Login NodesA login node serves as a staging area where you can perform housekeeping work, edit scripts, and submit job requests for execution on one/some of the cluster’s compute nodes. It is important to know that the login nodes are not the location where scripts are run. Heavy computation on the login nodes slows the system down for all users and will not give you the resources or performance you need. It should also be stressed that software is not available on the login nodes. General practices: - Know when you are on a login node. You can use your Linux prompt or the "hostname" command. It is where you land when you choose
shell from the bastion node. To differentiate, the bastion host (gatekeeper, or keymaster) is a secure portal from the outside and serves no compute function. - Appropriate activities: edit and manage files, request interactive sessions, submit jobs, and track jobs.
- Avoid computationally intensive activity.
a. Don't run research applications. Use an interactive session if running a job is not appropriate. b. Don't launch too many simultaneous processes. c. That script you run to monitor job status several times a second should probably run every few minutes. d. I/O activity can slow the login node for everyone, like multiple copies or "ls -l" on directories with 000's of files.
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