Introduction and Getting Access (1)

By Hongyu Xiao

Introduction

This guide will walk you through the process of setting up and managing your workflow on a computing cluster. While it focuses on the University of Oklahoma Cluster, the general principles apply to other clusters as well. I'll cover the essential steps from initial access to job submission and monitoring.

1. Getting Access

Request cluster access: Contact your system administrator or IT department for credentials
1. Get your OU account, which will be your primary login credentials for accessing the cluster. Make sure to set a strong password and keep it secure.
1. Get an account on OSCER computers: Fill out the New Account Request Form.
  
  Once you have your OSCER account, you can log in using SSH. Here's how:
```
# Basic SSH login
ssh username@schooner.oscer.ou.edu

# If you need X11 forwarding for graphical applications
ssh -X username@schooner.oscer.ou.edu
```
  Replace 'username' with your actual OSCER username. You will be prompted for your password unless you've set up SSH keys.
  If you're using Windows, you can use Windows Subsystem for Linux (WSL) to establish SSH connections.
1. For OGS work, you can apply for membership with the Data Institute for Societal Challenges to get GPU resources. The application form is available here. If the link expires, please check the DISC Resource page.
1. Once access is granted, you'll receive an email. Make sure to change your password upon first login using the passwd command.
  
  Example of changing password:
```
[username@schooner ~]$ passwd
Changing password for user username.
Current password: [Enter your current password]
New password: [Enter your new password]
Retype new password: [Enter your new password again]
passwd: all authentication tokens updated successfully.
```
  Note: When typing passwords, no characters will appear on the screen for security reasons. I recommend using a strong password that includes a mix of uppercase and lowercase letters, numbers, and special characters.

Set up SSH keys: Generate and configure SSH keys for secure authentication

Example of generating and setting up SSH keys:

# Generate SSH key pair on your local machine
ssh-keygen -t rsa -b 4096

# You will see prompts like this:
# Enter file in which to save the key (/home/username/.ssh/id_rsa):
# Enter passphrase (empty for no passphrase):
# Enter same passphrase again:

# Copy your public key to the cluster
ssh-copy-id username@schooner.oscer.ou.edu

# Alternative manual method if ssh-copy-id is not available
cat ~/.ssh/id_rsa.pub | ssh username@schooner.oscer.ou.edu "mkdir -p ~/.ssh && chmod 700 ~/.ssh && cat >> ~/.ssh/authorized_keys && chmod 600 ~/.ssh/authorized_keys"

After setting up SSH keys, you can log in without entering your password each time. Keep your private key (id_rsa) secure and never share it.

Test connection: Verify access using SSH command:

ssh username@schooner.oscer.ou.edu

Here's an example of testing your SSH connection and X11 forwarding:

# First, try a basic SSH login
ssh username@schooner.oscer.ou.edu

# After successful login, you should see something like:
[username@schooner ~]$

# To test X11 forwarding, first logout and reconnect with -X flag
exit
ssh -X username@schooner.oscer.ou.edu

# Test X11 forwarding by running xclock
xclock

# If a clock window appears on your screen, X11 forwarding is working correctly
# Press Ctrl+C in the terminal to close xclock

On my screen it looks like this;

If xclock doesn't work, verify that you have X11 server installed on your local machine. For Windows users, you'll need an X server like Xming or VcXsrv.

Technical Support:For technical assistance, OU OSCER maintains a dedicated help desk. You can contact them atsupport@oscer.ou.edu. They also offer comprehensive online documentation athttps://www.ou.edu/oscer/support.