Getting Started with the Cluster

The cluster has recently been refreshed to Rocky Linux 9 (Enterprise Linux 9) and you can now fully access the nodes from your web browser. To do so:

Connect to the university VPN.

Once connected, go to one of the following addresses in your browser:

You will be greeted with a login screen. Please use your UMD username and password (the same you would use with CAS) to log in to the server.

If successful, you will now be at the cluster node's dashboard.

The dashboard is a web-based interface that will allow you to do most anything you'll need to do with the node.

You'll typically start at the overview module, which will give you the following:

1: The navigation pane. This will allow you to move between different modules of the dashboard. You'll primarily use Overview, Navigator, and Terminal. The pane you select will be shown on the right side of the screen. This bar will persist between modules.

2: The server's message of the day (MOTD). This will be updated with any relevant notices or alerts.

3: The server's current utilization. You can see here if the server is being heavily utilized, so you can move to another, less-active node if needed.

4: The server's current hardware status. This shows the make and model of the current server, and how long it has been active without a restart.

This module will allow you to securely upload and download files from the cluster. If you are unsure of what the buttons do, you can hover over them to gain a description of their function.

1: Favorites button (has home by default, but can add other folders once you navigate to them)

2: Edit path (manually enter folder location)

3: Current directory path. Can click on previous folders to go “up” a directory.

4: Upload File

5: Folder window. Shows contents of current folder. You can use right click to perform file functions such as downloading and editing

6: Properties of currently selected item

This module provides an SSH connection to the current cluster.

1: The current user, node, and working directory.

2: The main terminal window, where you issue commands and read standard output.

3: Context (Right-click) menu in the terminal window. Allows for copy/paste and shows keyboard command equivalents (NOTE: The browser may need to ask if it can access clipboard content. Allow for this function to work.)

4: Terminal options (Font size / Background Color)

From the Linux prompt you can move your files around, check on your jobs, manage your disk space, and run programs. Below are some brief introductions to basic commands. For more info, this is a reasonably good tutorial. Note that most of the the Linux shell functionality is the same as a UNIX shell (the shell that you get when you open a Mac terminal). There are many resources online to help you learn how to use the Unix shell.

The ls command lists the files in a particular directory. To use it, type ls at the prompt and press enter:

[username@econ1 ~ ]$ ls

You can use wildcards with ls to list only files matching a particular expression. That is, the command

[username@econ1 ~ ]$ ls *.do

will list only your .do files in the current directory.

The mv command allows you to move files or directories from one directory to another

mv [file] [directory]

The mkdir command creates a new directory. It's usage is

mkdir [new directory name]

The rm command deletes the files specified after the command. The following code would delete all .do files in your current directory.

rm *.do

You can delete an entire non-empty directory with:

rm -r [directory]

The command rmdir deletes an empty directory:

rmdir [directory to delete]

To get help about a command, you can view it's “man page,” which describes how the command works. It describes the syntax and usage for the command. To view a man page, type:

man [command]

You can move up and down the man page with the arrows. Typing q quits.

Sometimes you use a certain command so many times that you just can't type it anymore. That's where the aliases come helpful. Just as the name suggests, you can tell the cluster to use some new (shorter) command in place of the one you use often. As an example, every time I log in to the cluster, I go to cd ~/files/pics/cute_pics/cats and I want to change it to just cats.

First, I start editing my bash profile with any text editor. For example

nano ~/.bash_profile

Then I go to the space below # User specific environment and startup programs and type

alias cats="cd ~/files/pics/cute_pics/cats"

I save the file and refresh the changes by typing

source ~/.bash_profile

Now typing

cats

sends me directly to the folder I need.