Noctua

Quick Links:

Noctua Hardware Overview

pc2status on Noctua

File Systems on Noctua

Workload-Manager on Noctua

Available Software on Noctua

Tuning Hints for Noctua

Noctua FPGA Usage

FAQ

The Noctua cluster

Details about the hardware architecture of Noctua can be found at the PC² website. The current status and upcoming-events related to the Noctua system can be found at the main page of this wiki.

Noctua is the first phase of the Noctua-project and will be extended 2020/2021 by the second phase.

Please note, that you can only log in to Noctua if you are a member of a project that has been granted computing time on the Noctua cluster by the resource allocation board. If you are not yet a member of an accepted project you can:

• ask the project administrator of an accepted project to add you as a user
• or submit a proposal for computing time. Please follow the instructions at [1].

How to access Noctua

Noctua uses a "jump host" as a load balancer

fe.noctua.pc2.uni-paderborn.de

From fe.noctua.pc2.uni-paderborn.de you can then establish an ssh-connection to one of the two physical frontends of Noctua.

For the authentication, you can

• use password-based or ssh-key-based authentication as a user from Paderborn University.
  • We recommend ssh-key-based authentication with password-protected ssh-keys.
• As an external user, you can only use ssh-key-based authentication due to security considerations.
  • If you have not yet deposited a key, please send us the public key of your SSH keyring to pc2-support@uni-paderborn.de. We can then install it for you.

Instruction on how to create an ssh-key can be found at [2]. Only keys that are password-protected are allowed to be used in the context of PC² cluster systems.

Interactive Sessions

We recommend the following combined command for an interactive session:

   ssh -t fe.noctua.pc2.uni-paderborn.de ssh noctua

Alternatively, you can put

   Host noctua
   HostName fe.noctua.pc2.uni-paderborn.de
   User [USERNAME]
   RequestTTY force
   IdentityFile [PATH TO PRIVATE KEY]
   IdentitiesOnly yes
   RemoteCommand ssh noctua

in your ~/.ssh/config and replace [USERNAME] with your username on Noctua and [PATH TO PRIVATE KEY] with the path to your private key of your ssh-key. Then you can use the short command ssh noctua to connect to Noctua. You will be asked for the password of your ssh-key when logging in instead of your user password.

If you want to connect to the last connected frontend, then use this command:

  ssh -t fe.noctua.pc2.uni-paderborn.de ssh noctua-last

If you need to a run graphical application, the -X option should be used, which enables X11 forwarding with X11 SECURITY extension. The complete command is

   ssh -X -t fe.noctua.pc2.uni-paderborn.de ssh -X noctua

Further information for accessing Noctua by using SSH public key authentication can be found here.

Access for Programs

For programs like Visual Studio Code [3] that support remote development via ssh, you need a different ssh-config to deal with the load-balancer. You can add the following blocks to your ssh-config:

Host noctua-jumphost
  Hostname fe.noctua.pc2.uni-paderborn.de
  User [USERNAME]
  IdentityFile [PATH TO PRIVATE KEY]
  IdentitiesOnly yes

Host noctua-ln1
  Hostname ln-0001
  User [USERNAME]
  ProxyJump noctua-jumphost
  IdentityFile [PATH TO PRIVATE KEY]
  IdentitiesOnly yes

Host noctua-ln2
  Hostname ln-0002
  User [USERNAME]
  ProxyJump noctua-jumphost
  IdentityFile [PATH TO PRIVATE KEY]
  IdentitiesOnly yes

This will instruct ssh to use the host noctua-jumphost as a proxy when trying to connect to one of the frontends noctua-ln1 or noctua-ln2. We recommend to explicitly choose a frontend here because programs like Visual Studio Code run a daemon on the remote host and by explicitly choosing a frontend you avoid issues if you want to use multiple program instances. In programs like Visual Studio Code you can then simply select to ssh configuration noctua-ln1 or noctua-ln2 to connect to. Please don't use this way for interactive sessions.

First Steps on Noctua

After you have successfully logged in to Noctua we recommend you to:

• Try out pc2status. This command-line tool gives you an overview of the projects you are a member of, the used computing times, monthly contingents, and file system quotas.
• Get familiar with Slurm which is the workload manager used on Noctua because you need it to do computations on the cluster.
• Have a look at the software already available on Noctua.

If some questions or problems come up, please consult the FAQ or ask us by mail at pc2-support@uni-paderborn.de.