diff --git a/README.md b/README.md index 88feb78..7e9a9ec 100644 --- a/README.md +++ b/README.md @@ -8,24 +8,90 @@ ospool: In this lesson, we'll learn how to troubleshoot jobs that never start or fail in unexpected ways. # Troubleshooting techniques +We will look into 4 criteria. The criteria are listed below ## Diagnostics with condor_q + - [Job is held](#job-is-held) + - [Job completed but was unsuccessful](#job-completed-but-was-unsuccessful) + - [Job does not start](#job-does-not-start) + - [Job is running longer than expected](#job-is-running-longer-than-expected) -The `condor_q` command shows the status of the jobs and it can be used -to diagnose why jobs are not running. Using the `-better-analyze` flag -with `condor_q` can show you detailed information about why a job isn't -starting on a specific pool. Since OSG Connect sends jobs to many places, we also need to -specify a pool name with the `-pool` flag. +## Job is held +HTCondor puts your jobs on hold when something goes wrong in the process of managing your jobs. HTCondor provides a ``Hold Reason`` that explains what went wrong. To see what went wrong you can use the command `condor_q -hold`. A typical hold message may look like the following -Unless you know a specific pool you would like to query, checking the `flock.opensciencegrid.org` pool is usually a good place to start. + $ condor_q -hold + ap40.uw.osg-htc.org : <128.105.68.62:9618?... @ 08/01/24 15:01:50 + ID OWNER HELD_SINCE HOLD_REASON + 130.0 alice 8/1 14:56 Transfer output files failure at ⋯ - $ condor_q -better-analyze JOB-ID -pool POOL-NAME +In this particular case, the message indicates that HTCondor cannot transfer back output files, likely because they were never created. This hold condition can be triggered if a user has this option in their HTCondor submit file: + + transfer_output_files = outputfile + +However, when the job executed, it went into the Held state. To learn more, `condor_q -hold JOB-ID` can be used. An example from this scenario is shown below: + + $ condor_q -hold JOB-ID + + Transfer output files failure at access point… while receiving files from the execution point. Details: Error from ….execute point … failed to send file(s) at apxx; failed to read from file /path: (errno 2) No such file or directory + +The reason why the file transfer failed is because `outputfile` was never created on the worker node. Remember that at the beginning we said that the user specifically requested `transfer_outputfiles = outputfile`! HTCondor could not complete this request, and so the job went into the Held state instead of finishing normally. + +It's quite possible that the error was simply transient, and if we retry, the job will succeed. We can re-queue a job that is in Held state by using `condor_release`: + + condor_release JOB-ID + +### Common scenarios for job going on hold + +Some of the common scenarios and example hold mesaages where the job goes on hold are described below + +For these cases, sometimes it is better to just remove the jobs, fix the issues and then resubmit them. In some cases (e.g. excessive memory usage) using [condor_qedit](https://htcondor.readthedocs.io/en/latest/man-pages/condor_qedit.html) to fix the issue and releasing them might be convenient. Whenever in doubt please reach out to our [support](https://portal.osg-htc.org/documentation/support_and_training/support/getting-help-from-RCFs/) team. + +## Job completed but was unsuccessful +Under this case two things will be considered. First, your job has run but the code did not execute correctly or in the expected manner. Second, your job ran but it did not produce/transfer the desired output files. + +For these scenarios looking at the `error` and `log` files will provide more information about your job. In addition, having various `ls` or `echo` statements that shows the contents of the working directory and the code's progression are helpful in diagnosing the actual issue. An example is shown here: + + echo "Here are the files at the start of the job:" + ls -R + echo "Executing main command..." + my_command #Part of the original code + echo "... finished. Here are the files at the end of the job:" + ls -R + +While using the above commands, looking at the `output` file will provide the status of your code. In addition, for your commands if enabling debugging or verbose logging is an option then do those. Moreover, [condor_chirp](https://www.google.com/url?q=https://htcondor.readthedocs.io/en/latest/man-pages/condor_chirp.html&sa=D&source=editors&ust=1740162417565289&usg=AOvVaw1HJ8p454psoN6alPpujatn) can be a very useful tool in this regard as it sends information directly back to the Access Point. For example, the following will add a statement to your .log file: + command1 + condor_chirp ulog "Finished executing command1" + command2 +## Job does not start + +Matchmaking cycle (the process of finding an execution point to run the submitted jobs in queue) can take more than 5 minutes to complete and it can be longer if the server is busy. In addition, the more/more-specific resources are requested, typically the longer is the wait. For example if you are submitting a lot of GPU jobs, there may be fewer `GPUs` (than other resources) to run your jobs. This type of issue can be diagnosed using the `-better-analyze` flag +with `condor_q` to see the detailed information about why a job isn't +starting. + + $ condor_q -better-analyze JOB-ID Let's do an example. First we'll need to login as usual, and then load the tutorial *error101*. - $ ssh username@login.osgconnect.net + $ ssh username@apxx... - $ tutorial error101 + $ git clone https://github.com/OSGConnect/tutorial-error101.git $ cd tutorial-error101 $ condor_submit error101_job.submit @@ -34,10 +100,9 @@ We'll check the job status the normal way: condor_q username For some reason, our job is still idle. Why? Try using `condor_q --better-analyze` to find out. Remember that you will also need to -specify a pool name. In this case we'll use `flock.opensciencegrid.org`: +-better-analyze` to find out. - $ condor_q -better-analyze JOB-ID -pool flock.opensciencegrid.org + $ condor_q -better-analyze JOB-ID # Produces a long ouput. # The following lines are part of the output regarding the job requirements. @@ -53,7 +118,7 @@ specify a pool name. In this case we'll use `flock.opensciencegrid.org`: [5] 0 TARGET.Memory >= RequestMemory [8] 10674 TARGET.HasFileTransfer -By looking through the match conditions, we see that many nodes match our requests for the Linux operating system and the x86_64 architecture, but none of them match our requirement for 51200 MB of memory. +By looking through the match conditions, we see that many nodes match our requests for the Linux operating system and the x86_64 architecture, but none of them match our requirement for memory. Let's look at our submit script and see if we can find the source of this error: @@ -87,39 +152,26 @@ Alternatively, you can edit the resource requirements of the idle job in queue: condor_qedit JOB_ID RequestMemory 2048 - -## Held jobs and condor_release - -Occasionally, a job can fail in various ways and go into "Held" -state. Held state means that the job has encountered some error, and -cannot run. This doesn't necessarily mean that your job has failed, but, -for whatever reason, Condor cannot fulfill your request(s). - -In this particular case, a user had this in his or her Condor submit file: - - transfer_output_files = outputfile - -However, when the job executed, it went into Held state: - - $ condor_q -analyze 372993.0 - -- Submitter: login01.osgconnect.net : <192.170.227.195:56174> : login01.osgconnect.net - --- - 372993.000: Request is held. - Hold reason: Error from glidein_9371@compute-6-28.tier2: STARTER at 10.3.11.39 failed to send file(s) to <192.170.227.195:40485>: error reading from /wntmp/condor/compute-6-28/execute/dir_9368/glide_J6I1HT/execute/dir_16393/outputfile: (errno 2) No such file or directory; SHADOW failed to receive file(s) from <192.84.86.100:50805> - -Let's break down this error message piece by piece: - - Hold reason: Error from glidein_9371@compute-6-28.tier2: STARTER at 10.3.11.39 failed to send file(s) to <192.170.227.195:40485> - -This part is quite cryptic, but it simply means that the worker node -where your job executed (glidein_9371@compute-6-28.tier2 or 10.3.11.39) -tried to transfer a file to the OSG Connect login node (192.170.227.195) -but did not succeed. The next part explains why: - - error reading from /wntmp/condor/compute-6-28/execute/dir_9368/glide_J6I1HT/execute/dir_16393/outputfile: (errno 2) No such file or directory - -This bit has the full path of the file that Condor tried to transfer back to `login.osgconnect.net`. The reason why the file transfer failed is because `outputfile` was never created on the worker node. Remember that at the beginning we said that the user specifically requested `transfer_outputfiles = outputfile`! Condor could not complete this request, and so the job went into Held state instead of finishing normally. - -It's quite possible that the error was simply transient, and if we retry, the job will succeed. We can re-queue a job that is in Held state by using `condor_release`: - - condor_release JOB-ID +## Job is running longer than expected + +To troubleshoot this issue we recommend checking your .log files and see if +