1. Oxford University Particle Physics Unix Overview
Sunday, 24 February 2019
Oxford University Particle Physics Unix Overview
Sean Brisbane
Particle Physics Systems Administrator
Room 661
Tel 73389
14th October 2015
Graduate Lectures

2. Local Cluster Overview Connecting to it Grid Cluster Computer Rooms
Strategy
Local Cluster Overview
Connecting to it
Grid Cluster
Computer Rooms
How to get help
Graduate Lectures
14th October 2014

3. Particle Physics Strategy The Server / Desktop Divide
Sunday, 24 February 2019
Particle Physics Strategy The Server / Desktop Divide
Virtual Machine Host
Servers
General Purpose Unix Server
Linux Worker nodes
Group DAQ Systems
Linux File Servers
Web Server
NIS Server
torque Server
Win 7 PC
Win 7 PC
Ubuntu PC
laptop
Linux Desktop
Clients
Users should use exceed from their windows 2000 desktop pc’s to connect to unix servers.
Do not store files on the desktop they are not backed up.
The servers home areas are backed up.
Graduate Lectures
14th October 2014

4. Distributed Model
Files are not stored on the machine you are using, but on remote locations You can run a different operating system by making a remote connection to it
Graduate Lectures
14th October 2014

5. Recommended working strategy
Computing work splits broadly into
Office work (local/remote)
Writing code (remote)
Computation (remote)
Use your favourite desktop/laptop for office files.
Make a remote desktop connection to pplxint8/9 to do computing work on the batch farm
It is better to write code on the remote Linux desktop
Graduate Lectures
14th October 2014

6. Physics Remote desktops
We use RDP for remote desktop
This means that everyone in particle physics has access to multiple desktop environments from anywhere
Windows (termserv.physics.ox.ac.uk)
Scientific Linux (pplxint8/9)
Ubuntu Linux (ubuntu-trusty-ts)
MaxOSX (osxts via vnc)
Graduate Lectures
14th October 2014

7. /data/home, /data/experiment
Storage
Physics storage
Windows server
Central Linux file-server
Storage system:
PP file-server
Client
Windows
Central Ubuntu
PP Linux
Recommended storage
H:\ drive
/home folder
/home and /data folders
Windows storage
“H:\” drive or “Y:\home”
/physics/home
PP Storage
Y:/LinuxUsers/pplinux/data/home
/data/home, /data/experiment
Central Linux
Y:/LinuxUsers/home/particle
/network/home/particle
Graduate Lectures
14th October 2014

8. To store files on servers using your laptop
Windows: map your H:\ drive by typing
net use H password /USER:yourname
- Where yourname is your physics user name
OSX:
Linux:
Graduate Lectures
14th October 2014

9. RDP and storage demo H:\ drive on windows
Connecting to Linux on pplxint8 from windows
/home and /data on Linux
Graduate Lectures
14th October 2014

10. Particle Physics Linux
Unix Team (Room 661):
Sean Brisbane – Local Server and User Support
Kashif Mohammad – Grid and Local Support
Ewan MacMahon – Grid Systems Administrator
Pete Gronbech - Senior Systems Manager and GridPP Project Manager
General purpose interactive Linux based systems for code development, short tests and access to Linux based office applications. These are accessed remotely.
Batch queues are provided for longer and intensive jobs. Provisioned to meet peak demand and give a fast turnaround for final analysis.
Our Local Systems run Scientific Linux (SL) which is a free Red Hat Enterprise based distribution.
The same as the Grid and CERN
We will be able to offer you the most help running your code on SL6.
Graduate Lectures
14th October 2014

11. Current Clusters Particle Physics Local Batch cluster
Oxford’s Tier 2 Grid cluster
Graduate Lectures
14th October 2014

12. PP Linux Batch Farm Scientific Linux 6
Users log in to the interactive nodes
pplxint8 & 9, the home directories and all the data disks (/home area or /data/group ) are shared across the cluster and visible on the interactive machines and all the batch system worker nodes.
Approximately 600 cores (430 incl. JAI/LWFA), each with 4GB of RAM memory.
The /home area is where you should keep your important text files such as source code, papers and thesis
The /data/ area is where you should put your big reproducible input and output data
jailxwn02
64 * AMD cores
jailxwn01
64 * AMD cores
pplxwn68
16 * Intel cores
pplxwn67
16 * Intel cores
pplxwnnn
16 * Intel 2650 cores
pplxwn41
16 * Intel 2650 cores
pplxwn32
12 * Intel 5650 cores
pplxwn31
12 * Intel 5650 cores
pplxdatatrans
Grid data transfer nodes
pplxint9
Interactive login nodes
pplxint8
Graduate Lectures
14th October 2014

13. NFS and lustre storage Servers
PP Linux Batch Farm
Data Storage
NFS and lustre storage Servers
40TB
The /data areas are big and fast disks. This is too big to be backed-up but still have some redundancy features and are safer than laptop storage. This does not help if you delete files.
Data Areas
pplxfsn
40TB
Data Areas
The /home areas are backed up by two different systems nightly.
The latest nightly backup of any lost or deleted files from your home directory is available at the read-only location /data/homebackup/{username}
If you need older files, tell us
If you need more space on /home, tell us
Store your thesis on /home NOT /data.
pplxfsn
30TB
Data Areas
pplxfsn
19TB
Home areas
pplxfsn
Graduate Lectures
14th October 2014

14. Two Computer Rooms provide excellent infrastructure for the future
The New Computer room built at Begbroke Science Park jointly for the Oxford Super Computer and the Physics department, provides space for 55 (11KW) computer racks. 22 of which will be for Physics. Up to a third of these can be used for the Tier 2 centre. This £1.5M project was funded by SRIF and a contribution of ~£200K from Oxford Physics.
The room was ready in December Oxford Tier 2 Grid cluster was moved there during spring All new Physics High Performance Clusters will be installed here.
Graduate Lectures
14th October 2014

15. Graduate Lectures
14th October 2014

16. Local Oxford DWB Physics Infrastructure Computer Room
Completely separate from the Begbroke Science park a computer room with 100KW cooling and >200KW power has been built. ~£150K Oxford Physics money.
Local Physics department Infrastructure computer room.
Completed September 2007.
This allowed local computer rooms to be refurbished as offices again and racks that were in unsuitable locations to be re housed.
Graduate Lectures
14th October 2014

17. Graduate Lectures
14th October 2014

18. Strong Passwords etc
Use a strong password not open to dictionary attack!
fred123 – No good
Uaspnotda!09 – Much better
More convenient to use ssh with a passphrased key stored on your desktop.
Once set up
Graduate Lectures
14th October 2014

19. Connecting with PuTTY to Linux
Demo
Plain ssh terminal connection
From ‘outside of physics’
From Office (no password)
ssh with X windows tunnelled to passive exceed. Single apps.
Password-less access from ‘outside physics’
Graduate Lectures
14th October 2014

20. Graduate Lectures
14th October 2014

21. Other resources (for free)
Oxford Advanced Research Computing
A shared cluster of CPU nodes, “just” like the local cluster here
GPU nodes
Faster for ‘fitting’, toy studies and MC generation
*IFF* code is written in a way that supports them
Moderate disk space allowance per experiment (<5TB)
The Grid
Massive globally connected computer farm
For big computing projects
Atlas, LHCb, t2k and SNO please stay at the end!
Come talk to us in RM 661 about these
Graduate Lectures
14th October 2014

22. The end of the overview Now more details of use of the clusters
Help Pages
ARC
GRID talk at the end
Graduate Lectures
14th October 2014

23. Atlas, Sno, LHCb and t2k please read this
GRID certificates
Atlas, Sno, LHCb and t2k please read this
Graduate Lectures
14th October 2015

24. SouthGrid Member Institutions
Oxford
RAL PPD
Cambridge
Birmingham
Bristol
Sussex
JET at Culham
Graduate Lectures
14th October 2014

25. Current capacity Compute Servers Storage Twin and twin squared nodes
1770 CPU cores
Storage
Total of ~1300TB
The servers have between 12 and 36 disks, the more recent ones are 4TB capacity each. These use hardware RAID and UPS to provide resilience.
Graduate Lectures
14th October 2014

26. Get a Grid Certificate http://www.ngs.ac.uk/ukca
You will then need to contact central Oxford IT. They will need to see you, with your university card, to approve your request:
To:
Dear Stuart Robeson and Jackie Hewitt,
I Please let me know a good time to come over to Banbury road IT office for you to approve my grid certificate request.
Thanks.
Get a Grid Certificate
Must remember to use the same PC to request and retrieve the Grid Certificate.
The new UKCA page
uses a JAVA based CERT WIZARD
Graduate Lectures
14th October 2014

27. When you have your grid certificate…
Log in to pplxint9 and run mkdir .globus chmod 700 .globus cd .globus openssl pkcs12 -in ../mycert.p12 -clcerts -nokeys -out usercert.pem openssl pkcs12 -in ../mycert.p12 -nocerts -out userkey.pem chmod 400 userkey.pem chmod 444 usercert.pem
Save to a filename in your home directory on the Linux systems, eg:
Y:\Linuxusers\particle\home\{username}\mycert.p12
14th October 2014
Graduate Lectures

28. Now Join a VO This is the Virtual Organisation such as “Atlas”, so:
You are allowed to submit jobs using the infrastructure of the experiment
Access data for the experiment
Speak to your colleagues on the experiment about this. It is a different process for every experiment!
Graduate Lectures
14th October 2014

29. Joining a VO
Your grid certificate identifies you to the grid as an individual user, but it's not enough on its own to allow you to run jobs; you also need to join a Virtual Organisation (VO).
These are essentially just user groups, typically one per experiment, and individual grid sites can choose to support (or not) work by users of a particular VO.
Most sites support the four LHC VOs, fewer support the smaller experiments.
The sign-up procedures vary from VO to VO, UK ones typically require a manual approval step, LHC ones require an active CERN account.
For anyone that's interested in using the grid, but is not working on an experiment with an existing VO, we have a local VO we can use to get you started.
Graduate Lectures
14th October 2014

30. When that’s done Test your grid certificate:
> voms-proxy-init –voms lhcb.cern.ch
Enter GRID pass phrase:
Your identity: /C=UK/O=eScience/OU=Oxford/L=OeSC/CN=j bloggs
Creating temporary proxy Done
Consult the documentation provided by your experiment for ‘their’ way to submit and manage grid jobs
Graduate Lectures
14th October 2014

31. BACKUP
Graduate Lectures
14th October 2014

32. Puttygen to create an ssh key on Windows (previous slide point #4)
Sunday, 24 February 2019
Puttygen to create an ssh key on Windows (previous slide point #4)
Paste this into ~/.ssh/authorized_keys on pplxint
Enter a secure passphrase then :
- Enter a strong passphrase
- Save the private parts of the key to a subdirectory of your local drive.
If you are likely to then hop to other nodes add :
ForwardAgent yes
to a file called config in the .ssh dir on pplxint
Graduate Lectures
14th October 2014

33. Pageant Run Pageant once after login
Right-click on the pageant symbol and and “Add key” for your Private (windows ssh key)
Graduate Lectures
14th October 2014