1 / 23

Condor DAGMan: Managing Job Dependencies with Condor

Condor DAGMan: Managing Job Dependencies with Condor. Condor DAGMan. What is DAGMan? What is it good for? How does it work? What’s next?. DAGMan. D irected A cyclic G raph Man ager

chance
Download Presentation

Condor DAGMan: Managing Job Dependencies with Condor

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Condor DAGMan:Managing Job Dependencies with Condor

  2. Condor DAGMan • What is DAGMan? • What is it good for? • How does it work? • What’s next? Condor DAGMan

  3. DAGMan • Directed Acyclic Graph Manager • DAGMan allows you to specify the dependencies between your Condor jobs, so it can manage them automatically for you. • (e.g., “Don’t run job “B” until job “A” has completed successfully.”) Condor DAGMan

  4. Typical Scenarios • Jobs whose output needs to be summarized or post-processed once they complete. • Jobs that need data to be generated or pre-processed before they can use it. • Jobs which require data to be staged to/from remote repositories before they start or after they finish. Condor DAGMan

  5. Job A Job B Job C Job D What is a DAG? • A DAG is the datastructure used by DAGMan to represent these dependencies. • Each job is a “node” in the DAG. • Each node can have any number of “parents” or “children” (or neither) – as long as there are no loops! Condor DAGMan

  6. An Example DAG • Jobs whose output needs to be summarized or post-processed once they complete: Job A Job B Job C Job D Condor DAGMan

  7. Another Example DAG • Jobs that need data to be generated or pre-processed before they can use it: Job A Job B Job C Job D Condor DAGMan

  8. Job A Job B Job C Job D Defining a DAG • A DAG is defined by a .dagfile., listing all its nodes and any dependencies: # diamond.dag Job A a.sub Job B b.sub Job C c.sub Job D d.sub Parent A Child B C Parent B C Child D Condor DAGMan

  9. Job A Job B Job C Job D Defining a DAG (cont’d) • Each node in the DAG will run a Condor job, specified by a Condor submit file: # diamond.dag Job A a.sub Job B b.sub Job C c.sub Job D d.sub Parent A Child B C Parent B C Child D Condor DAGMan

  10. Submitting a DAG • To start your DAG, just run condor_submit_dag with your .dag file, and Condor will start a personal DAGMan daemon & begin running your jobs: • % condor_submit_dag diamond.dag • The DAGMan daemon itself runs as a Condor job, so you don’t have to baby-sit it. Condor DAGMan

  11. Running a DAG • DAGMan acts as a “meta-scheduler”, managing the submission of your jobs to Condor based on the DAG dependencies. DAGMan A Condor Job Queue .dag File A B C D Condor DAGMan

  12. Running a DAG (cont’d) • DAGMan holds & submits jobs to the Condor queue at the appropriate times. DAGMan A Condor Job Queue B B C C D Condor DAGMan

  13. Running a DAG (cont’d) • In case of a job failure, DAGMan continues until it can no longer make progress, and then creates a “rescue” file with the current state of the DAG. DAGMan A Condor Job Queue Rescue File B X D Condor DAGMan

  14. Recovering a DAG • Once the failed job is ready to be re-run, the Rescue file can be used to restore the prior state of the DAG. DAGMan A Condor Job Queue Rescue File B C C D Condor DAGMan

  15. Recovering a DAG (cont’d) • Once that job completes, DAGMan will continue the DAG as if the failure never happened. DAGMan A Condor Job Queue B C D D Condor DAGMan

  16. Finishing a DAG • Once the DAG is complete, the DAGMan job itself is finished, and exits. DAGMan A Condor Job Queue B C D Condor DAGMan

  17. Additional Features • Provides some other handy features for job management… • nodes can have PRE & POST scripts • job submission can be “throttled” Condor DAGMan

  18. PRE & POST Scripts • Each node can have a PRE or POST script, executed as part of the node: # diamond.dag Job A a.sub Job B b.sub Job C c.sub Job D d.sub PARENT A CHILD B C PARENT B C CHILD D Script PRE B stage-in.sh Script POST B stage-out.sh Job A PRE Job B POST Job C Job D Condor DAGMan

  19. PRE & POST Scripts (cont’d) • Useful for staging a job’s data from remote repositories, and/or putting it back afterwards. • Ex: • PRE: Globus FTP the data from afar • Run the job • POST: Globus FTP the data back Condor DAGMan

  20. Submit Throttling • DAGMan can limit the maximum number of jobs it will submit to Condor at once: • condor_submit_dag -maxjobs N • Useful for managing resource limitations (e.g., storage). • Ex: 1000 jobs, each of which require 1 GB of disk space, and you have 100 GB of disk. Condor DAGMan

  21. Summary • DAGMAN: • manages dependencies, holding & running jobs only at the appropriate times • monitors job progress • is fault-tolerant • is recoverable in case of job failure • provides some additional features to Condor • currently DAGMan itself can only run on Unix, but its jobs can run anywhere Condor DAGMan

  22. Future Work • More sophisticated management of remote data transfer & staging to maximize CPU throughput. • Keep the pipeline full! I.e., intelligently manage disk & network to always have remote data ready where a CPU becomes available. • Possible integration with Kangaroo, etc. • Better integration with Condor tools • condor_q, etc. displaying DAG information Condor DAGMan

  23. Conclusion • Interested in seeing more? • Come to the DAGMan demo • Wednesday 9am - noon • Room 3393, Computer Sciences (1210 W. Dayton St.) • Email me: • <pfc@cs.wisc.edu> • Try it: • http://www.cs.wisc.edu/condor Condor DAGMan

More Related