Refer to Key Components for HPC Cluster Setup; for which pieces you need to setup.

This guide provides step-by-step instructions for setting up the Slurm controller daemon (`slurmctld`) on Ubuntu 22.04. It also includes common errors encountered during the setup process and how to resolve them.

Step 1: Install Prerequisites

To begin, install the required dependencies for Slurm and its components:

sudo apt update && sudo apt upgrade -y
sudo apt install -y munge libmunge-dev libmunge2 build-essential man-db mariadb-server mariadb-client libmariadb-dev python3 python3-pip chrony

Step 2: Configure Munge (Authentication for slurm)

Munge is required for authentication within the Slurm cluster.

1. Generate a Munge key on the controller node:
sudo create-munge-key

2. Copy the key to all compute nodes:
scp /etc/munge/munge.key user@node:/etc/munge/

3. Start the Munge service:
sudo systemctl enable –now munge

Step 3: Install Slurm

1. Download and compile Slurm:
wget https://download.schedmd.com/slurm/slurm-23.02.4.tar.bz2
tar -xvjf slurm-23.02.4.tar.bz2
cd slurm-23.02.4
./configure –prefix=/usr/local/slurm –sysconfdir=/etc/slurm
make -j$(nproc)
sudo make install

2. Create necessary directories and set permissions:
sudo mkdir -p /etc/slurm /var/spool/slurm /var/log/slurm
sudo chown slurm: /var/spool/slurm /var/log/slurm

3. Add the Slurm user:
sudo useradd -m slurm

Step 4: Configure Slurm; more complex configs contact Nick Tailor

1. Generate a basic `slurm.conf` using the configurator tool at
https://slurm.schedmd.com/configurator.html. Save the configuration to `/etc/slurm/slurm.conf`.

# Basic Slurm Configuration

ClusterName=my_cluster

ControlMachine=slurmctld # Replace with your control node’s hostname

# BackupController=backup-slurmctld # Uncomment and replace if you have a backup controller

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# Authentication

AuthType=auth/munge

CryptoType=crypto/munge

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# Logging

SlurmdLogFile=/var/log/slurm/slurmd.log

SlurmctldLogFile=/var/log/slurm/slurmctld.log

SlurmctldDebug=info

SlurmdDebug=info

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# Slurm User

SlurmUser=slurm

StateSaveLocation=/var/spool/slurm

SlurmdSpoolDir=/var/spool/slurmd

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# Scheduler

SchedulerType=sched/backfill

SchedulerParameters=bf_continue

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# Accounting

AccountingStorageType=accounting_storage/none

JobAcctGatherType=jobacct_gather/linux

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# Compute Nodes

NodeName=node[1-2] CPUs=4 RealMemory=8192 State=UNKNOWN

PartitionName=debug Nodes=node[1-2] Default=YES MaxTime=INFINITE State=UP

2. Distribute `slurm.conf` to all compute nodes:
scp /etc/slurm/slurm.conf user@node:/etc/slurm/

3. Restart Slurm services:
sudo systemctl restart slurmctld
sudo systemctl restart slurmd

Troubleshooting Common Errors

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root@slrmcltd:~# tail /var/log/slurm/slurmctld.log

[2024-12-06T11:57:25.428] error: High latency for 1000 calls to gettimeofday(): 20012 microseconds

[2024-12-06T11:57:25.431] fatal: mkdir(/var/spool/slurm): Permission denied

[2024-12-06T11:58:34.862] error: High latency for 1000 calls to gettimeofday(): 20029 microseconds

[2024-12-06T11:58:34.864] fatal: mkdir(/var/spool/slurm): Permission denied

[2024-12-06T11:59:38.843] error: High latency for 1000 calls to gettimeofday(): 18842 microseconds

[2024-12-06T11:59:38.847] fatal: mkdir(/var/spool/slurm): Permission denied

Error: Permission Denied for /var/spool/slurm

This error occurs when the `slurm` user does not have the correct permissions to access the directory.

Fix:
sudo mkdir -p /var/spool/slurm
sudo chown -R slurm: /var/spool/slurm
sudo chmod -R 755 /var/spool/slurm

Error: Temporary Failure in Name Resolution

Slurm could not resolve the hostname `slurmctld`. This can be fixed by updating `/etc/hosts`:

1. Edit `/etc/hosts` and add the following:
127.0.0.1 slurmctld
192.168.20.8 slurmctld

2. Verify the hostname matches `ControlMachine` in `/etc/slurm/slurm.conf`.

3. Restart networking and test hostname resolution:
sudo systemctl restart systemd-networkd
ping slurmctld

Error: High Latency for gettimeofday()

Dec 06 11:57:25 slrmcltd.home systemd[1]: Started Slurm controller daemon.

Dec 06 11:57:25 slrmcltd.home slurmctld[2619]: slurmctld: error: High latency for 1000 calls to gettimeofday(): 20012 microseconds

Dec 06 11:57:25 slrmcltd.home systemd[1]: slurmctld.service: Main process exited, code=exited, status=1/FAILURE

Dec 06 11:57:25 slrmcltd.home systemd[1]: slurmctld.service: Failed with result ‘exit-code’.

This warning typically indicates timing issues in the system.

Fixes:
1. Install and configure `chrony` for time synchronization:
sudo apt install chrony
sudo systemctl enable –now chrony
   chronyc tracking
timedatectl
2. For virtualized environments, optimize the clocksource:
sudo echo tsc > /sys/devices/system/clocksource/clocksource0/current_clocksource

3. Disable high-precision timing in `slurm.conf` (optional):
HighPrecisionTimer=NO
sudo systemctl restart slurmctld

Step 5: Verify and Test the Setup

1. Validate the configuration:
scontrol reconfigure
– no errors mean its working. If this doesn’t work check the connection between nodes
update your /etc/hosts to have the hosts all listed across the all machines and nodes.

2. Check node and partition status:
sinfo

root@slrmcltd:/etc/slurm# sinfo

PARTITION AVAIL TIMELIMIT NODES STATE NODELIST

debug* up infinite 1 idle* node1

3. Monitor logs for errors:
sudo tail -f /var/log/slurm/slurmctld.log

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Written By: Nick Tailor