In general x2go is easier to use and sufficient for most scenarios. Xpra has more features and generally better performance. Both clients connect through ssh and run faster than ssh -Y. Support for these is beta, x2go is more familiar to the staff. Most linux systems do not have these tools installed, so you may need to request them.
It relies on a gui and can connect to new sessions over ssh.
x2go can be downloaded from this page.
You will need to open System Preferences - Security - General - Temporarily 'Allow from anywhere' open the application, make sure you can reopen it. Then change your security setting back to 'App Store and Identified Developers'
Off the sbgrid network it will be easiest if you use the vpn.
x2go requires XQuartz - see faq-using-sbgrid-programs.
From the x2go application - Create a new session Make sure you fill out host - the host that you want to connect to. login - your username port - 22 Session type - Mate
You can adjust the resolution after the session has started.
xpra has been described as 'tmux for X11' and we are evaluating its usefullness.
For Mac OSX newer than 10.9 the installer is on their downloads page https://www.xpra.org/trac/wiki/Download
For our usage please us the 'pkg' installer located here - https://xpra.org/dists/osx/x86_64/Xpra.pkg
The other version is built around a gui that we are not covering for now.
On your local Mac OSX system open a terminal window and run
xpra start ssh/oconnor@sch-boltzmann/42 --start-child=xterm
With this one command you should have a remote xterm window come up. From there you can launch whatever application you need to run on the other system, including applications that need GLX extensions such as coot.
To disconnect, just ^c from the original terminal window(not the xterm that you connected to), or if you connect from another system it will automatically detach.
So to reattach to attach -
xpra attach ssh/oconnor@sch-boltzmann/42
Note the number 42. You need to pick a number that someone else on the system is not using. Do not use a low number that could be inuse by the system like 0 - 5, instead pick a higher number up to 999.
Note, if you simply close all the windows, including xterm, the remote server is still running
Found the following xpra sessions:
LIVE session at :666
xpra stop :666
xpra at :666 has exited.
Or one might have run
xpra start ssh/oconnor@sch-boltzmann/42 --start-child=xterm --window-close=shutdown
,but if you accidentally close the window everything will close.
In summary, If I am off site and want to create a new session on one of our systems -
'ssh -L 4444:ja-gpu1:22 -N firstname.lastname@example.org'
open a new terminal and then -
xpra start ssh/oconnor@localhost:4444/617 --start-child=xterm --window-close=shutdown
Ideally you would have already set up password-less ssh.
Make sure you can ssh to the host without error. You should not need to type 'yes' for ssh keys, etc.
Press enter one time - is it waiting for password input?
connect to the remote host and type -
If there is an active session you can connect to it via `xpra attach ssh/user@host/42' from your client.
There could be an active session with no windows open. Stop the session and start again. 'xpra stop :42`
Lastly try to launch a session from the host in a tmux or screen session on the remote server -
You should see a line that that contains xpra is ready.
Detach with CTRL-b - d keys and then you can attach from your own system like so
xpra attach ssh/oconnor@sch-boltzmann/617`
The launching from within a tmux or screen session might be easier to experiment with other flags like "start-desktop" `xpra start-desktop –start=mate-session :618 –daemon=no'
See Also `man xpra'
There are a lot of features, but for our usage keep it simple.