Login

Questions

  • How to reach UPPMAX clusters?

  • Where do I arrive when I log in? Login or calculation node?

  • What clients should/could I use for my work at UPPMAX?

  • How can I enable graphics?

Objectives

  • We’ll go through platform specific (Mac/Linux/Windows) ways to log in to UPPMAX

  • See different clients

  • Enable graphics

  • Try yourself!

Note

If you lack a user account, visit the Getting started page

The login

General understanding

  • When logging in to UPPMAX from your local computer you will arrive to your home folder at the login node.

  • This means that only light analysis and and calculations should be made here.

  • You will see this in the prompt after “@” as the clustername and a low number. For instance:

       [<user>@rackham3 linux_tutorial]$
    
  • You will later learn how to reach the calculation nodes. Then the prompt states the node number with a single letter, like “r” for Rackham. For instance:

       [<user>@r484 linux_tutorial]
    

Terminals

  • Start terminal (e.g. from Launchpad) or iTerm2

$ ssh <username>@rackham.uppmax.uu.se
  • “< >” prompts you to set the keyword specific for you or your needs. In the example above, this is basically your username.

Terminal

  • iTerm2 goodies:

    • You can save hosts for later.

    • Drag and drop scp

Terminal with X11 server and light graphics

$ ssh -Y <username>@rackham.uppmax.uu.se
  • -X Enables X11 forwarding.

  • -Y Enables trusted X11 forwarding

X11-forwarding from the command line (generally)

  • Graphics can be sent through the SSH connection you’re using to connect

    • Use primarily ssh -Y <...> or secondary ssh -X <...>

  • The X servers that enables graphics are needed, as mentioned above!

    • When starting a graphical program, a new window will open, but your terminal will be “locked”.

    • Run using “&” at the end to run it as a background process e.g. “xeyes &” or “gedit &

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  • Alternatively, use <ctrl>-z to put e.g. gedit to sleep and type “bg” to make last process in background.

Graphical file manager

  • This is good if you want to move many files between host and local and cannot use wildcards.

  • For copying of files with sftp (secure file transfer protocol) between your client computer (where you are) and the cluster Filezilla can be the choice.

  • Filezilla

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Problems with installations?

Putty/Terminal without X11 is sufficient first days of the course!

Linux on your computer

Local Linux environment

  • You may sometimes benefit from having a local Linux environment.

  • Examples:

    • Mimic cluster environment to work with your local files and data as on the Cluster

    • get used to Linux (!)

  • Mac is UNIX and very Linux-like

  • Windows requires WSL (Windows subsystem for Linux)

Visual Studio Code (not covered in course)

ThinLinc (all platforms!)

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Try Thinlinc from web

  • Try the web version now if you don’t already have the software installed!

Keypoints

  • When you log in from your local computer you will always arrive at a login node with limited resources.

  • You reach the calculations nodes from within the login node (See Submitting jobs section)

  • You reach UPPMAX clusters either using a terminal client or Thinlinc

  • Graphics are included in Thinlinc and from terminal if you have enabled X11.

  • Which client to use?

  • Graphics and easy to use

    • ThinLinc

  • Best integrated systems

    • Visual Studio Code has several extensions (remote, SCP, programming IDE:s)

    • Windows: MobaXterm is somewhat easier to use.