Accessing BlueBEAR

Access to BlueBEAR is gained by logging on to one of the login nodes of the cluster. For the security of the service, access is limited to machines on the campus network.  The University provides a Remote Access Service which allows you to be able to connect to BlueBEAR remotely.

Access to BlueBEAR

There are two steps to gaining access to BlueBEAR:

  1. being registered on a BEAR project that has access to the BlueBEAR service;
  2. have an active BEAR Linux account.

Usernames

All usernames on BlueBEAR are lower case; thus, abc123 is a valid username whereas ABC123 is not.

Login Nodes

BlueBEAR has multiple login nodes which are allocated in a round-robin fashion. These are available from the address

bluebear.bham.ac.uk

These nodes are meant for tasks such as submitting batch jobs, checking on job status, editing, and performing simple tasks.

Login nodes must not be used for work requiring significant CPU resources, including analysis jobs running from a Graphical User Interface (GUI) such as those provided by some engineering or Computational Fluid Dynamics (CFD) codes. Jobs requiring significant CPU, or multiple cores, should be run in the batch system. Those wishing to run GUI applications should do so in the BlueBEAR Portal or through an interactive job.

Any work that is consuming significant CPU on a login node, or causing problems such as poor responsiveness of the login nodes for other users, may be stopped without warning.

Windows software to access BlueBEAR

The PuTTY secure shell client, which provides text-based access to the system, is required to access the system. Graphical support is available using Exceed, which is available on site license from software sales.

PuTTY only provides command-line access to the cluster; for graphical support Exceed is required. In addition, Exceed3D is required for applications that require OpenGL support on the Windows desktop; Exceed3D is also available on site license from software sales. The setup of PuTTY differs depending on whether or not Exceed is being used.

See the help page for installing and configuring PuTTY and Exceed for detailed information about obtaining, installing and configuring PuTTY and optionally Exceed/Exceed3D.

Accessing BlueBEAR using the command line

To access BlueBEAR using command-line ssh, for example from Linux or Mac, use this command in your terminal (replacing 'username' with your username):

ssh username@bluebear.bham.ac.uk

This may require configuration to add or remove keys from the known hosts file; since this depends on the version of the operating system that is being run the details cannot be documented on this help page.

Accessing BlueBEAR using the BlueBEAR Portal

The BlueBEAR Portal provides web-based access to a range of BlueBEAR services, such as JupyterLab, RStudio, and some GUI applications. It also provides access for submitting BlueBEAR compute jobs. The BlueBEAR Portal is only available from on-campus or through using the University Remote Access Service.

Resumable Sessions

Please be aware that if you lose connection whilst working interactively on a node then your session (and potentially work) will also be lost. To mitigate this issue we would recommend running in either a tmux or screen session, which will remain active after you disconnect from the node. This method will only work for non-graphical applications.

To create either a tmux or screen session please issue one of the following commands:

$ tmux new-session -s session1
$ screen -S session1

To re-attach to an exisiting session (for example, following a forced disconnect) issue one of the following:

$ tmux attach -t session1
$ screen -r session1

Note that you can name the sessions as you please – session1 is just an example.
Further information on both of these applications can be found online. In general we would recommend tmux as it has a richer feature-set and more detailed usage information can be found here.

Fix Login

There are several files that are run by default when logging on or off. If these become corrupted or deleted a login session will be in an unpredictable state; a typical example of this happening is a non-standard command prompt. If this happens the default files can be restored using the command

fixlogin

which will warn if any existing, and possibly corrupt, files are to be overwritten. To restore the default files without being prompted use the command

fixlogin -y

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