March 2024 - slurm-users - lists.schedmd.com

job_container/tmpfs and srun.
by Phill Harvey-Smith 17 Jan '25

17 Jan '25

Hi all, On our setup we are using job_container/tmpfs to give each job it's own temp space. Since our compute nodes have reasonably sized disks for tasks that do a lot of disk I/O on user's data we have asked users to copy their data to the local disk at the beginning of the task and (if needed) copy it back at the end. This saves lots of NFS thrashing slowing down both the task and the NFS servers. However some of our users are having problems with this, their initial sbatch script will create a temp directory in their private /tmp copy their data to it and then try to srun a program. The srun will fall over as it doesn't seem to have have access to the copied data. I suspect this is because the srun task is getting it's own private /tmp. So my question is, is there a way to have the srun task inherit the /tmp of the initial sbatch? I'll include a sample of the script our user is using below. If any further information is required please feel free to ask. Cheers. Phill. #!/usr/bin/bash #SBATCH --nodes 1 #SBATCH --ntasks-per-node=1 #SBATCH --cpus-per-task=1 #SBATCH --time=00:00:10 #SBATCH --mem-per-cpu=3999 #SBATCH --output=script_out.log #SBATCH --error=script_error.log # The above options puts the STDOUT and STDERR of sbatch in # log files prefixed with 'script_'. # Create a randomly-named directory under /tmp jobtmpdir=$(mktemp -d) # Register a function to try and cleanup in case of job failure cleanup_handler() { echo "Cleaning up ${jobtmpdir}" rm -rf ${jobtmpdir} } trap 'cleanup_handler' SIGTERM EXIT # Change working directory to this directory cd ${jobtmpdir} # Copy the executable and input files from # where the job was submitted to the temporary directory. cp ${SLURM_SUBMIT_DIR}/a.out . cp ${SLURM_SUBMIT_DIR}/input.txt . # Run the executable, handling the collection of stdout # and stderr ourselves by redirecting to file srun ./a.out 2> task_error.log > task_out.log # Copy output data back to the submit directory. cp output.txt ${SLURM_SUBMIT_DIR} cp task_out.log ${SLURM_SUBMIT_DIR} cp task_error.log ${SLURM_SUBMIT_DIR} # Cleanup cd ${SLURM_SUBMIT_DIR} cleanup_handler

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AllowAccounts partition setting
by Marko Markoc 17 Oct '24

17 Oct '24

Hi All, At one point, when we were running slurm 22, we set up a few new partitions with `AllowAccounts` setting enabled. We limit access to these partitions only to a few accounts. We manually create these accounts and users using the `sacctmgr` command. At that time, everything was working. Only users in these accounts were able to run jobs in that partition. Few months ago we upgraded slurm to 23.02.7 but just a couple of days ago we noticed that anyone could submit jobs to these partitions. In addition to that, you can provide any value to the `--account` directive and slurm will accept and record it in the job accounting database. In our initial testing, you could only provide `--account` value that has been previously created. I'm still looking into this but I wanted to check if there was any change in version 23 that could have impacted this? I don't remember seeing anything in release notes. Thanks, Marko

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Can't schedule on cloud node: State=IDLE+CLOUD+POWERED_DOWN+NOT_RESPONDING
by Xaver Stiensmeier 20 Sep '24

20 Sep '24

Dear slurm-user list, I have a cloud node that is powered up and down on demand. Rarely it can happen that slurm's resumeTimeout is reached and the node is therefore powered down. We have set ReturnToService=2 in order to avoid the node being marked down, because the instance behind that node is created on demand and therefore after a failure nothing stops the system to start the node again as it is a different instance. I thought this would be enough, but apparently the node is still marked with "NOT_RESPONDING" which leads to slurm not trying to schedule on it. After a while NOT_RESPONDING is removed, but I would like to move it directly from within my fail script if possible so that the node can return to service immediately and not be blocked by "NOT_RESPONDING". Best regards, Xaver

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Interfaces of topology/tree and Topology Awareness
by nico.derl＠tutanota.com 15 Apr '24

15 Apr '24

Hello everyone, I'm trying to improve topology awareness in a local Slurm-managed HPC system. It's using the default hierarchical 3-level topology with the tree-plugin. It however does not always confine jobs to the most tightly packed group of nodes, seems to over-provision switches for smaller jobs, and gets slow or overwhelmed with jobs that have a high node count. I'd like to implement something more literally aligned with best-fit, but I'm having trouble understanding the relevant interfaces to hook into the topology model of Slurm. I would like a high-level explanation of how the tree- and common topology components work, how they integrate into the higher scheduling logic and what the internal topology model looks like. Or some pointers to relevant docs discussing this. I have read the topology guide and its dev-doc, which does note some of the caveats I mentioned. It however only talks about providing a set of weights to the upper logic levels in the form of a node ranking. I can't see how this ranking resembles the topology and how it's being used. From looking at the signatures and C-code I can tell this much: topology-tree consumes the topology.conf and generates a ranking of some kind that is passed to topology-common. topology-common consumes a ranking and uses its own gres-sched to figure out what nodes can fit a job (possibly pulling info from the gres-select-plugin to determine node capabilities). It's then supposed to apply a best-fit algorithm to efficiently fill up vacant cluster-capacity, but I can't manage to follow this part in the code as everything crumbles into separate files that I can't link correctly in my head. Thanks in advance. referenced docs: <https://slurm.schedmd.com/topology.html> <https://hpc.rz.rptu.de/documentation/topology_plugin.html> <https://github.com/SchedMD/slurm/tree/master/src/plugins/topology/common>

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PMIxDirectConn Setting
by efweber＠uwe.nsa.gov 28 Mar '24

28 Mar '24

Hi, The documentation for mpi.conf says: PMIxDirectConn={true|false} Disable direct launching of tasks. Default is "true". I'm finding this a bit confusing. Does true really mean that Direct Connection is disabled? I would have thought true meant enabled. Thanks

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Incorrect hyperthreading with Slurm 23.11
by Guillaume COCHARD 28 Mar '24

28 Mar '24

Hello, We have upgraded our cluster to Slurm 23.11.1 then, a few weeks later, to 23.11.4. Since then, Slurm doesn't detect hyperthreaded CPUs. We have downgraded our test cluster, the issue is not present with Slurm 22.05 (we had skipped Slurm 23.02). For example, we are working with this node: $ slurmd -C NodeName=node03 CPUs=40 Boards=1 SocketsPerBoard=2 CoresPerSocket=10 ThreadsPerCore=2 RealMemory=128215 It is defined like this in slurm.conf: SelectTypeParameters=CR_CPU_Memory TaskPlugin=task/cgroup,task/affinity NodeName=node03 CPUs=40 RealMemory=150000 Feature=htc MemSpecLimit=5000 NodeSet=htc Feature=htc PartitionName=htc Default=YES MinNodes=0 MaxNodes=1 Nodes=htc DefMemPerCPU=1000 State=UP LLN=Yes MaxMemPerNode=142000 So no oversubscribing, 20 cores and 40 CPUs thanks to hyperthreading. Until the updgrade, Slurm was allocating those 40 CPUs: when launching 40 jobs of 1 CPU, each of those job would use one 1 CPU. This is the expected behavior. Since the upgrade, we can still launch those 40 jobs, but only the first half of the CPUs will be used (CPUs 0 to 19 according to htop). Each of those CPUs is used by 2 jobs, and the second half of the CPUs (#20 to 39) stay completely idle. When launching 40 stress processes directly in the node without using Slurm all the CPUs are used. When allocating a specific CPU with srun, it works until CPU #19 and then an error occurs even if the allocation includes all the CPUs of the node: #SBATCH --ntasks=1 #SBATCH --cpus-per-task=40 # Works for 0 to 19 srun --cpu-bind=v,map_cpu:19 stress.py # Doesn't work (20 to 39) srun --cpu-bind=v,map_cpu:20 stress.py # Output: srun: error: CPU binding outside of job step allocation, allocated CPUs are: 0x00000FFFFF. srun: error: Task launch for StepId=57194.0 failed on node node03: Unable to satisfy cpu bind request srun: error: Application launch failed: Unable to satisfy cpu bind request srun: Job step aborted This behaviour concerns all our nodes, some of which have been restarted recently and others have not. This causes the jobs to be frequently interrupted, augmenting the difference between the system real time and user+system times and making the jobs slower. We have been peering the documentation but, from what we understand, our configuration seems correct. In particular, as advised by the documentation[1], we don't set up ThreadsPerCore in slurm.conf. Are we missing something, or is there a regression or a change in Slurm configuration since the version 23.11? Thank you, Guillaume [1] : https://slurm.schedmd.com/slurm.conf.html#OPT_ThreadsPerCore

2 1

FairShare priority questions
by Long, Daniel S. 27 Mar '24

27 Mar '24

Hi, I’m trying to set up multifactor priority on our cluster and am having some trouble getting it to behave the way I’d like. My main issues seem to revolve around FairShare. We have multiple projects on our cluster and multiple users in those projects (and some users are in multiple projects, of course). I would like the FairShare to be based only on the project associated with the job; if user A and user B both submit jobs on project C, the FairShare should be identical. However, it looks like the FairShare is based on both the project and the user. Is there a way to get the behavior I’m looking for? Thanks for any help you can provide.

3 2

Slurm releases move to a six-month cycle
by Tim Wickberg 26 Mar '24

26 Mar '24

Slurm major releases are moving to a six month release cycle. This change starts with the upcoming Slurm 24.05 release this May. Slurm 24.11 will follow in November 2024. Major releases then continue every May and November in 2025 and beyond. There are two main goals of this change: - Faster delivery of newer features and functionality for customers. - "Predictable" release timing, especially for those sites that would prefer to upgrade during an annual system maintenance window. SchedMD will be adjusting our handling of backwards-compatibility within Slurm itself, and how SchedMD's support services will handle older releases. For the 24.05 release, Slurm will still only support upgrading from (and mixed-version operations with) the prior two releases (23.11, 23.02). Starting with 24.11, Slurm will start supporting upgrades from the prior three releases (24.05, 23.11, 23.02). SchedMD's Slurm Support has been built around an 18-month cycle. This 18-month cycle has traditionally covered the current stable release, plus one prior major releases. With the increase in release frequency this support window will now cover to the current stable release, plus two prior major releases. The blog post version of this announcement includes a table that outlines the updated support lifecycle: https://www.schedmd.com/slurm-releases-move-to-a-six-month-cycle/ - Tim -- Tim Wickberg Chief Technology Officer, SchedMD LLC Commercial Slurm Development and Support

1 0

controller backup slurmctld error while takeover
by Miriam Olmi 26 Mar '24

26 Mar '24

Dear all, I am having trouble finalizing the configuration of the backup controller for my slurm cluster. In principle, if no job is running everything seems fine: both the slurmctld services on the primary and the backup controller are running and if I stop the service on the primary controller after 10s more or less (SlurmctldTimeout = 10 sec) the backup controller takes over. Also, if I run the sinfo or squeue command during the 10s of inactivity, the shell stay pending but it recover perfectly after the time needed by the backup controller to take control and it works the same when the primary controller is back. Unfortunately, if I try to do the same test while a job is running there are two different behaviors depending on the initial scenario. 1st scenario: Both the primary and backup controller are fine. I launch a batch script and I verify the script is running with sinfo and squeue. While the script is still running I stop the service on the primary controller with success but at this point everything gets crazy: on the backup controller in the slurmctld service log I find the following errors: slurmctld: error: Invalid RPC received REQUEST_JOB_INFO while in standby mode slurmctld: error: Invalid RPC received REQUEST_PARTITION_INFO while in standby mode slurmctld: error: Invalid RPC received REQUEST_JOB_INFO while in standby mode slurmctld: error: Invalid RPC received REQUEST_PARTITION_INFO while in standby mode slurmctld: error: slurm_accept_msg_conn poll: Bad address slurmctld: error: slurm_accept_msg_conn poll: Bad address and the commands sinfo and squeue are Unable to contact slurm controller (connect failure). 2nd scenario: the primary controller is stopped and I launch a batch job while the backup controller is the only one working. While the job is running, I restart the slurmctld service on the primary controller. In this case the primary controller takes over immediately: everything is smooth and safe and the sinfo and squeue commands continue to work perfectly. What might be the problem? Many thanks in advance! Miriam

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cgroups_exporter for slurm on rhel9 (cgroups-v2)
by Saluja, Prabhjyot 25 Mar '24

25 Mar '24

Hi All, We are currently trying to set up cgroup_exporter <https://github.com/treydock/cgroup_exporter> for slurm. It's been working smoothly with cgroups.v1 and slurm-22.05.7. However, we're facing some challenges with RHEL-9, slurm-23.11.1 and cgroups.v2. The cgroup_exporter isn't capturing the slurm cgroup job information. I'm reaching out to see if any other sites have managed to make this work. If you're using a different exporter that's working for your site, could you please let us know? Thanks! Regards, Singh

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