Undergraduate Linux: brutha

There is a machine provided for undergraduate use of Linux, and students doing SUPA courses; this is brutha.physics.gla.ac.uk.

There is information below on:

software on brutha
how to connect to brutha
disk quotas
staff users of brutha

Essentially all P&A undergraduates will end up with an account on this system. This account has the same name as your GUID – thus ‘1234567x‘ – and the same password, which you manage on the campus GUID page. We aim to create accounts for all P&A undergraduates at the start of each session, but it's hard to do this reliably, so if you've been missed, you can self-enrol.

Note that as far as brutha is concerned, your GUID must end with a lowercase letter.

Brutha also hosts a JupyterHub notebook server, You can log on to this using the same credentials.

Note:

You should not start long-running programs on this machine: long-running processes will be killed automatically. If you need more substantial compute resources, consult your course convenor or project supervisor.
Do not leave yourself logged in for long periods, when you are not at the machine. Suspending your login session for a reasonable interval is OK; overnight is not.
The general acceptable use policies apply to brutha, of course.

Software on brutha §

Brutha has a ‘normal’ range of software on it, with versions corresponding to the most up-to-date release of CentOS. In particular:

cc: The GCC C compiler
Python: We support Python 3, with a fairly conservative collection of packages installed. Some classes may need more specific Python environments, but these will be managed in consultation with course conveners. There are also some Python 2 binaries and packages on the machine, but we support these only as a side-effect of the Python 3 support. You should generally use Python 3 unless there is a particular circumstance forcing you to use the older version.
LaTeX: there is a standard LaTeX installation, including PDFTeX and XeTeX. If there are packages you need, which are missing, you might consider installing them locally to your account, or ask about having them installed globally if they are likely to be more widely useful.

Connecting to brutha §

Brutha is not accessible from the open internet. To connect, you must either be on campus, or connecting via the VPN or through SSH. The various mechanisms are described in the general login pages.

You can also connect using x2go. This allows you to open a desktop session, which can in principle be suspended and retrieved later. This tends to work, but is sometimes rather fragile in practice. Connecting with ssh and X11 is cruder, but possibly more robust.

Note: although x2go uses the more general NX protocol, it is not compatible with other NX implementations.

ssh: brutha does not examine ssh keys in your home directory. To log in using ssh keys, you must go to the SSO identity page, log in, and add your SSH key where indicated.

Connecting for the first time §

From Session 2018–19: All P&A students have accounts on brutha. All users should have a home directory created, but if you have problems logging in, go to your brutha profile and enter your username. This will show relevant information about your account (most of it copied from the central GUID database). If your home directory is missing (oops), you will see a button at the bottom, which you can press to request that your home directory be created.

Disk quota §

Disk quotas are enabled on brutha – that is, there is a limit to how much disk space you are able to use.

For more information, see the separate information on disk quotas.

Information for staff users of brutha §

A few brief notes for staff, on how brutha is managed:

CentOS, as a Linux distribution, strongly privileges stability – in the sense of mutual compatibility between packages – over up-to-dateness. We're confident enough in this self-consistency that we let our CentOS machines update themselves automatically overnight. This has the downside, however, that sometimes a package version on CentOS will be some way behind what even a cautious user, managing their own laptop, would regard as ‘current’.

Generally, we'll only have on brutha software which comes as a CentOS package. There are exceptions, but they are case-by-case and reluctant.

Python libraries: The place where this is most likely to affect you is in the matter of Python libraries. Generally, if a Python library is available as a CentOS package (and many are), we'll install it into the default Python on request, and you can use this confident that there's a relatively low probability of this conflicting with other Python libraries.

If a library is not available as a CentOS package, then we will typically not make it available in the default Python. There is however a small number of Python ‘virtualenvs’ maintained for various purposes, with a broader range of packages. These correspond to the different ‘kernels’ visible on JupyterHub. If you need packages which aren't available in the default python, they might be available in, or can be added to, one of these virtualenvs. Discuss your requirements with Norman or Sandy.

(Python virtualenvs are a Good Thing, by the way, and if you are managing Python libraries on a non-brutha machine, you might want to consult our vitualenv notes in the list of tips.)

Similarly, if you absolutely need a more recent version of, say, Python or GCC than is available on brutha then it should be possible to organise this in manageable way. Talk to Norman.

Graphics, A side-note: brutha doesn't have a GPU attached, so packages which off-load graphical work to a GPU will generally be disappointing when used via JupyterHub.

phas-brutha list: There is a low volume email list for those staff with an interest in brutha; it's intended for announcements and possible discussion of policy. Join the phas_brutha list for updates.