Overview

Teaching: 45 min
Exercises: 15 min

Questions

• How to connect without using passwords?

Objectives

• Learn how to connect to Spruce in several ways

ssh

Currently WVU has two clusters for HPC, mountaineer and spruce. You can access them using SSH. SSH provides a secure channel over an unsecured network such as internet. Both Linux and macOS commonly include the SSH client by default. On Windows machines you can use a free application called PuTTY or MobaXTerm.

To connect to Mountaineer use:

ssh <username>@mountaineer.hpc.wvu.edu

For Spruce

ssh <username>@spruce.hpc.wvu.edu

Once you enter on the system, you can start typing commands. You can open several connections simultaneously. Each connection is independent of each other.

tmux

Power users can benefit from a terminal multiplexer such as tmux. tmux is a terminal multiplexer. It lets you switch easily between several programs in one terminal, detach them (they keep running in the background) and reattach them to a different terminal.

tmux allows users to keep several virtual windows and panels open from a single connection. It offers also preserve the terminal status in case of disconnection from the server.

To use tmux, first connect to the server and execute the command

tmux

You can create new virtual windows with CTRL-b c, you move between windows with CTRL-b n and CTRL-b p. You can detach from your multiplexed terminals with CTRL-b d.

If for some reason you lost the connection to the server or you detached from the multiplexer all that you have to do to reconnect is to execute the command:

tmux a

In tmux, hit the prefix CTRL+b and then:

Sessions

    :new<CR>  new session
    s  list sessions
    $  name session

Windows (tabs)

    c  create window
    w  list windows
    n  next window
    p  previous window
    f  find window
    ,  name window
    &  kill window

Panes (splits)

    %  vertical split
    "  horizontal split
    o  swap panes
    q  show pane numbers
    x  kill pane
    +  break pane into window (e.g. to select text by mouse to copy)
    -  restore pane from window
    ⍽  space - toggle between layouts
    q (Show pane numbers, when the numbers show up type the key to goto that pane)
    { (Move the current pane left)
    } (Move the current pane right)
    z toggle pane zoom

Copy model

    [  Copy mode

Others

    d  detach
    t  big clock
    ?  list shortcuts
    :  prompt

Key Points

• Use ssh to connect to Spruce

• On windows you can use PuTTY

• To get X Window on Windows use for example MobaXTerm