April 2025 - slurm-users - lists.schedmd.com

Job running slower when using Slurm
by Jeffrey Layton 23 Apr '25

23 Apr '25

Good morning, I'm running an NPB test, bt.C that is OpenMP and built using NV HPC SDK (version 25.1). I run it on a compute node by ssh-ing to the node. It runs in about 19.6 seconds. Then I run the code using a simple job: Command to submit job: sbatch --nodes=1 run-npb-omp The script run-npb-omp is the following: #!/bin/bash cd /home/.../NPB3.4-OMP/bin ./bt.C.x When I use Slurm, the job takes 482 seconds. Nothing really appears in the logs. It doesn't do any IO. No data is copied anywhere. I'm king of at a loss to figure out why. Any suggestions of where to look? Thanks! Jeff

2 5

Strange output of sshare
by frsc＠adm.ku.dk 23 Apr '25

23 Apr '25

Hi all, I'm trying to clean up and reconfigure fair share on a slurm 20.11.9 production cluster after some trial and error before I started looking into it. I don't know the full story and need to pick up here. Fair share is enabled with default settings and not customised. It looks a bit like it was enabled by accident and relevant options are undefined/at default. As a first step I would like to understand the current state. Executing sshare includes output like this (output shortened but complete for the two relevant accounts): Account User Partition RawShares NormShares RawUsage EffectvUsage FairShare -------- ---------- ------------ ---------- ----------- ----------- ------------- ---------- root 0.000000 1002501 1.000000 .root root 1 0.083333 0 0.000000 1.000000 .A1 1 0.083333 0 0.000000 ..A1 U1 P1 1 0.166667 0 0.000000 0.873684 ..A1 U2 P1 1 0.166667 0 0.000000 0.873684 ..A1 U3 P1 1 0.166667 0 0.000000 0.873684 ..A1 U3 P2 1 0.166667 0 0.000000 0.873684 ..A1 U4 P3 1 0.166667 0 0.000000 0.873684 ..A1 U4 P1 1 0.166667 0 1.000000 0.821053 <== What is going on here?? .A2 1 0.083333 0 0.000000 ..A2 U5 P2 1 0.142857 0 0.000000 1.000000 ..A2 U5 P1 1 0.142857 0 0.000000 1.000000 ..A2 U6 P4 1 0.142857 0 0.000000 1.000000 ..A2 U6 P1 1 0.142857 0 0.000000 1.000000 ..A2 U6 P2 1 0.142857 0 0.000000 1.000000 ..A2 U7 P1 1 0.142857 0 0.000000 1.000000 ..A2 U7 P2 1 0.142857 0 0.000000 1.000000 User U4 is not a member of any other account. I understand everything about this output except the line I marked. Both accounts A1 and A2 have zero usage, yet, for user U4 on partition P1 we have effective usage 1.0, screwing the fair share factors up for everyone in this account. As far as I can tell, both accounts should look identical with a fair share factor of 1 for every user. I'm grateful for any pointer for what to look for. Best regards, Frank

2 1

Setting QoS with slurm 24.05.7
by Patrick Begou 22 Apr '25

22 Apr '25

Hi all, I'm trying to setup a QoS on a small 5 nodes cluster running slurm 24.05.7. My goal is to limit the resources on a (time x number of cores) strategy to avoid one large job requesting all the resources for too long time. I've read from https://slurm.schedmd.com/qos.html and some discussion but my setup is still not working. I think I need to set these informations: MaxCPUsPerJob=172800 MaxWallDurationPerJob=48:00:00 Flags=DenyOnLimit,OverPartQOS for: 12h max for 240 cores => (12*240*60=172800mn) no job can exceed 2 days do not accept jobs out of these limits. What I've done: 1) create the QoS: sudo sacctmgr add qos workflowlimit \ MaxWallDurationPerJob=48:00:00 \ MaxCPUsPerJob=172800 \ Flags=DenyOnLimit,OverPartQOS 2) Check sacctmgr show qos Name=workflowlimit format=Name%16,MaxTRES,MaxWall Name MaxTRES MaxWall ---------------- ------------- ----------- workflowlimit cpu=172800 2-00:00:00 3) Set the QoS for the account "most" which is the default account for the users: sudo sacctmgr modify account name=most set qos=workflowlimit 4) Check $ sacctmgr show assoc format=account,cluster,user,qos Account Cluster User QOS ---------- ---------- ---------- -------------------- root osorno normal root osorno root normal legi osorno normal most osorno workflowlimit most osorno begou workflowlimit 5) Modifiy slurm.conf with: AccountingStorageEnforce=limits,qos and propagate on the 5 nodes and the front end (done via Ansible) 6) Check clush -b -w osorno-fe,osorno,osorno-0-[0-4] 'grep AccountingStorageEnforce /etc/slurm/slurm.conf' --------------- osorno,osorno-0-[0-4],osorno-fe (7) --------------- AccountingStorageEnforce=limits,qos 7) restart slurmd on all the compute nodes and slurmctld + slurmdbd on the management node. But I can still request 400 cores for 24 hours: [begou@osorno ~]$ srun -n 400 -t 24:0:0 --pty bash bash-5.1$ squeue JOBID PARTITION NAME USER ST TIME START_TIME TIME_LIMIT CPUS NODELIST(REASON) 147 genoa bash begou R 0:03 2025-04-18T16:52:11 1-00:00:00 400 osorno-0-[0-4] So I must have missed something ? My partition (I've only one) in slurm.conf is: PartitionName=genoa State=UP Default=YES MaxTime=48:00:00 DefaultTime=24:00:00 Shared=YES OverSubscribe=NO Nodes=osorno-0-[0-4] Thanks Patrick

2 3

Slurm webhooks
by Davide DelVento 22 Apr '25

22 Apr '25

Happy Monday everybody, I've gotten a request to have Slurm notify users for the typical email things (job started, completed, failed, etc) with a REST API instead of email. This would allow notifications in MS Teams, Slack, or log stuff in some internal websites and things like that. As far as I can tell, Slurm does not support that, for example there was somebody who was looking for that on Galaxy and did not find a solution: https://help.galaxyproject.org/t/web-hook-post-to-external-url-when-job-beg… Is that indeed the case, as searching the web indicates? If Slurm does not support this, is there a workaround? For example, I'm thinking of installing a local SMTP server, or an alternative/dummy mailx program which instead of relaying emails as requested would post an encrypted web url thing using the information from the email. I am sure I could actually write such a software myself, but I don't have enough time to dedicate to the design, maintenance and debugging of such, so I am looking for something decent already in existence. A cursory web search did not find anything suitable, but perhaps I did not look in the appropriate places, because my gut feeling is that somebody must have already had such an itch to scratch! Any other ideas about alternative ways to accomplish this? Thanks

3 2

problem with slurmd dynamic mode with slurmctld in docker
by stef53864 22 Apr '25

22 Apr '25

hi everybody, i try to user dynamic mode with configless mode with slurm 24.11.3 and upgrade to 24.11.4 with slurmd and i found a problem. slurmctld is a container with docker, and my node is outside the container network . slurmctld register my ip with a function getpeeraddr on the slurmctld socket. but my ip connected to the socket come from the docker nat/bridge so slurmctld register my ip bridged ( not my real ip ) that is to say the docker gateway (172.20.0.1) *scontrol show node* *-------------------------* *NodeName=ltlsbubble1 Arch=x86_64 CoresPerSocket=4..NodeAddr=172.20.0.1 NodeHostName=ltlsbubble1 Version=24.11.4* so the node go down after the "not pinging it" timeout i try to update the config *scontrol uupdate NodeName=ltlsbubble1* *NodeAddr=xx.xx.xx.xx* but a the first *scontrol reconfigure * it comes back to : *NodeAddr=172.20.0.1* in normal mode ------------------- *scontrol show nodeNodeName=ltlsbubble1 Arch=x86_64 CoresPerSocket=4..NodeAddr=ltlsbubble1 NodeHostName=ltlsbubble1 Version=24.11.4* in normal mode NodeAddr is the same than NodeName , so it use DNS resolution for communication. to verify my hypothesis, i go to the c code of slurm, identify the register function and replace it with the same mechanism than normal node in src/slurmctld/node_mgr.c i replace : set_node_comm_name(node_ptr, *comm_name*, reg_msg->hostname); by set_node_comm_name(node_ptr, NULL, reg_msg->hostname); i rebuild slutmctld with this patch and try it with dynamic mode , it works like expected *scontrol show nodeNodeName=ltlsbubble1 Arch=x86_64 CoresPerSocket=4..NodeAddr=ltlsbubble1 NodeHostName=ltlsbubble1 Version=24.1* no ip in nodeAddr , but only the nodename, so it use DNS resolution . the node works fine and no goes down for timeout ping so my question : can we have an option to force DNS resolution instead ip discover in Dynamic mode ? ( i try the option cloud_dns, but it not seems the purpose of this option) best regard, Stephane

1 0

pam_slurm_adopt ambiguity in instructions and with ssd
by Robert Kudyba 21 Apr '25

21 Apr '25

In the instructions for pam_slurm_adopt <https://slurm.schedmd.com/pam_slurm_adopt.html#ssh_config>, there are instructions such as: > > Add the following line to the appropriate file in /etc/pam.d, such as > system-auth or sshd (you may use either the "required" or "sufficient" > PAM control flag): This module is configurable. Add these options to the end of the > pam_slurm_adopt line in the appropriate file in /etc/pam.d/ (e.g., sshd > or system-auth): Assuming an OS like CentOS does this mean it should be put in both? slurm.conf on the node has: UsePAM yes slurm.conf has PrologFlags=contain and ProctrackType=proctrack/cgroup I placed the call here only in /etc/pam.d/sshd making sure it is the last line in the account stack. #%PAM-1.0 auth required pam_sepermit.so auth substack system-auth auth include postlogin # Used with polkit to reauthorize users in remote sessions -auth optional pam_reauthorize.so prepare account required pam_nologin.so account include system-auth -account required pam_slurm_adopt.so so pam_sss.so is at the bottom of /etc/pam.d/sshd session optional pam_keyinit.so revoke session required pam_limits.so #-session optional pam_systemd.so session optional pam_oddjob_mkhomedir.so umask=0022 skel=/etc/skel session [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid session required pam_unix.so session optional pam_sss.so We're testing this on an idle node. I start an interactive srun. However trying to ssh to the node gets: Apr 18 11:13:41 node11 sshd[33355]: Authorized to dk2643, krb5 principal user(a)ouruni.EDU (ssh_gssapi_krb5_cmdok) Apr 18 11:13:41 node11 sshd[33355]: pam_sss(sshd:account): Access denied for user user: 6 (Permission denied) Apr 18 11:13:41 node11 sshd[33355]: fatal: Access denied for user user by PAM account configuration [preauth] Am I missing something?

3 5

knl_generic.conf seems to be ignored and Slurm adopts default settings which specify Intel motherboard and syscfg - need help to figure out why Slurm is not reading my Dell knl_generic.conf parameters
by Bryan Johnston 19 Apr '25

19 Apr '25

Hi folks I'm in the process of standing up some Stampede2 Dell C3620p KNL nodes and I seem to be hitting a blind spot. I previously "successfully" configured KNL's on an Intel board (S7200AP), with OpenHPC and Rocky8. I say "successfully" because it works but evidently my latest troubleshooting has revealed that I may have been lucky rather than an expert KNL integrator :-) I thought I knew what I was doing, but after repeating my Intel KNL recipe with the Dell system, I have unearthed my ignorance with this wonderful (but deprecated) technology (anecdotally, the KNLs offer excellent performance and power efficiency for our workloads, particularly when contrasted with our alternative available hardware). The first discovery was the "syscfg" for Intel boards is not the same as the "syscfg" for Dell boards. I've since sorted this out. The second discovery was made while troubleshooting an issue that I'm hitting. After realising that the slurmd client nodes don't seem to be reading the "knl_generic.conf" parameters that are specified in /etc/slurm on the smshost (OpenHPC parlance for head node ... And it's a Slurm config less set up), I think my original Intel solution was working out of luck more than ingenuity. For reference , the Slurm configuration for KNL now includes: ``` NodeFeaturesPlugins=knl_generic DebugFlags=NodeFeatures GresTypes=hbm ``` And I've created a separate "knl_generic.conf" that points to the Dell specific tools and features. For the Dell system, slurmd seems to ignore my knl_generic.conf file and is drawing defaults from somewhere else. Slurm still considers SystemType to be Intel, SyscfgPath to be the default location, and SyscfgTimeout to be 1000. For Dell systems, Slurm needs to have SystemType=Dell and Timeout to be 1000. I don't understand why the nodes are not reading the knl_generic file - any help or clues would be appreciated. Here's my theory on what is happening: The Intel KNL system was successful by luck ... It probably exhibited the same ignore-the-config-file but ran default NodeFeatures for some generic knl_generic settings which are stored somewhere as default parameters. I must have just lucked out when I was using my Intel KNL system because it was using the defaults (that are compatible with Intel). If this assumption is correct, the Dell system is not working because it isn't compatible with the Intel defaults. Any clues on how to successfully invoke the config file (or better debuggingtechniwues to figure out why it isn't) would be appreciated. I can share journalctl feedback if necessary. For now, I've tried changing ownership of the config files to root:slurm, copied knl_generic.conf to the compute nodes' /etc/slurm/ and also tried to specify the config file by running (on the compute nodes) "slurmd" with "-f" ... No joy; if slurmd runs successfully (when I don't screw up some random experimental settings) then it always seems to ignore knl_generic.conf and loads some default settings from somewhere. A few questions: 1. Are there default settings stored somewhere? I might be barking up the wrong tree, although I've looked for files that may clash with the config file I've created but can't find any. 2. Is there a better way to force the knl_generic file to be loaded? 3. Is the configless Slurm somehow not reading the knl_generic file to the clients? I understand that all configuration files are read from the host server. Many thanks for any help! Regards / Groete / Sala(ni) Kahle - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Bryan Johnston Senior HPC Technologist II Lead: HPC Ecosystems Project HPCwire 2024's Outstanding Leader in HPC CHPC | www.chpc.ac.za | NICIS | nicis.ac.za Centre for High Performance Computing If you receive an email from me out of office hours for you, please do not feel obliged to respond during off-hours! Book time to meet with me<https://outlook.office.com/bookwithme/user/87af4906a703488386578f34e4473c74…>

1 0

Issue with Enforcing GPU Usage Limits in Slurm
by lyz＠simplehpc.com 16 Apr '25

16 Apr '25

Hi, I am currently encountering an issue with Slurm's GPU resource limitation. I have attempted to restrict the number of GPUs a user can utilize by executing the following command: sacctmgr modify user lyz set MaxTRES=gres/gpu=2 This command is intended to limit user 'lyz' to using a maximum of 2 GPUs. However, when the user submits a job using srun, specifying CUDA 0, 1, 2, and 3 in the job script, or os.environ["CUDA_VISIBLE_DEVICES"] = "0,1,2,3", the job still utilizes all 4 GPUs during execution. This indicates that the GPU usage limit is not being enforced as expected. How can I resolve this situation.

4 14

pam_slurm_adopt and multiple jobs on the same worker node
by Massimo Sgaravatto 14 Apr '25

14 Apr '25

Dear all With the pam_slurm_adopt module as far as I understand you can ssh to a worker node if there is at least a job running on the node by that user. If there are multiple jobs, if I am not wrong you will be "mapped" to the last job started on the node. And, if you are using cgroups, you will be "confined" to the resources assigned to this "last" job. Is it possible in some way to specify the job to be mapped, in case there are multiple jobs for that user on the same node ? Thanks, Massimo

2 2

sllurmrestd via unix socket
by Brian Andrus 10 Apr '25

10 Apr '25

All, Maybe someone has seen this. I have slurmrestd running listening on port 8081 as well as a unix socket at /run/slurmrestd/slurmrestd.sock I am able to query the port with curl and do a ping. Everything seems fine. Other commands work as well. "pings": [ { "hostname": "head01", "pinged": "UP", "responding": true, "latency": 1605, "mode": "primary", "primary": true }, { "hostname": "head02", "pinged": "UP", "responding": true, "latency": 2353, "mode": "backup", "primary": false } When I try doing so via socket, however, my two head nodes show 'DOWN' : "pings": [ { "hostname": "head01", "pinged": "DOWN", "latency": 11784, "mode": "primary" }, { "hostname": "head02", "pinged": "DOWN", "latency": 12668, "mode": "backup" } Other commands fail with: "error_number": 1007, "error": "Protocol authentication error", I'll admit, I don't usually use sockets, so I could easily be overlooking something there. Permissions on the socket look right. I am getting json back, so it is connecting. Note: slurmrestd is running under it's own user (not root and not slurmuser). Any ideas? Thanks in advance, Brian Andrus

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