Getting an account

First, you need to get an account from NOTUR, the webpage for you request is : ​https://www.metacenter.no/user/application/form/notur/.

ssh configuration

You can add the following lines to ~/.ssh/config on your local machine:

Host hexagon hexagon.hpc.uib.no
    HostName hexagon.hpc.uib.no
    User YOURHEXAGONUSERNAME

and replace YOURHEXAGONUSERNAME by your hexagon username.

Once this is done, you can ssh hexagon by simply doing:

ssh hexagon

Password-less ssh

Once you have the account, you can setup a public key authentification in order to avoid having to input your password for each run. You need to have a SSH public/private key pair. If you do not, you can create a SSH public/private key pair by typing the following command and following the prompts (no passphrase necessary):

$your_localhost% ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/Users/username/.ssh/id_rsa):RETURN
Enter passphrase (empty for no passphrase):RETURN
Enter same passphrase again:RETURN
Your identification has been saved in /Users/username/.ssh/id_rsa.
Your public key has been saved in /Users/username/.ssh/id_rsa.pub.

Two files were created: your private key /Users/username/.ssh/id_rsa, and the public key /Users/username/.ssh/id_rsa.pub. The private key is read-only and only for you, it is used to decrypt all correspondence encrypted with the public key. The contents of the public key need to be copied to ~/.ssh/authorized_keys on your hexagon account:

$your_localhost%scp ~/.ssh/id_rsa.pub username@your_remosthost:~

Now on Hexagon, copy the content of id_rsa.pub:

$your_remosthost%cat ~/id_rsa.pub >> ~/.ssh/authorized_keys
$your_remosthost%rm ~/id_rsa.pub

Environment

On Hexagon, add the following lines to ~/.bashrc:

export ISSM_DIR=PATHTOTRUNK
export CRAYPE_LINK_TYPE=dynamic
#
module unload xtpe-interlagos
module unload notur
#
module load craype-barcelona
module load automake
module load cray-petsc
module load cray-tpsl
module load cray-mpich
module load gsl

Log out and log back in to apply this change.

Installing ISSM on Hexagon

You can check out ISSM and install m1qn3. This is the only package we will install, the module loaded from your bashrc are taking care of the rest.

Copy the Hexagon configuration script from the configs directory and rename it:

cp configs/config-linux64-hexagon.sh configure.sh

When running autotools you may run into the following error message :

src/c/Makefile.am:9: Libtool library used but `LIBTOOL' is undefined
src/c/Makefile.am:9:   The usual way to define `LIBTOOL' is to add `LT_INIT'
src/c/Makefile.am:9:   to `configure.ac' and run `aclocal' and `autoconf' again.
src/c/Makefile.am:9:   If `LT_INIT' is in `configure.ac', make sure
src/c/Makefile.am:9:   its definition is in aclocal's search path.

running libtoolize should solve this issue.

Due to the fact that the autotool on this machine is getting old you should comment the following line in src/c/main/EnvironmentInit.cpp :

if(!my_rank) printf("(website: %s contact: %s)\n",PACKAGE_URL,PACKAGE_BUGREPORT);

hexagon_settings.m

TO BE DONE function of hexagon.py

Running jobs on Hexagon

TO BE UPDATED

On Hexagon, you can use up to 30 cores per node. The more nodes and the longer the requested time, the more you will have to wait in the queue. So choose your settings wisely:

md.cluster=hexagon('numnodes',1,'cpuspernode',8);
md.cluster.time=10;

to have a maximum job time of 10 minutes and 8 cores on one node. If the run lasts longer than 10 minutes, it will be killed and you will not be able to retrieve your results.

Now if you want to check the status of your job and the queue you are using, type in the bash with the Greeplanet session:

squeue -u username

You can delete your job manually by typing:

scancel JOBID

where JOBID is the ID of your job (indicated in the Matlab session). Matlab indicates too the directory of your job where you can find the files JOBNAME.outlog and JOBNAME.errlog. The outlog file contains the informations that would appear if you were running your job on your local machine and the errlog file contains the error information in case the job encounters an error.

If you want to load results from the cluster manually (for example if you have an error due to an internet interruption), you find in the informations Matlab gave you /home/srebuffi/trunk-jpl/execution//SOMETHING/JOBNAME.lock , you copy the SOMETHING and you type in Matlab:

md=loadresultsfromcluster(md,'SOMETHING');

A comparision of PBS to slurm commands can be found here: ​http://slurm.schedmd.com/rosetta.pdf