1. Condor Birdbath Web Service interface to Condor
Clovis Chapman, Charaka Goonatilake, Wolfgang Emmerich,
Matthew Farrellee, Todd Tannenbaum, Miron Livny,
Mark Calleja and Martin Dove

2. Condor Overview
Jobs
(command-line)
Submission
Machine
(Schedules Jobs)
Central
manager
Execution machines
UCL 940 machines – CamGrid
High-throughput computing resource manager and job scheduler. Allows idle computing resources to be exploited , etc. …
UCL Condor Pool: ~ 940 Windows Terminal Servers spread over 30 student clusters (3 years running)
CamGrid: ~140 Linux machines spread over 8 pools brought together through flocking

3. Motivations
Facilitate the development of third-party tools and applications capable of interacting with Condor remotely.
E.g. Build higher-level application specific scheduler that submits jobs to one or more Condor pools according to application semantics
These can be built using a wide range of languages/SOAP packages – Birdbath tested on:
Java (Apache Axis, XSUL)
Python (ZSI)
C# (.Net)
C/C++ (gSOAP)
Can also use Web Service based workflow modelling languages such as BPEL (Business Process Execution Language)
Build Web Service support within the Condor architecture itself
i.e. Rather than rely on external “wrappers” (e.g. Globus Toolkit)
Expose a wide range of high-throughput computing services based on Condor capabilities (e.g. workload/queue management, scheduling, checkpointing, job migration, etc.)
Rather than wrap up a condor pool – provide different services
Mention embedding grid considerations within the condor architecture
Musnt affect features that made it popular 3

4. The big picture 4 BPEL Site D: Bath Condor-G Client SOAP SOAP Schedd
Globus/gridSAM
Client
BPEL
SOAP
SOAP
Schedd
Schedd
Schedd
flocking
Site A:
CamGrid
Site B:
UCL
Site C: RI 4

5. Why SOAP? Alternatives 5 Building wrappers around command line tools
Globus Toolkit 3
Good when interacting with different types of resource managers. Otherwise Birdbath has a richer, more scalable and streamlined interface which is more suited to Condor.
Condor’s GAHP protocol: ASCII stream-based protocol.
Built within Condor itself. Simple Condor specific protocol for remote submission
No Type Safety / interface declaration / session management.
DRMAA API: built-in support
API for the submission and control of jobs to one or more Distributed Resource Management Systems defined by the GGF.
Allows access to Condor through Local procedure calls
C binding only / Weak fault tolerance 5

6. Submission machine(s)
Condor Architecture overview
Central manager
Negotiator
Collector
Job ClassAd
Resource
classAd
Submission machine(s)
Execution machine(s)
Startd
Schedd
Starter
Shadow 6

7. Condor Architecture overview
ClassAds
Universe = Vanilla
Requirements = (OpSys == “WINNT50”) \
&& (Arch == “INTEL”) \
&& (Memory > 256)
Executable = cpusoak.exe
Input = input.txt
Output = output.txt
TransferFiles = IF_NEEDED
Arch = "INTEL"
OpSys = "WINNT50"
State = "Unclaimed"
Activity = "Idle"
LoadAvg =
Memory = 256
Cpus = 1 7

8. Condor SOAP extensions
Remote Client
Obtain pool characteristics (resource ClassAds)
Submit Job (send job ClassAd)
Monitor Job (Obtain Job ClassAds)
Get/Send file
Cancel/hold/release job
Execution
machine
Execution
machine
Submission
machine(s)
Central manager
Schedd
Collector
Negotiator
Execution
machine
Shadow
Execution
machine 8

9. Clients for the Condor Web Services
Custom Client
holdJob()
Submission
machine(s)
SOAP library
Schedd
All libraries can be generated (automatically) based on interface description provided by us (WSDL)
The WSDL interface defines which operations can be called and their parameters (e.g. queryAds(Constraint))
Alternatively use a Web Service based orchestration language like BPEL (Business Process Execution Language) 9

10. Quick application example: Collector Query
Using Axis API.
Generate stubs from WSDL file using WSDL2Java
e.g. Obtain information about all resources that have over 512Mb RAM
locator = new CondorLocator();
collector = locator.getCollector(new URL(“
ads = collector.QueryStartdAds(“Memory>512”); 10

11. Quick Application example: Job Submission
Transaction based process
New Transaction()
New Job ID ()
Send Files ({input files, binaries})
Send Job Description(ClassAd)
Commit Transaction()
File transfer is in segments (specified by users) – using simple protocol
Two Phase Commit for increased robustness
Can also submit DAG-Man jobs 11

12. Available in Condor 6.7.5 dev releases
Simply add the following to your configuration file:
ENABLE_SOAP = TRUE
ENABLE_WEB_SERVER = TRUE
WEB_ROOT_DIR = $RELEASE_DIR/lib/webservice 12

13. OMII Collaboration: GridSAM plugin
Web Service based job submission service
Uses JSDL (Job Submission Description Language) for standardized job submission to a wide range of resource managers
Job Manager
SGE
connector
Condor
LSF
Network
JSDL
SOAP
Client
GridSAM
Web Service
<?xml version="1.0" encoding="UTF-8"?>
<JobDefinition xmlns="
<JobDescription>
<Application>
<Executable>/bin/echo</Executable>
<Argument>hello world</Argument>
</Application>
</JobDescription>
</JobDefinition>
submit

14. Condor WS plug-in for GridSAM
Client
Advantages:
Independent deployment of GridSAM
Submission to multiple schedulers – load balancing
Increased robustness and fault handling
Access to a wider range of Condor functionality – Condor-G, etc.
Network
GridSAM
Web Service
Job Manager
SGE
connector
WS-Condor
connector
LSF
connector
Network
Condor Pool UCL
Schedd 14

15. Condor WS plug-in for GridSAM
Client
Advantages:
Independent deployment of GridSAM
Submission to multiple schedulers – load balancing
Increased robustness and fault handling
Access to a wider range of Condor functionality – Condor-G, etc.
Network
GridSAM
Web Service
Job Manager
SGE
connector
WS-Condor
connector
LSF
connector
Network
UCL Pool
CamGrid RI
Schedd
Schedd
Schedd 15

16. BPEL orchestration of scientific workflows16

17. Still to be done Security (SSL for now)
Certificate based security
Using mappings to local accounts
Take advantage of additional capabilities of WSRF and WS-notification (scheduler instances, etc.)
Exposing more components (e.g. shadow for remote checkpointing and retrieval of partial output files) 17

18. Download Condor SOAP interface available from version 6.7.5:
Condor-WS GridSAM soon to be provided with GridSAM: 18