job state=failed reason=nonzero exit code, SLURM

Question

I'm new to Slurm, I have been trying to run a simple job. I'm running Slurm on top of a VM. Here's my slurm.conf:

SlurmctldHost=master
#SlurmctldHost=
#
#DisableRootJobs=NO
#EnforcePartLimits=NO
#Epilog=
#EpilogSlurmctld=
#FirstJobId=1
#MaxJobId=999999
#GresTypes=
#GroupUpdateForce=0
#GroupUpdateTime=600
#JobFileAppend=0
#JobRequeue=1
#JobSubmitPlugins=1
#KillOnBadExit=0
#LaunchType=launch/slurm
#Licenses=foo*4,bar
#MailProg=/bin/mail
#MaxJobCount=5000
#MaxStepCount=40000
#MaxTasksPerNode=128
MpiDefault=none
#MpiParams=ports=#-#
#PluginDir=
#PlugStackConfig=
#PrivateData=jobs
ProctrackType=proctrack/cgroup
#Prolog=
#PrologFlags=
#PrologSlurmctld=
#PropagatePrioProcess=0
#PropagateResourceLimits=
#PropagateResourceLimitsExcept=
#RebootProgram=
ReturnToService=1
#SallocDefaultCommand=
SlurmctldPidFile=/var/run/slurmctld.pid
SlurmctldPort=6817
SlurmdPidFile=/var/run/slurmd.pid
SlurmdPort=6818
SlurmdSpoolDir=/var/spool/slurmd
SlurmUser=slurm
#SlurmdUser=root
#SrunEpilog=
#SrunProlog=
StateSaveLocation=/var/spool
SwitchType=switch/none
#TaskEpilog=
TaskPlugin=task/affinity
TaskPluginParam=Sched
#TaskProlog=
#TopologyPlugin=topology/tree
#TmpFS=/tmp
#TrackWCKey=no
#TreeWidth=
#UnkillableStepProgram=
#UsePAM=0
#
#
# TIMERS
#BatchStartTimeout=10
#CompleteWait=0
#EpilogMsgTime=2000
#GetEnvTimeout=2
#HealthCheckInterval=0
#HealthCheckProgram=
InactiveLimit=0
KillWait=30
#MessageTimeout=10
#ResvOverRun=0
MinJobAge=300
#OverTimeLimit=0 
SlurmctldTimeout=120
SlurmdTimeout=300
#UnkillableStepTimeout=60
#VSizeFactor=0
Waittime=0
#
#
# SCHEDULING
#DefMemPerCPU=0
FastSchedule=1
#MaxMemPerCPU=0
#SchedulerTimeSlice=30
SchedulerType=sched/backfill
SelectType=select/cons_res
SelectTypeParameters=CR_Core
#
#
# JOB PRIORITY
#PriorityFlags=
#PriorityType=priority/basic
#PriorityDecayHalfLife=
#PriorityCalcPeriod=
#PriorityFavorSmall=
#PriorityMaxAge=
#PriorityUsageResetPeriod=
#PriorityWeightAge=
#PriorityWeightFairshare=
#PriorityWeightJobSize=
#PriorityWeightPartition=
#PriorityWeightQOS=
#
#
# LOGGING AND ACCOUNTING
#AccountingStorageEnforce=0
#AccountingStorageHost=
#AccountingStorageLoc=
#AccountingStoragePass=
#AccountingStoragePort=
AccountingStorageType=accounting_storage/none
#AccountingStorageUser=
AccountingStoreJobComment=YES
ClusterName=cluster
#DebugFlags=
#JobCompHost=
#JobCompLoc=
#JobCompPass=
#JobCompPort=
JobCompType=jobcomp/none
#JobCompUser=
#JobContainerType=job_container/none
JobAcctGatherFrequency=30
JobAcctGatherType=jobacct_gather/none
SlurmctldDebug=info
SlurmctldLogFile=/var/log/slurmctld.log
SlurmdDebug=info
SlurmdLogFile=/var/log/slurmd.log
#SlurmSchedLogFile=
#SlurmSchedLogLevel= 
#
#
# POWER SAVE SUPPORT FOR IDLE NODES (optional)
#SuspendProgram=
#ResumeProgram=
#SuspendTimeout=
#ResumeTimeout=
#ResumeRate=
#SuspendExcNodes=
#SuspendExcParts=
#SuspendRate=
#SuspendTime=
#
#

# COMPUTE NODES
NodeName=slave[1-2] CPUs=3 RealMemory=4184 Sockets=3 CoresPerSocket=1 
ThreadsPerCore=1 State=UNKNOWN
PartitionName=debug Nodes=slave[1-2] Default=YES MaxTime=INFINITE State=UP

Here's my cgroup.conf:

AllowedDevicesFile="/etc/slurm/cgroup_allowed_devices_file.conf"
ConstrainCores=no
TaskAffinity=no
ConstrainRAMSpace=yes
ConstrainSwapSpace=no
ConstrainDevices=no
AllowedRamSpace=100
AllowedSwapSpace=0
MaxRAMPercent=100
MaxSwapPercent=100
MinRAMSpace=30

This is the code I'm trying to run:

#include <stdio.h>
#include <math.h>

double func(double);

double func(double a)
{
    return (4.0 / (1.0 + a*a));
}

int main(int args, char * argv[])
{
    int n = 10000;  // number of rectangles
    double base = 1.0/n;
    int i;
    double sum_area = 0.0;
    double x,h;
//printf("base = %f\n", base);

for (i=0; i<n; i++)
{
    x = base*(i+0.5);
    h = func(x);
    sum_area += base*h;
    printf("i = %d\n", i);
    printf("x = %f\n", x);
    printf("h = %f\n", h);
    printf("sum_area = %f\n", sum_area);

}

printf("pi = %.16f\n", sum_area) ;
}

I have tested it and all working properly but when I sbatch'it:

#!/bin/bash
#SBATCH --job-name=pi_serial
#SBATCH --output=slurm.out
#SBATCH --error=slurm.err
#SBATCH --ntasks=1

./pi_serial

sLURM gives it a job ID, but in the squeue, I find nothing. I have executed the job by running sbatch -vvv test_slurm.sh and here's a problem that I can spot jobstate=failed reason=nonzero exit code=1:0

Any thoughts on how to get this working?