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UBC Mathematics: MathNet FAQ [Virtual Server]



UBC Mathematics: MathNet FAQ [Virtual Server]




Question: How to create and use a virtual server?
Author: J. Tam
Date: 2018-06-28

Introduction

A virtual server can be created for a department member's use, and is useful for computational needs that require more resources than the member has, or requires a different operating system than they have access to. It is also useful for developing applications in conjunction with other department members, or requires stable network access.

Only department faculty members can request the creation of a virtual server. Students or visitors who need a virtual server should ask their supervisor to contact the IT staff to create one on their behalf.

Typically, virtual servers will be installed with a version of Unix, such as RedHat or Ubuntu. Other types of OS's can be created but they must be by special requests. The rest of this FAQ assumes that a virtual server with Unix has been installed.

Access to virtual server

Unix virtual servers are typically accessed via ssh command line. This allows users to securely connect to their virtual server from remote networks to issue commands to the virtual server.

Many OSs, including MacOSX, *nix derivatives (e.g. RedHat, Ubuntu, BSD, etc.) have ssh pre-installed, so no additional software is required. Running the ssh client typically starts by opening up a terminal application, and typing

ssh user@vserver.math.ubc.ca
where user is the MathNet username, and vserver is the name of the virtual server assigned to the user.

Windows users can download third-party ssh client software. One popular example of a ssh Windows client is

PuTTY [https://www.putty.org]
Additional archived versions can be found at
MathNet FTP archives [ftp://ftp.math.ubc.ca/clients/Win/Ssh2/]

Displaying graphical output from a virtual server

For some uses, command line version is sufficient, but if the use of an applications that displays graphical output (e.g. Maple, Matlab, desktop GUI, etc.) is required, X-Windows will need to be installed on the laptop or workstations the user is connecting from. This allows graphics output to be display on the local monitor.

The procedure to install X-Windows differs depending on the system it will be installed on:

  1. Unix systems: most have X-Windows pre-installed, so additional software won't be needed. If the system does not have X-Windows, the user can contact the IT staff for help.
  2. MacOSX: an X-Windows system can be downloaded from
    XQuartz [https://www.xquartz.org]
  3. Windows: an X-Windows system can be downloaded from
    VcXsrv [https://sourceforge.net/projects/vcxsrv/]
When starting a ssh session, ssh must be informed that X-Windows is in use: it will allow X-Windows graphical data to be tunnelled back to the local display. For sessions initiated by command-line ssh, an extra -X argument tells ssh to enable X-Windows forwarding e.g.
ssh -X user@vserver.math.ubc.ca
For GUI clients (like PuTTY), X-Windows forwarding can be enabled in the settings menu.

To be written

These are topics that some users have asked about, but have not been written up yet. Please contact the IT staff for more information.

  1. Virtual desktop: x2go
  2. Passwords
  3. Shells
  4. File usage, backup
  5. Firewall policies?