executing a Job (continued)‏ May be necessary beforehand to transfer files to resources and afterwards to transfer files to other locations including back to user. User might use data management component called GridFTP for that

GridFTP command to transfer files globus-url-copy \ gsiftp:// \ file:///home/abw/ First argument is source location and second argument is destination location. In the above case, the file: transferred to home/abw/ on the local computer

User employing Globus services and facilities Fig. 1.6

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

Example Gridsphere portal– used in this course. We started with the portal and will then go though command line and behind-the-scenes activities.

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. Very convenient to use credential management service called myProxy to hold proxies Usually, Gridsphere automatically obtains a proxy from the myProxy server for you when you log in.

Proxy management tab

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

Question: Which of the following is not provided for directly in the Globus version 4 software? (a) Execution management (b) Accounting (c) Network security (d) Resource discovery (e) File transfers

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

Question: What does GRAM do?

Question: What does MDS do?

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

Discussion Question Is it possible to use the tradition security method of username/password on a grid? What problems exist for this method?