1. A Module Extension to OpenPBS: Principles, Implementation and Experience
Mike Becher and Wolfgang Rehm
Computing Center of the University, Chemnitz University of Technology
Department of Computer Science, Chemnitz University of Technology
Reporter： P . J . L
2007/12/05

2. Outline 1 Abstract 2 Introduction 3 Analysis of OpenPBS 4 Concept 5
Conclusions 5
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3. Abstract
If the application of OpenPBS is planned in an AFS environment (Andrew distributed file system)
Design of a modular extension of OpenPBS
Module-Implementation for the safe forwording and usability of an AFS-Token
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4. Introduction OpenPBS “ Portable Batch System ”
Manage access to nodes for a large group of different users in fair manner
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5. Introduction ( Cont. )
The idea to forward a password is rejected due to of two reasons
Forwarding a password might lead to a security problem
Independence from password changing is desired
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6. Analysis of OpenPBS Steps followed by a job requiring two nodes
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7. Analysis of OpenPBS ( Cont. )
Job creation by user
Create a job that requires two nodes
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8. Analysis of OpenPBS ( Cont. )
Job submission
Submits his job with qsub command
All checks are successfully passed → job is now in state ‘queued
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9. Analysis of OpenPBS ( Cont. )
Job scheduling
Batch server sends a message to the scheduler, pbs_sched
Debit balance and actual of batch environment it talks with pbs_mom, Machine Oriented Mini Daemons (MOM)
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10. Analysis of OpenPBS ( Cont. )
Job stage in
Batch server will transfer the job to a master MOM
This master MOM gets this job
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11. Analysis of OpenPBS ( Cont. )
Job execution
Master MOM also gets a list of sister MOM’s from the batch server
Will be ‘queued’ again . Only if it is flagged as ‘rerunable’
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12. Analysis of OpenPBS ( Cont. )
Interactive job
The pbs_mom opens a bidirectional connection to the waiting qsub command of the user to establish a console connection
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13. Concept AFS token extension AFS token forwarding and extension scheme
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14. Concept ( Cont. )
At batch server site AFS token should be stored like all other relevant job data
Batch-System should only know the data file name but not its size
At pbs_server site the AFS token lifetime should be monitored
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15. MOM must set the AFS token of a job
Concept ( Cont. )
AFS token extension
MOM must set the AFS token of a job
Before it tries to receive data at time of ‘ stage-in ’
Before it begins with the process of job execution
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16. This process should monitor AFS token lifetime at MOM site
Concept ( Cont. )
AFS token extension
This process should monitor AFS token lifetime at MOM site
It is done by the pbs_server process
The additional process at batch server site
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17. Conclusions
We successfully migrated from the existing system to the secure version of AFS token forwarding and extension module to solve our security problem with clear text token forwarding
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18. Thank You !