User Interface
The term User Interface, in the context of the Grid, refers to a computer which has the set of user-level (typically Unix command-line) client tools installed on it. There are also APIs in various languages and a number of GUI interfaces are in development, either web-based or as java applications, but at present the main use is via the command line.
Whatever UI you use, your Grid certificate will need to be available there. See the certificate information for more details.
Using a shared UI host
The quickest way to get started is to get an account on an existing UI host. Grid sites will normally have their own UIs, so ask your system administrator about local arrangements. Typically this will either be implemented as a dedicated UI machine that you log in to with your local account, or by mounting the UI commands on all the local Linux machines.
Experiment software
In addition to the standard Grid UI installation there is often a need for access to experiment-specific software. Experiments should provide their own information on how to install it, but one possibility to bear in mind is that this software is often automatically installed on your local Grid site and it may be possible to access it from there, e.g. via an NFS mount, so it's worth discusssing that with your local admin.
In addition to a UI at your local site there may be some general-access UIs available:
lxplus at CERN
People involved with CERN-based experiments (including anyone working directly on the EGEE project) will generally have an account on the lxplus system there, and this can also be used as a Grid UI. Information about getting an account at CERN can be found on their New Users page, although in general this is likely to be handled as part of an induction procedure. There is a wiki page describing how to use lxplus as a Grid UI, but the essential point is simply to source the file
/afs/cern.ch/project/gd/LCG-share/current/external/etc/profile.d/grid-env.shfor Bourne shells or the equivalent .csh file for C shells. There are similar scripts for "new" and "previous" versions of the software to allow for smooth upgrades.
Other experiments
Experiments based at other large laboratories, e.g. DESY, FNAL or SLAC, are also likely to have central computing facilities in a similar way to CERN. Ask your colleagues in the experiment or look at its web pages for further information.
Installing your own UI
For the vast majority of cases it will be preferable to log in to a remote UI. The software is non-trivial to install, and needs ongoing maintenance both in terms of upgrading the middleware itself and in regular updates of the security-related files (CAs and CRLs). The UI needs a network connection anyway to be useful, in which case it should also be possible to ssh to a remote machine.
However, for more adventurous users it is possible to install UIs locally, as long as you have a compatible machine (basically RHEL 3/4 and compatible at present, with Debian and RHEL 5 likely to be supported soon).
CERN AFS UI
By far the simplest solution to getting a UI on your own machine, e.g. a laptop, is to use an AFS client and access the CERN AFS UI described above, i.e. basically source the script:
/afs/cern.ch/project/gd/LCG-share/current/external/etc/profile.d/grid-env.sh
Local UI installation
You can also install the UI software on your own machine as long as it runs a compatible OS, currently Scientific Linux/RHEL or equivalent. This is available either as a user-mode package known as UIPnP or as a full installation using the standard middleware installation tool (YAIM). Bear in mind that for either option you will need to update the software as new releases appear.
Configuration
You will need some configuration information to set up your UI. There may be experiment-specific values in some cases, but in general for UK users it should be safe to use these. The default SE should generally be set to the local SE at your site, or otherwise to a suitable SE that supports your VO. It isn't possible to suggest a completely general default, but the SE below supports a fairly wide range of GridPP VOs. MON_HOST and REG_HOST are only needed if you want to use R-GMA; MON_HOST should normally be the name of your local R-GMA server.
BDII_HOST=lcg-bdii.gridpp.ac.uk MYPROXY_HOST=lcgrbp01.gridpp.rl.ac.uk RB_HOST=lcgrb01.gridpp.rl.ac.uk LB_HOST=lcgrb01.gridpp.rl.ac.uk WMS_HOST=lcgwms01.gridpp.rl.ac.uk REG_HOST=lcgic01.gridpp.rl.ac.uk MON_HOST=lcgmon01.gridpp.rl.ac.uk VO_DEFAULT_SE=heplnx204.pp.rl.ac.uk
Full LCG UI
This is a more complex option, and should only be attempted by people with some experience of administrating a Linux system. You should read the UI tarball installation instructions, and you may also need to refer to the full LCG release documentation. There are also some notes on the installation of a previous version of the UI tarball on this UIG page.
Windows UI
There is a project to provide a UI directly under Windows, see: https://grid.ct.infn.it/twiki/bin/view/GILDA/Grid2WinGUI.
Graphical interfaces
INFNGrid has developed a web-based portal called Genius, although this is not currently in general use in the UK.
There is also a GridPP project called GANGA, which is initially targetted at the Atlas and LHCb experiments but which potentially has a wider application. There is also an intention that GANGA will soon be able to submit jobs via a remote UI, so you would only need to install GANGA on your local machine.
Grid APIs
Many of the Grid middleware components have APIs, typically in C/C++, python and java. However, this is a complex area as the middleware is still under development and the interfaces are changing (in particular most services are migrating towards a web services interface). See the documentation links page for pointers to the detailed documentation for various middleware components, and in particular the main gLite documentation page.
Last modified Mon 7 March 2011 . View page history
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