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Start interactive session

Learning objectives

  • Practice using the UPPMAX documentation
  • Understand what an interactive session is
  • Can start an interactive session
  • Can conclude being on a login or compute node
  • Can end an interactive session
For teachers

Teaching goals are:

  • Learners have practiced using the UPPMAX documentation
  • Learners understand what an interactive session is
  • Learners can start an interactive session
  • Learners can conclude being on a login or compute node
  • Learners can end an interactive session

Lesson plan:

gantt
  title Start an interactive session
  dateFormat X
  axisFormat %s
  section First hour
  Prior : prior, 0, 5s
  Present: present, after prior, 2s
  %% It took me 7 mins, here I do that time x2
  Challenge: crit, challenge, after present, 14s
  %% Here I use the same time it took me to give feedback
  Feedback: feedback, after challenge, 7s

Prior questions:

  • What is an interactive session?
  • Why use an interactive session?
  • When scheduling an interactive session, what does the job scheduler need to know?
  • How to stop an interactive session?

Why?

Login nodes are used interactively for light processes, e.g. submitting a job. However, sometimes one needs to do harder things interactively, e.g. running an IDE.

In this session, we learn how to start an interactive session.

Exercises

Need a video?

Here is a video that shows the solution of these exercises

Exercise 1: start and end an interactive session on Rackham

Go to the UPPMAX documentation at https://docs.uppmax.uu.se, then answer these questions:

  • Find the page on how to start an interactive session on Rackham
Answer

It can be found at https://docs.uppmax.uu.se/cluster_guides/start_interactive_node_on_rackham/

  • Start an interactive session on Rackham that lasts one hour
Answer

You can do so ike this:

interactive -A uppmax2023-2-25 -t 1:00:00
  • How do you know you are no longer on the login node?
Answer

There are multiple ways. The easiest is to look at the prompt: it has changed from @rackham[1-4] to @r[1-5000], which means you are on a Rackham compute node

  • Stop the interactive session
Answer

You can do so like this:

exit
  • How do you know you are on the login node again?
Answer

There are multiple ways. The easiest is to look at the prompt: it has changed from @r[1-5000] to @rackham[1-4], which means you are on a Rackham login node

  • (optional) Start an interactive session on Rackham that lasts one hour and uses two cores. This is recommended when using RStudio on Rackham
Answer

You can do so ike this:

interactive -A uppmax2023-2-25 -t 1:00:00 -n 2