Exercises: Accessing LUMI

See the instructions to set up for the exercises.

1. Log on to an arbitrary login node of LUMI.

   Can you find how to check your quota and status of your allocation?

   Click to see the solution.

   How to check your quota and status of your allocation, is explained in the message-of-the-day at the bottom of the "Announcements" section: you can use the lumi-workspaces command.

   The lumi-workspaces command uses Lustre commands to check the quota in real-time. It will however get stuck if one of the Lustre filesystems used by your project or user account, is unavailable. In that case we still have the lumi-ldap-userinfo and lumi-ldap-projectinfo commands. Don't try to understand all output of those commands. They are meant to be used by the LUMI User Support Team in the first place. However, it does show the last stored quota. But it can take a while after, e.g., deleting files before that shows up in this data (typically up to one hour, but longer in case of technical problems on the system which you may not always notice).

2. How can you log on to a specific login node of LUMI, e.g., the login node "uan01"?

   Click to see the solution.

   To log in to the login node "uan01", use the hostname lumi-uan01.csc.fi instead of lumi.csc.fi.

   This may be useful if you use software on your desktop that tries to connect repeatedly to LUMI and then tries to find, e.g., a running server that it created before.

3. Create a shell on a login node using the Open OnDemand web interface?

   Click to see the solution.

   • Point your web browser to https://www.lumi.csc.fi. With some browsers it is sufficient to type lumi.csc.fi in the address bar while others require www.lumi.csc.fi.
   • Click the "Go to login" button. What you need to do here, depends on how you got your account. For the course you will have to proceed with the "MyAccessID" option "Login Puhuri" in most cases.

   • Once you're in the web interface, click on "Login node shell" (likely the third choice on the first line). It will open a new tab in the browser with a login shell on LUMI. Note that Open OnDemand uses a different set of login nodes.

     The "Login node shell" app does not require billing units, but has the same restrictions on use as the regular login nodes. It should not be used for heavy computations. The "Compute node shell" app will give you an interactive shell on a specific set of compute nodes set aside for interactive use, but will be charged to your billing units. It will give you exclusive access to a number of cores and associated memory. The "Desktop" app gives you a richer environment, but will also require billing units. Depending on the type of node that you use for this, this will require either CPU or GPU billing units, but more about that in the session on Slurm on day 2 of this course.

4. Try to transfer a file from your desktop/laptop to your home directory via the Open OnDemand web interface.

   Click to see the solution.

   • Go back into Open OnDemand if you have left it after the previous exercise.
   • On the main screen of the web interface, choose "Home directory".
   • Depending on the browser and your system you may be able to just drag-and-drop files into the frame that shows your files, or you can click the blue "Upload" button towards the top of the screen.