Please do not run your production jobs on the login nodes. The login nodes are limited in number and shared among all of the users. The compute nodes on the other hand are dedicated to running a specific number of job processes at any given time. They are what your jobs should run on. Any long running jobs found running on a login node will be terminated, with the exception of localized job control scripts that are sometimes needed.
HPC login nodes serve as an access point for users wishing to run jobs on the ITS-RS HPC system. When you log in you will be placed in a round-robin fashion on one of the available login nodes for the cluster.
Login nodes are intended for basic tasks such as uploading data, managing files, compiling software, editing scripts, and checking on or managing your jobs. Small-scale interactive work may also be acceptable if your resource requirements are minimal. Remember that when you are using a login node, there are generally many other people also using the same login node. Using too many resources on a login node may negatively affect the ability of other people to complete their work. In order to help with this, there is a per user CPU quota active on the login nodes that will help prevent over consumption of resources.
Login nodes on the clusters have memory limits, so please be aware that if you run a process on the login node that goes beyond a certain amount, it may be killed.
On Argon, there is a 16G memory limit per user, for all processes owned by the user. Finally, we reserve the right to terminate any process that we feel is interfering with the ability of others to complete work, irrespective of its resource usage.
java -Xmx1g ...
DUO
Duo two-facter Authentication is in place on all HPC clusters. In order to properly use the login nodes, ensure that you have duo configured. More info here: Two-factor authentication
cron jobs
You may want to use cron jobs to automate reoccurring aspects of a workflow, such as checking for new data or submitting cluster jobs to process it. Argon's login nodes share a cron directory so you can manage all your cron jobs in one location, and a single login node will run them. You can use cron syntax and features supported by the "cronie" implementation of cron present in CentOS 7.
SGE in cron
Note that cron's default environment is unlike normal shell sessions and lacks some typical features and configuration. In particular, if you use any SGE commands in your cron jobs or in scripts you call, you first need to configure SGE's environment variables by sourcing whichever sge.* script in /etc/profile.d is appropriate for your shell interpreter. Versions are available for Bourne and C family shells:
/etc/profile.d/sge.sh/etc/profile.d/sge.csh