X2Go Remote Desktop

X2Go is an open source, remote desktop solution designed to work well over low and high bandwidth connections.

X2Go is supported on all RDHPCS systems to allow:

• A single graphical MATE remote desktop running on one front end (FE) node.

• The ability to disconnect and reconnect to a session, even from another client.

• Secure traffic through a SSH tunnel.

The RDHPCS does not support these X2Go features:

• support for sound

• file Sharing from client to server

• printer Sharing from client to server

• desktop environments other then MATE

• desktop sharing

Note

The systems at Mississippi State University (MSU) use the web-based application Open OnDemand to facilitate remote desktop connection. Please refer to MSU’s Open OnDemand User Guide for more information.

Requirements

To use X2Go on an RDHPCS system, you must have an active SSH Connection with properly configured SSH tunnels.

Acquire and install the X2Go client on your local system.

Note

If you are not allowed to install software on your local computer please see your local desktop support representative.

Configure X2Go

An example of an RDHPCS configuration for X2Go.

Open the X2Go client (you can use the desktop icon or use run the x2goclient command.), and select Session ‣ New session. If you do not have any configured X2Go sessions, the X2Go client will open the new session dialog window automatically.

Set the following conferation items, then click OK.

Session name:

Name the session configuration something that has meaning to you, for example the system name (Gaea, Hera, etc.)

Path:

/

Host:

127.0.0.1 or localhost

Login:

Use your RDHPCS First.Last username. This is case sensitive.

SSH port:

<ssh_port> This must match your unique SSH local forward port number

Session type:

MATE

Hint

You can change the desktop window size in the Input/Output panel of the session preferences dialog.

Launch X2Go Session

X2Go session window with an RDHPCS host configured.

Open an SSH connection that will establish the SSH local forward to the RDHPCS host. Once the SSH connection is established, open the X2Go client and double click the session in the list in the right side bar. When the authentication dialog box appears, ensure your user name is correct and enter your RSA passcode.

Then click OK to initiate the session. Initial connections may take some time to complete. If your login succeeds, a new window will appear showing you a MATE desktop environment. You are now ready to use your remote desktop as you would on a local system.

Important

CAC Login in the x2go client is not supported.

Important

Your initial SSH Terminal session to the System must remain open’’’* for the X2Go session to work for that system.

X2Go Tips

Some users have found that ensuring that only one connection, the first connection that estabilshes the SSH port forwards, when starting an X2Go session allows for the best chance of allowing X2Go to launch the desktop session. After the X2Go session is active, you can open additional SSH sessions as you desire.

You must have no previous X2Go sessions open on any other nodes on a given RDHPCS system. This is because X2Go places session items in your home directory, and X2Go will try and fail to connect to another, existing session on the current front end node. This can lead to an X2Go configuration that is unusable on that system.

On some systems, you can use the /apps/local/bin/x2go-killallsessions.sh application to make sure you do not have any active X2Go sessions on the system.

It is generally a good idea to exit the session cleanly by logging out or suspending a session. Avoid ending a session by simply closing the window.

Note

The Gaea and PPAN systems do not have the x2go-killallsessions.sh application.

Troubleshooting X2Go

Attention

Not all users have had success configuring X2Go sessions, including members of the RDHPCS support team. We are looking for other, more reliable remote desktop application.

Note

Please read thoroughly through the troubleshooting section before submitting a help request.

Getting X2Go to work can, at times, be difficult. The RDHPCS support team is not sure why this is. If you have difficulties getting X2Go to work, please try the following.

Terminate all SSH sessions

Sometimes, exiting all current open SSH sessions, waiting a moment and then opening just the initial connection to establish the local forward port will help.

Ensure your login scripts are causing an issue

Sometimes user settings in their shell login scripts can cause problems with X2Go. For example, .cshrc, .tcshrc, .profile, .bash_profile, .bashrc. This is especially true if messages are printed to the terminal at login. Try moving these scripts out of the way, and then try establishing the X2Go session.

Try a different bastion

Try a different bastion host for the connections. For example, if you tried using the Boulder bastion, try the Princeton bastion.

Wait a few minutes before restoring an X2Go session

Sometimes waiting a few minutes to connect to a suspended X2Go session will allow you to restore the suspended session.

Avoid editing session configurations with active sessions

The X2Go client can hang if you edit a session while you have an active session. Avoid creating new, or editing existing configurations with open sessions.

.config/caja setting error

X2Go needs to write to the path .config/caja. At times, this path may have the wrong owner information. If you get an error similar to:

The path for the directory containing caja settings needs read and write permissions: /home/First.Last/.config/caja

open a help desk request.

Access Denied

If your login fails with “Access Denied”, you will be sent back to the login screen. This can happen for a number of reasons. Please wait for your RSA token number to change and then try again. If this does not work, please close all SSH sessions to the RDHPCS system and try again.

Cannot connect to 127.0.0.1 or localhost

This error generally occurs when your X2Go session is not working off of a port forwarded RDHPCS session. Please close all RDHPCS system sessions for the system you are attempting to connect to and try again.

Bind address already in use

If you get the message bind: Address already in use on your initial login, this typically indicates wilyou have more than one system session open. For example, you have multiple Hera sessions open. Please close all sessions and open one new session with your configured port tunnel.

Remove stale X2Go sessions and files

If you’ve killed all X2Go sessions, but X2Go is still telling you there are sessions open, run the following command /apps/local/bin/x2go-killallsessions.sh. This should find and kill any lingering sessions and session files that may remain.

If, after running the above command, you are still unable to open an X2Go session, please try the following files:

$ rm -rf /tmp/.x2go-$USER
$ rm -rf $HOME/.x2go/C-*

Connection failed errors with .ssh issues

This kind of error can surface if you have something in your startup scripts (.bashrc, .cshrc, etc.) that would alter the way your shell reacts when it is invoked. For example, starting ssh helper programs, such as ssh-agent from your startup scripts would generate output that could confuse the process of connecting properly for X2Go. Therefore, it is best to remove anything from your startup script that would create any output to stderr, or stdout.

To see if your shell is behaving well in this respect is simple. Start a subshell, and see if you get any output. If you do, eliminate anything in your startup script that is responsible for it.

Additional Checks

Below are some additional items to check if the above have not worked.

• Use pdsh to execute ps commands on a set of nodes looking for any active X2Go sessions. The below example shows how to do this on Hera.

  $ pdsh -w "hfe[01-12]" "ps -eo pid,uname:18,comm | grep x2go | grep $USER | grep -v grep"
  pdsh@hfe03: hfe01: ssh exited with exit code 1
  pdsh@hfe03: hfe03: ssh exited with exit code 1
  pdsh@hfe03: hfe10: ssh exited with exit code 1
  hfe08:  93232 First.Last         /usr/lib64/nx/../x2/x2goagent -extension XFIXES -nolisten tcp -nolisten tcp -dpi 120 -D -auth /home/Raghu.Reddy/.Xauthority -geometry 800x600 -name X2GO-Raghu.Reddy-56-1511972370_stDMATE_dp32 :56
  hfe08:  93345 First.Last         /bin/bash /usr/bin/x2goruncommand 56 93232 Raghu.Reddy-56-1511972370_stDMATE_dp32 37673 mate-session nosnd D
  pdsh@hfe03: hfe07: ssh exited with exit code 1
  pdsh@hfe03: hfe06: ssh exited with exit code 1
  pdsh@hfe03: hfe04: ssh exited with exit code 1
  pdsh@hfe03: hfe05: ssh exited with exit code 1
  pdsh@hfe03: hfe09: ssh exited with exit code 1
  pdsh@hfe03: hfe02: ssh exited with exit code 1
  

• Clean up the $HOME/.x2go directory on both the local and remote system. Please note that removing the $HOME/.x2go on your local machine may remove your X2Go configuration.

• You may consider rebooting your local machine to clear any lingering processes.

• You can try disabling X forwarding for the just the initial ssh session. At least one user found that this eliminated the problem, even though the particular session was not used for anything other than setting up the X2Go session.

Warning

There are pages on the internet that talk about the x2gocleansessions command. Please do not launch this program, it will not help.

X2Go Help Desk Requests

If you still need assistance after reading the documentation, please contact the help desk with the following attached to your help ticket:

• The OS you are using

• The RDHPCS system you are using

• The SSH Client you are using (for example, Tectia, PuTTY, OpenSSH, etc.)

• Include a copy of your SSH client configuration

  • If using CAC, take a snapshot of your CAC Tectia Configuration (the Connection Profile ‣ Connection Page and the User Authentication ‣ Keys and Certificates pages.)

  • If using RSA, take a snapshot of your login session configuration or your ~/.ssh/config file.

• Snapshot of your x2go session preferences configuration settings.

• Any error messages you encountered or where you were stuck in the process

• The bastion you are using (Princeton or Boulder)

• Steps you have already attempted

See also

X2Go client

The X2Go client documentation has some help on configuring the client, and useful shortcut keys.

X2Go FAQ

The X2Go FAQ has some additional troubleshooting tips, and includes information on how X2Go works.