Grid Computing Software
Interface
• Brief introduction to Globus
• Executing a simple job on command line
• Executing program through a Grid portal
Slides for Grid Computing: Techniques and Applications by Barry Wilkinson, Chapman & Hall/CRC press, © 2009.
Chapter 1, pp 19-28. For educational use only. All rights reserved. Aug 24, 2009
1-2.1
Grid computing infrastructure
(middleware) software
Primary objective:
To make seamless environment for users
to access distributed resources.
1-2.2
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
Globus Project
• Open source software toolkit developed for
Grid computing.
• One of the most influential projects
• Roots in I-way experiment.
• Work started in 1996.
• Four versions developed to present time.
• Reference implementations of Grid
computing standards.
• Defacto standard for Grid computing.
1-2.4
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.).
1-2.5
Some Globus toolkit versions
(approximate time line)
Fig. 1.5
1-2.6
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
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
1-2.8
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.
1-2.9
Security
• 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 so-called (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.
• Users generally will also need accounts of resources they
intend to use (authorization).
1-2.10
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
1a.11
Resource Discovery
• Basic Globus component called 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.
1-2.12
Executing a Job
• Next user typically would want to submit a
job.
• Basic Globus component for running a job is
GRAM (Globus or Grid Resource Allocation
Management).
1-2.13
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 prog1.
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.
1-2.15
GridFTP command to transfer files
globus-url-copy \
gsiftp://www.coitgrid02.uncc.edu/~abw/prog1out \
file:///home/abw/
First argument is source location and second argument is
destination location.
In the above case, the file:
www.coit-grid02.uncc.edu/~abw/prog1out
transferred to
home/abw/
on the local computer.
User employing Globus services and facilities
Fig. 1.6
1-2.17
Grid Portal
Command-line interface a very primitive way of interacting with
Grid resources. Web-based interface called a Grid portal more
desirable. UNC–Charlotte Grid portal course based upon
GridSphere Grid portal toolkit.
Fig. 1.7
Before users can log on, they need a user name and
password for portal.
They must have user “credentials” and accounts on
the resources they wish to access.
In UNC–Charlotte course portal, PURSe (Portalbased User Registration Service) portlet used to
facilitate setup procedures.
Reached by selecting “Register” tab.
User enters required information (name, email
address, institution, etc.) which is forwarded to Grid
system administrator to set up accounts and
credentials.
1-2.19
PURSe
registration
portlet
Fig. 1.8
Registration activities
Fig. 1.9
1-2.21
Once logged into Grid portal, user will see a number
of tabs across top, which enable user to perform
many basic tasks.
Grid information tab
1-2.23
Proxies
To use many services, you are required to have a
proxy certificate (a proxy).
Proxies are part of Grid security infrastructure,
discussed later in course.
Proxy is an electronic document that enables
resources to be accessed on user’s behalf.
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.
1-2.24
Proxy management tab
1-2.25
File management tab
1-2.26
Batch job submission tab
Questions
1a.28
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
1a-2.29
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
1a-2.30
Discussion Question
Is it possible to use the tradition security
method of username/password on a grid?
What problems exist for this method?
1a-2.31