[slurm-users] Submit job using srun fails but sbatch works

Ole Holm Nielsen Ole.H.Nielsen at fysik.dtu.dk
Wed May 29 13:12:50 UTC 2019


Hi Alexander,

The error "can't find address for host cn7" would indicate a DNS 
problem.  What is the output of "host cn7" from the srun host li1?

How many network devices are in your subnet?  It may be that the Linux 
kernel is doing "ARP cache trashing" if the number of devices approaches 
512.  What is the result of "arp cn7"?

To fix ARP cache trashing look in my Slurm Wiki page
https://wiki.fysik.dtu.dk/niflheim/Slurm_configuration#configure-arp-cache-for-large-networks

Best regards,
Ole

On 5/29/19 3:00 PM, Alexander Åhman wrote:
> Hi,
> Have a very strange problem. The cluster has been working just fine 
> until one node died and now I can't submit jobs to 2 of the nodes using 
> srun from the login machine. Using sbatch works just fine and also if I 
> use srun from the same host as slurmctld.
> All the other nodes works just fine as they always has, only 2 nodes are 
> experiencing this problem. Very strange...
> 
> Have checked network connectivity and DNS and that is OK. I can ping, 
> ssh to all nodes just fine. All nodes are identical and using Slurm 18.08.
> Also tested to reboot the 2 nodes and slurmctld but still same problem.
> 
> [alex at li1 ~]$ srun -w cn7 hostname
> srun: error: fwd_tree_thread: can't find address for host cn7, check 
> slurm.conf
> srun: error: Task launch for 1088816.0 failed on node cn7: Can't find an 
> address, check slurm.conf
> srun: error: Application launch failed: Can't find an address, check 
> slurm.conf
> srun: Job step aborted: Waiting up to 32 seconds for job step to finish.
> srun: error: Timed out waiting for job step to complete
> 
> [alex at li1 ~]$ srun -w cn6 hostname
> cn6.ydesign.se
> 
> What is this error "can't find address for host" about? Have searched 
> the web but can't find any good information about what the problem is or 
> what to do to resolve it.
> 
> Any kind soul out there who knows what to do next?



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