low level grid services (job management, data management, monitoring services)
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December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Low Level Grid Services (Job Management, Data Management, Monitoring
Services)
Ravi K MadduriArgonne National Laboratory
University of Chicago
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Services Overview
• Installation• Data Management
– GridFTP, RFT, RLS, DAIS
• Resource Management– Schedulers, logs, sudo
• Information Services– Index service hierarchies,
ganglia/hawkeye
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Full Toolkit Installation• Binaries available for many platforms
– Apple– Linux
• Debian, Fedora, SuSe, RHEL, Redhat– FreeBSD– HP/UX, Tru64– AIX– Solaris– Windows (Java code only)
• Source code also available• See http://www.globus.org/toolkit/docs/4.0 for
installation guide, quickstart, and pre-req documentation
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Overview of GT4 Data Services
• GridFTP– High-performance Data transfer protocol
• The Reliable File Transfer Service (RFT)– Data movement services for GT4
• The Replica Location Service (RLS)– Distributed registry that records locations of
data copies
• The Data Access and Integration Service (DAIS)– Service to access relational and XML databases
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
What is GridFTP?• A secure, robust, fast, efficient, standards based,
widely accepted data transfer protocol• A Protocol
– Multiple Independent implementation can interoperate• This works. Both the Condor Project at Uwis and
Fermi Lab have home grown servers that work with ours.
• Lots of people have developed clients independent of the Globus Project.
• The Globus Toolkit supplies a reference implementation:– Server– Client tools (globus-url-copy)– Development Libraries
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
GT4 GridFTP Implementation
•Based on XIO•Extremely modular to allow
integration with a variety of data sources (files, mass stores, etc.)
•Striping support is provided in 4.0
•Has IPV6 support included (EPRT, EPSV)
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Configuring GridFTP
• Right configuration results in better performance
• Add entries to /etc/services and (x)inetd
• Configuration options:– Binding to a specific
interface/address– Striped backend– TCP tuning parameters
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
What is RFT ?• WS-RF compliant Fault-tolerant, High-
performance data transfer service– Soft state.– Notifications/Query
• Reliability on top of high performance provided by GridFTP.– Fire and Forget.– Integrated Automatic Failure Recovery.
• Network level failures.• System level failures etc.
– Essentially a Data transfer scheduler with FIFO as a Queue Policy.
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
What is RFT (Continued..)?
RFT Service
RFT Client
SOAP Messages
Notifications(Optional)
DataChannel
Protocol Interpreter
MasterDSI
DataChannel
SlaveDSI
IPCReceiver
IPC Link
MasterDSI
Protocol Interpreter
Data Channel
IPCReceiver
SlaveDSI
Data Channel
IPC Link
GridFTP Server GridFTP Server
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Data Transfer Comparison
Control
Data
Control
Data
Control
Data
Control
Data
globus-url-copy RFT Service
RFT Client
SOAP Messages
Notifications(Optional)
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Replica Management in Grids
• Data intensive applications produce terabytes or petabytes of data– Hundreds of millions of data objects
• Replicate data at multiple locations for reasons of:– Fault tolerance
• Avoid single points of failure
– Performance• Avoid wide area data transfer latencies• Achieve load balancing
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
A Replica Location Service• A Replica Location Service (RLS) is a distributed
registry that records the locations of data copies and allows replica discovery– RLS maintains mappings between logical identifiers
and target names – Must perform and scale well: support hundreds of
millions of objects, hundreds of clients
• E.g., LIGO (Laser Interferometer Gravitational Wave Observatory) Project– RLS servers at 8 sites– Maintain associations between 3 million logical file
names & 30 million physical file locations
• RLS is one component of a Replica Management system– Other components include consistency services,
replica selection services, reliable data transfer, etc.
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Goals for OGSA-DAI• Aim to deliver application mechanisms that:
– Meet the data requirements of Grid applications • Functionality, performance and reliability• Reduce development cost of data centric Grid applications• Provide consistent interfaces to data resources
– Acceptable and supportable by database providers• Trustable, imposed demand is acceptable, etc.• Provide a standard framework that satisfies standard
requirements
• A base for developing higher-level services– Data federation– Distributed query processing– Data mining– Data visualisation
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Data Management Q & A
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Grid Monitoring Services• Overview• Index Service
– Aggregate the data• Trigger Service
– Notify when data changes• Information Providers
– Provide the data• WebMDS
– Client to visualize data
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
What Is Grid Monitoring?• A way to discover what services and
resources are available to use (Discovery)
• A way to understand the status/attributes of those services (Monitoring)
• A system to warn you when things fail
• Sharing of community data between sites using a standard interface for querying and notification.
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Why Grid Monitoring Hard?• Lack of central control
– Different local systems according to local policy
– Different interfaces and monitoring requirements
• Shared resources– Contention, variability
• Communication– Different sites implies different sys
admins, users, institutional policies
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
MDS4Monitoring and Discovery
System• Grid-level monitoring system used most often for resource selection– Aid user/agent to identify host(s) on which to run an
application
• Uses standard interfaces to provide publishing of data, discovery, and data access, including subscription/notification– WS-ResourceProperties, WS-BaseNotification, WS-
ServiceGroup
• Functions as an hourglass to provide a common interface to lower-level monitoring tools
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
GLUE Schema Attributes(cluster info,queue info, FS info)
Information Users :Schedulers, Portals, etc.
Cluster monitors(Ganglia, Hawkeye,Clumon, and Nagios soon)
Services(GRAM, RFT, RLS)
Queueing systems(PBS, LSF, Torque)
WS standard interfaces for subscription, registration, notification
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
MDS4 Components• Higher level services
– Index Service – a way to aggregate data– Trigger Service – a way to be notified of changes– Both built on common aggregator framework
• Information providers– Monitoring is a part of every WSRF service– Non-WS services can also be used
• Clients– WebMDS
• All of the tool are schema-agnostic, but interoperability needs a well-understood common language
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Sample Deployment
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
WebMDS User Interface• Web-based interface to WSRF resource
property information• User-friendly front-end to the Index Service• Uses standard resource property requests to
query resource property data• XSLT transforms to format and display them• Customized pages are simply done by using
HTML form options and creating your own XSLT transforms
• Sample page:– http://mds.globus.org:8080/webmds/
webmds?info=indexinfo&xsl=servicegroupxsl
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
WebMDS Service
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Information Services Q & A
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
GRAM
• Overview• Submitting a test job• Resource Specification Language
(RSL)• Data Staging• Multi-jobs
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
GRAM Overview
• Intended for jobs where arbitrary programs, state-ful monitoring, credential management, and file staging are important
• If the application is lightweight, with modest input/output, may be a better candidate for hosting directly as a WSRF service
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
GRAM Prerequisites
• A secure container• For staging jobs, access to an RFT
service and a GridFTP server– Note that even stderr/stdout are
considered staging, so RFT and GridFTP are used in all but the most basic jobs
• sudo for running as other accounts• Can be integrated with PBS, LSF,
Condor
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Submitting A Test Job
• globusrun-ws –submit –c /bin/true• echo $?• Will run locally. Specify a remote
host with –F• globusrun-ws –submit –F host2 –
c /bin/true• The return code will be the job’s
exit code if supported by the scheduler
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Data Staging
• GRAM allows jobs to stage-in and stage-out data
• To perform this task it uses RFT• RFT in turn uses GridFTP servers• Simplest stage-in/stage-out
example is stdout/stderr
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Streaming Results
• globusrun-ws –S –s –c /bin/date• -S is short for “-submit”• -s is short for –streaming
– The output will be sent back to the terminal, control will not return until the job is done
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Resource Specification Language
• For more complicated jobs, we’ll use RSL to specify the job
<job><executable>/bin/echo</executable><argument>this is an example_string
</argument><argument>Globus was here</argument><stdout>${GLOBUS_USER_HOME}/stdout</
stdout>
<stderr>${GLOBUS_USER_HOME}/stderr</stderr>
</job>
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Submitting Using XML
• Create the file containing the RSL• You may validate the RSL ahead of
time– globusrun-ws –validate –f
rslfile.xml
• If the file validates, submit using -submit
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
At Most Once Submission• You may specify a UUID with your job
submission• If you’re not sure the submission
worked, you may submit the job again with the same UUID
• If the job has already been submitted, the new submission will have no effect
• If you do not specify a UUID, one will be generated for you
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Staging Data
• GRAM’s RSL allows many fileStageIn/fileStageOut directives
• The transfers will be executed by RFT– May specify additional RFT options
using the RFTOptions tag
• There is no GASS cache staging option anymore
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Batch Submission
• Your client does not have to stay attached to the execution of the job
• -batch will disconnect from the job and output an EPR– You may redirect the EPR to a file
with –o
• Use the EPR file with –monitor or -status
• You may also kill the job using -kill
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Specifying Scheduler Options
• RSL lets you specify various scheduler options– what queue to submit to– which project to select for accounting– max CPU and wallclock time to spend– min/max memory required
• All defined online under the schema document for GRAM
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Multijobs
• You may specify more than one <job> element in a <multijob>
• At that point, you want to specify the <factoryEndpoint> in the RSL rather than the commandline
• Will be used by MPICH-G to support MPI jobs
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
Resource Management Q & A
December 8 & 9, 2005, Austin, TXSURA Cyberinfrastructure Workshop Series: Grid Technology: The Rough Guide
For more information
• The Globus Toolkit ™– http://www-unix.globus.org/toolkit/
• The Globus Toolkit ™– http://www-unix.globus.org/toolkit/
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