Background

IRIS is a national e-Infrastructure project that is funded to provide computing hardware infrastructure for astronomy and particle physics projects. The funding has been allocated to a number of existing high-performance computing (hpc) sites., providing a variety of platforms including:

• HPC – for traditional high-performance simulation and data analysis (via DiRAC)

• Grid – for massive-scale high-throughput computing (via GridPP)

• Cloud – for interactive computing (e.g. Jupyter Notebooks) and project-related services (via Scientific OpenStack at Cambridge, Manchester, and RAL, plus possibly others).

These three infrastructures support different use cases and different access mechanisms. At the time of writing, they are effectively separate infrastructures, which are accessed using different approaches, discussed in turn below.

IRIS resources are allocated to project groups (such as LSST:UK) on an annual basis, with allocations running during April--March. A list of previous and active LSST:UK awards is provided below.

IRIS HPC Infrastructure

HPC resources are provided to IRIS by Cambridge, on a machine called CSD3, though administered via another national project called DiRAC.

DiRAC uses a system called SAFE (Service Administration, from EPCC) to manage account creation, authorisation and resource tracking.

Getting Access

To access IRIS/ DiRAC infrastructure, hosted at Cambridge, you need to complete two steps:

1. (If you don’t already have one) you need a DiRAC SAFE account.

   1. To register with SAFE you need to fill in the web form here: https://safe.epcc.ed.ac.uk/dirac/

   2. There is am email-verification step required to complete registration

2. You need to request a login account for the DiRAC Cambridge system, via the SAFE web interface, and have your login account associated to the LSST:UK project award on DiRAC. Specify the following values, when asked:

   1. Project code: ip005

   2. IP range: 131.111.0.0/16

Further useful instructions are available from DiRAC:

• https://dirac-safe.readthedocs.io/en/latest/safe-guide-users.html

N.B. If you are a Cambridge user and wish to use your existing computing-service account, you may apply for access via a University-local approach detailed here.

Useful tips

Lots of useful tips for getting the most out of the LSST:UK time on DiRAC @ Cambridge are available at:

https://docs.google.com/document/d/1OO3h8X6J8v63VcE49RnzcuuqyNNnHIw6fQMJk8zXJ6I/edit#heading=h.77zddaybe5pt

In particular, you can check the current balance of compute time, with a command such as:

$ gbalance -p iris-ip005-cpu

—and check individual usage with a command such as:

$ sreport -t Hours cluster AccountUtilizationByUser cluster="csd3" \

start=2021-04-01T00:00:00 end=now accounts=iris-ip005-cpu format=Account,Login,Used

IRIS Grid Infrastructure

Skeleton instructions to be expanded.

To use the IRIS grid infrastructure resources that have been allocated to the project, you first need to obtain an X.509 grid certificate (e.g., if you are a UK academic, you can obtain a certificate by following the instructions at https://ca.grid-support.ac.uk/), which you will use to authenticate with UK (and other) grid computing resources.

N.B. Obtaining a Grid certificate is a relatively complicated process, which will likely take several weeks to complete. If you are not already familiar with handling X.509, you should read your preferred Certificate Authority’s guidance carefully to ensure a smooth application process.

Having obtained your X.509 certificate, you need to request to join the LSST Virtual Organisation (VO). You do this by visiting the VO’s management site at https://voms.slac.stanford.edu:8443/voms/lsst/user/home.action, though you first need to import your certificate into your web browser.

You should be taken to the registration page, from which you can request to join the LSST VO. Again, it may take several days for your registration request to be processed.

Once you have your X.509 certificate registered for the LSST VO, you can begin to experiment with some of the basic grid tools to gain experience of grid computing. Information on how to do this is available via the GridPP website, www.gridpp.ac.uk though note that some of the document is known to be old or incomplete.

IRIS Cloud Infrastructure

To be documented

LSST:UK Awards on IRIS

Document History

??/??/??? – Initial version developed by @Richard McMahon

4/OCT/19 – Ported to Confluence and extended by @George Beckett