Actions

Login to ALICE using X2Go

From ALICE Documentation

About X2Go on ALICE

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

On Alice, you can currently choose between two different desktop environments: XFCE and MATE. X2Go can be used on both login nodes.

Getting X2Go

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

Setting up the connection to ALICE

In order to create an X2Go session for ALICE, open the X2Go client and select Session -> New session in the menu bar. This will open an overlay window in which you specify the settings for ALICE.

In Session name you can give this session a name. Here, we will call it ALICE Login 2 because we will set this session up to connect to login node 2. Of course, you can also connect to login node 1.

In Server settings,

  • set Host to login2.alice.universiteitleiden.nl,
  • set Login to your ALICE user name,
  • set SSH port to 22,
  • enable Use Proxy server for SSH connection,
    • set the proxy server Type to SSH,
    • set the proxy server Host to the ALICE ssh gateway 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.

Connecting to ALICE with 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. If you have not set your session to use ssh keys, X2Go will ask for ALICE user password.

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

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.

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) 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:

  • 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.