HP XC System 2.x Software - Manual (Page 75)

If you specify a script at the end of the srun command line (not as an argument to -A ), the
spawned shell executes that script using the allocated resources (interactively, without a queue).
See the
-b option for script requirements.
If you specify no script, you can then execute other instances of srun interactively, within the
spawned subshell, to run multiple parallel jobs on the resources that you allocated to the subshell.
Resources (such as nodes) will only be freed for other jobs when you terminate the subshell.
-a=jobid ( --attach=jobid )
The -a=jobid option attaches (or reattaches) your current srun session to the already
running job whose SLURM ID is jobid . The job to which you attach must have its resources
managed by SLURM, but it can be either interactive ("allocated," started with -A ) or batch
(started with - -b ). This option allows you to monitor or intervene in previously started srun
jobs. You cannot use -a with -b or -A . Because the running job to which you attach already
has its resources specified, you cannot use -a with -n , -N , or -c . You can only attach to
jobs for which you are the authorized owner.
By default, -a attaches to the designated job read-only. stdout and stderr are copied to
the attaching srun , just as if the current srun session had started the job. However, signals
are not forwarded to the remote processes (and a single Ctrl/C will detach the read-only srun
from the job).
If you use -j ( -join ) or -s ( -steal) along with -a , your srun session joins the running
job and can also forward signals to it as well as receive stdout and stderr from it. If you
join a SLURM batch ( -b ) job, you can send signals to its batch script. Join ( -j ) does not
forward stdin , but steal ( -s , which closes other open sessions with the job) does forward
stdin as well as signals.
-j ( --join )
The -j option joins a running SLURM job (always used only with -a option to specify the
jobid). This not only duplicates stdout and stderr to the attaching srun session, but it
also forwards signals to the job’s script or processes as well.
-s ( --steal )
The -s option steals all connections to a running SLURM job (always used only with -a
option to specify the jobid). -steal closes any open sessions with the specified job, then
copies stdout and stderr to the attaching srun session, and it also forwards both signals
and stdin to the job’s script or processes.
6.4.4 srun Resource-Allocation Options
The srun options assign compute resources to your parallel SLURM-managed job. These
options can be used alone or in combination. Also, refer to the other srun options that can
affect node management for your job, especially the control options and constraint options.
-n procs ( --nprocs=procs )
The -n procs option requests that srun execute procs processes. To control how these
processes are distributed among nodes and CPUs, combine -n with -c or -N as explained
below (default is one process per node).
-N n ( --nodes=n )
The -N n option allocates at least n nodes to this job, where n may be one of the following:
• a specific node count (such as -N 16)
• a node count range (such as -N 14-18)
Using SLURM 6-5