Getting a remote desktop on ALICE or SHARK with X2Go

X2Go (External Link) allows you to interact with ALICE or SHARK through a graphical desktop instead of the command line interface. For some applications, using X2Go can be more efficient than running X11 forwarding. X2Go is available for Windows, MacOS and various Linux flavors.

This page shows how to setup and make use of X2Go on ALICE and SHARK.

Getting X2Go

The X2Go client can be downloaded from the X2Go homepage (External Link) and installation instructions are available here (External Link).

  • For Linux, x2go is available through the standard package manager of several distributions, e.g.,

    • CentOS/Fedora/Red Hat: yum install x2goclient

    • Ubuntu/Debian: apt-get install x2goclient

    • Arch Linux: pacman -S x2goclient

  • For Windows, you can choose between a Windows installer or a portable version

  • For MacOS, you can choose between installer for different versions of MacOS

You do not need the X2Go server.

Setting up the connection

If you have installed the X2Go client, you can set it up for ALICE or SHARK:

 

ALICE

SHARK

 

ALICE

SHARK

Start X2Go, select “Session” in the menu and then “New Session”.

Start X2Go, select “Session” in the menu and then “New Session”.

 

In Session name you can replace “New session” by a more suitable name, e.g., “ALICE 2”.

In the Server settings,

  • set Host to one of the login nodes, e.g., login2.alice.universiteitleiden.nl,

  • set Login to your ALICE user name,

  • set SSH port to 22 if it is not set by default,

  • enable Use Proxy server for SSH connection,

    • set the proxy server Type to SSH,

    • set the proxy server Host to the ALICE ssh gateway, i.e., ssh-gw.alice.universiteitleiden.nl,

    • set the proxy server Port to 22,

    • enable Same login as on X2Go Server,

    • enable Same password as on X2Go Server.

You can also set the path to your ssh key in Use RSA/DSA key for ssh connection if you do not want to authenticate using your password.

In Session type, select either XFCE or MATE.

Finally, confirm the settings by clicking OK.

 

In Session name you can replace “New session” by a more suitable name, e.g., “SHARK 1”.

In the Server settings,

  • set Host to one of the login nodes, e.g., res-hpc-lo02.researchlumc.nl,

  • set Login to your SHARK user name,

  • set SSH port to 22 if it is not set by default,

  • Enable Use Proxy server for SSH connection if you need to use this session for connecting from outside the LUMC:

    • set the proxy server Type to SSH,

    • set the proxy server Host to the LUMC ssh gateway, i.e., res-ssh-alg01.researchlumc.nl,

    • set the proxy server Port to 22,

    • enable Same login as on X2Go Server,

    • enable Same password as on X2Go Server.

You can also set the path to your ssh key in Use RSA/DSA key for ssh connection if you do not want to authenticate using your password.

In Session type, select either XFCE or ICEWM.

Finally, confirm the settings by clicking OK.

Using X2Go

If you have successfully completed the previous step, the X2Go main window will display a tile with the name of the session, the host (without the proxy server), the desktop environment, the desktop resolution of your X2Go session and sound enabled/disabled.

By clicking on the desktop resolution, you get a drop-down menu from which you select alternative resolutions.

By clicking on the tile, X2Go will initiate the process to connect to ALICE or SHARK. If you have not set your session to use ssh keys, X2Go will ask for ALICE or SHARK user password.

After you successfully authenticated, it usually takes a few seconds for X2Go to start your desktop environment on ALICE or SHARK.

When you are finished using your X2Go session, please log out of your desktop environment and do not just close the window in order to properly terminate your session. Otherwise, your session will be suspended and consume resources. We regularly check suspended X2Go sessions and terminate them if necessary.

Editing your existing X2Go session

The three horizontal lines in the bottom right corner of the session tile, allow you amongst other things to access the session preferences.

Available desktop and how to log out of your X2Go session

The following desktop environment are available:

  • on ALICE: XFCE, MATE

  • on SHARK: XFCE, ICEWM

The screenshots below give an impression of how the different desktop environments look like. The actual appearance of the desktop can vary between SHARK and ALICE and from user to user.

ICEWM

ICEWM is only available on SHARK

The ICEWM desktop for a new session

In order to log out, click on bottom-right icon, select “Logout” and then “Logout”.

Confirm that you want to log out, by clicking “OK” on the appearing overlay window:

MATE

MATE is only available on ALICE

The MATE desktop for a new session

 

In order to log out, click on “System” in the menu bar and then select “Log Out <user-name>”, where <user-name> is your ALICE user name.

Confirm that you want to log out, by clicking on “Log Out” on the appearing overlay window:

If you are seeing graphical issues when using MATE, try to disable the compositing window manager.

To do this:

  • Go to “System -> Preferences -> Windows”

  • in “Window Preferences” (see screenshot), disable “Enable software compositing window manager” under “General > Compositing Manager”

 

XFCE

The XFCE desktop for a new session

In order to log out, click on Application in the top-left menu and select “Log out”.

An overlay window will appear, asking you to confirm by clicking once more on “Log Out”.

 

 

 

Mounting a local folder to the X2Go session

To easily access files from your local machine in your X2Go session, you can share local directories.

This can be configured during the first set-up of the session, or by editing an existing X2Go session.

Do note that accessing the files will happen over the network (they are not actually on ALICE or SHARK) and the share will of course close when you log off from X2Go. So this feature is most useful for quick lookups or for easily copying the files to your home directory.

In the Shared Folders tab of the Session preferences:

  • click on the folder icon next to the add button,

  • navigate to the directory on your local machine that you wish to share and click select folder,

  • then click on the add button,

  • make sure the checkbox for Automount is ticked,

  • using the steps above you can add multiple local folders,

  • finally, confirm the settings by clicking on OK.

When the session has started, you can access the file manager (or the terminal) to find you local folders under: /home/[USERNAME]/media/disk/

The names of the top directories may look a bit strange (e.g. starting with "_cygdrive"), but the file and foldernames within should look correct.

Best Practices

  • Always logout of your desktop environment in order to properly terminate your session. Do not just close the window because this will keep your session suspended consuming resources on the login nodes.

  • While there is most likely always a limited amount of time lag involved when using X2Go, you can try to improve the performance by changing the Compression Method in Sesssion preferences -> Connection.

Known Issues

  • There is a known issue that results in breaking the copy-and-paste functionality from the host to the server or the other way around. In some cases, it helps to enable do not use primary cliboard in Options -> Settings -> X.Org Server settings. Otherwise, it might be necessary to restart X2Go.

  • Disable the setting “Client side printing support" in the Media tab of the settings. This setting has caused issues with establishing a connection and performance.