University of Bath

Research Computing Team (DDaT)

Anatra HPC Documentation

Accessing Anatra

Overview:

  • Teaching: 10 min
  • Exercises: 0 min

Questions

  • How do I access Anatra?
  • Where do I find out more information about ssh and security?

Objectives

  • Understand what ssh is, and securing your connection
  • Be able to log-on to Anatra

SSH

As HPC services are remote machines, interaction is done over an encrypted communication channel called Secure Shell version 2 (SSH-2). This allows command-line access to one of the login nodes of a HPC service, from which you can run commands or use a command-line text editor to edit files.

Security

Users and system operators have a shared responsibility to ensure the security of resources. System operators monitor the system, ensure security patches are up-to-date and that the systems is configured to restrict access correctly e.g. so that users cannot see each others data/files by default.

Users should follow best practice to mitigate the risk of accounts and access details being compromised, e.g. we all know that we must keep our passwords secret. You shouldn't make your files accessible to others unless necessary.

Strong passwords

A strong password describes a password that is difficult to detect by both humans and computer programs, effectively protecting data from unauthorized access. A strong password consists of at least twelve characters (and the more characters, the stronger the password) that are a combination of letters, numbers and symbols (@, !, &, ^ etc) if allowed. Passwords are typically case-sensitive, so a strong password contains letters in both uppercase and lowercase. Strong passwords also do not contain words that can be found in a dictionary or parts of the user's own name.

SSH key pairs

As with Balena, we do not currently support authentication via key pairs.

More details on ssh and security

For further details on ssh, and security you can visit the ARC lesson:

https://arc-lessons.github.io/security/00_schedule.html

Logging onto the University Linux service

The cloud HPC service can only be accessed either on campus or from behind the University VPN. For details on accessing the VPN you can visit https://www.bath.ac.uk/guides/setting-up-vpn-on-your-device/.

An alternative is to go through the University linux service (which is what we shall do here - but if behind the VPN you can jump staight to logging onto the cloud HPC service).

Let's try logging on to the University linux service. (For a more in depth description visit our guide on how to login).

You can log-in to linux.bath.ac.uk with you University username and password using the following command from the terminal window:

ssh [userID]@linux.bath.ac.uk

Insert your University credentials and you should be greeted with the following log-in message:

This is a service for Staff and Students of the
University of Bath.

Disconnect NOW if you have not been expressly authorised
to use this system.

Unauthorised use is a criminal offence under the Computer
Misuse Act 1990.

Communications on or through the University of Bath
computer systems may be monitored or recorded to secure
effective system operation and for other lawful purposes.

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( |_||_||_| |_| \__,_|/_/\_\ .bath.ac.uk )
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       ▓▓▓▓▓
 ▓▓▓ ▓▓▓▓▓▓▓▓▓ ▓▓▓  OS:     Ubuntu 18.04.6 LTS
 ▓ ▓░░░▓▓▓▓▓▓▓▓▓ ▓  Codename:   Bionic Beaver
  ▓░░░░░▓▓▓▓▓▓▓▓▓   Kernel: 4.15.0-166-generic
 ░░░██░░▓▓▓▓▓2 ▓▓▓  Hostname:   linux2.bath.ac.uk
 ░░░░░░▓▓▓▓▓▓▓▓▓▓▓  Cores:  4 @ 2.14 GHz
 ▓▓▓▓▓       ▓▓▓▓▓  CPU:    Intel(R) Xeon(R) E5-2660
  ▓▓▓▓▓▓   ▓▓▓▓▓▓   RAM:    16 GB
   ▓▓▓▓██║██▓▓▓▓    Users:  2
     ▓▓██║██▓▓
       ██║██


---------------------------------------------------------
Run the command software to see what is available
---------------------------------------------------------
Issues or requests goto - http://go.bath.ac.uk/helpform
---------------------------------------------------------
Linux® is the registered trademark of Linus Torvalds
---------------------------------------------------------
Last login: Fri Dec 10 12:33:23 2021 from 172.25.63.115

mjc62 in linux2 in ~

Logging onto the Anatra HPC service

Now we are on the University linux service (or behind the University's VPN) we can try logging onto the new Anatra HPC environment.

ssh [userID]@anatra.bath.ac.uk

You should be greeted with the Anatra login:

_                _
   / \   _ __   __ _| |_ _ __ __ _
  / _ \ | '_ \ / _` | __| '__/ _` |
 / ___ \| | | | (_| | |_| | | (_| |
/_/   \_\_| |_|\__,_|\__|_|  \__,_|

-------------------------------------------------------------------------------
Use the following commands to adjust your environment:

'module avail'            - show available modules
'module add <module>'     - adds a module to your environment for this session
'module initadd <module>' - configure module to be loaded at every login

-------------------------------------------------------------------------------

Last login: Sun Jan 23 15:50:37 2022 from 138.38.3.37

[bad45@loginnode1 ~]$
❯

To achieve the above in a single command, linux.bath.ac.uk can be invoked as a JumpHost:

ssh -J [userID]@linux.bath.ac.uk [userID]@anatra.bath.ac.uk

Congratulations! You're now logged in to Anatra!!

On Campus

It is possible to log onto the University linux service from a University PC with:

  • ‘Start’ → All Programs → Xming → linux

This launches a program called ‘Kitty’ which will try to connect to the linux service. A window should open which asks for login as:. Insert your University username, and you will be prompted for a password:

linux-password

If you have successfully logged on, the window will display the same University Linux welcome message above.

The process for accessing Anatra from this session is the same as above.

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