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Note: FastX means FastX2. The older FastX client prior to v2.x is obsolete and doesn't work anymore. If you are using Netinstall/DSM: install FastX 2.0, don't use the client in the Xwin32 package!


Starnet FastX2 provides a fast and easy way to access linux compute resources with full X-support from various platforms (OsX, Windows, Linux). 

Information

FastX2 Server Availability

In contrast to Xwin32, FastX2 requires a FastX2-server installation on the remote host. FastX2-Server is currently installed on a few central login nodes:

  • PAL, PAUL open for everyone with a DESY account
  • max-display open for users of the maxwell-cluster
  • max-nova open for members of the NOVA project
  • max-fsc, max-fsg open for FS users
  • max-cfel, max-cfelg open for CFEL wgs users
  • nafhh-x1, nafhh-x2 for NAF users

Usually PAL (RedHat) or PAUL (Ubuntu) would be your prime choice. For these (as well as max-fsc/g and max-cfel/g) you will need to connect through bastion (or desy-ps-ext.desy.de for external Photon Science users) and setup an ssh-tunnel. For documentation on the ssh-tunnel please check Remote Access / SSH. The table below summarizes sum of the features of the various login nodes.


Node/ClusterOSHomeWMWeb-Service

Clustered Gateway

GPU accelerationServerClientRestrictions
paulUbuntu 18.04AFSXFCEyesnonotbdtbdOnly accessible via bastion
palScientific Linux 6.xAFSXFCEnonono

Only accessible via bastion
pal-el7Centos 7.xAFSXFCEyesnono

Only accessible via bastion.
max-displayCentos 7.xgpfsXFCEyesyesyes

Only accessible with maxwell-resources. Please read Remote Login page (confluence login required)
max-novaCentos 7.xgpfsXFCEyesyesyes

Only accessible for nova users. Please read Remote Login and FastX NOVA Instructions (confluence login required)
max-fsc/gCentos 7.xgpfsXFCEnonono

Only accessible for PS users
max-cfel/gCentos 7.xgpfsXFCEnonono

Only accessible for cfel users (restricted to some groups)
nafhh-x1Ubuntu 18.04AFSXFCEyesnono

no restrictions
nafhh-x2Centos 7.xAFSXFCEyesnono

no restrictions

Only max-nova and max-display are currently featuring GPU acceleration and node-clustering. For all other nodes you have to remember the node your session was running on to be able to re-connect to that session! To give an example: opening a FastX2 session on max-fsc connects e.g. to max-p3a007. The suspended session will remain on max-p3a007. Some time later the DNS-loadbalancer will resolve max-fsc as max-p3a001. A FastX2-connection to max-fsc will then not be able to discover the suspended session. You need to point the FastX2-client or browser to max-p3a007 to be able to resume the session.

FastX2 client or Web-Browser?

FastX2 offers two different ways to access a Linux Desktop remotely, either by using the FastX2 client or by accessing the Web-Service using a web-browser. Detailed explanations how-to are shown below. What's the better choice depends a bit on the kind of usage pattern and choice of host. Web-Services are not available on all nodes (see table above). So if you connect to pal, max-fsc/g or max-cfel/g you don't have a choice and have to use the FastX2 client. If you intend to use the desktop sharing feature, you have to use the Web-Service, the client doesn't currently support sharing (well). The FastX2 client is somewhat more convenient to use, but there is occasionally a problem with version mismatches of client and server: if you pick the newest client from the Starnet website, there is a chance that the server installations do not yet support the most recent client, and the client will fail to establish a connection. The download linked under "Client" in the table above should however work for all server installations.

Using FastX2 to connect to PAUL

We show here some examples on using FastX2 on paul. It should behave pretty much the same way on other nodes as well. Please note, that look and feel of the client rapidly changes, so the screenshots might look slightly different for your combination of client and server. 

You can connect to a desktop-session directly from your favorite browser. It should work with all commonly used browsers. Point your browser to https://paul.desy.de:3443/. Some browser will show a certificate problem (even though the server delivers a valid certificate). In that case set the security exception.


Using FastX2 in the browser


Specify DESY credentials, and you should get a connection:

Select "add a new session [+]"

Click on the XFCE(VirtualGL) button and hit "Start".

If your popup blocker is preventing the automatic start of your session select your session from the list.

your session will start in a new tab. To terminate a session click

on the Applications button on the top left and "Log out"

Move the pointer to the top of the FastX2-screen. A small menu/panel appears providing access to

some configuration and features. With the pin you can keep the mini-panel open. The resize icon

(2nd button) is particularly useful to synch the size of the xfce-session with your browser window.

The sharing button allows you to share a session with other users and even hand over controls.

See below.


Desktop Sharing

The FastX2 web application allows to share a desktop session with arbitrary users, and even hand over keyboard controls to third parties. To do so, clicj on the "sharing-icon" in the top panel, and send the link. Please note, FastX2 is not intended for remote assistance! If you need remote assistance please get in touch with UCO and have a look at http://it.desy.de/services/remote_assistance/bomgar/index_eng.html.

Desktop Sharing

Enable Sharing. Optionally also enable Keyboard control. Send the link to your colleague.

The colleague with the link will see a "login-window" like this, allowing to identify himself.

After connecting to the session, the desktop is  visible in the remote browser with two viewers,

as indicated by the sharing-icon. The shared session can no be accessed by the FastX2 client. It 

will only work within browser sessions.



Using the FastX2 client

The FastX2 client is more convenient to use, has usually better performance and works on all nodes, even those without the web-service available. So unless you intend to use the desktop-sharing feature, this should usually be your best choice. To fully benefit from the clustering feature on max-display and max-nova, you should use a web-based connection method in the FastX2 client, for all others use the pure ssh-connection, see below. 

If you don't have Netinstall on your windows machine, and no pre-installation on your Linux or Mac client, you can pull the client installer from the link in the table above or simply connect to one of the web-services for example on paul.desy.de:



Using the FastX2 client

To get the desktop client simply follow the link for example on paul or the display nodes.

Download the client of your choice. In the following the non-admin install for windows has been used.

Execute the downloaded installer. For the non-admin install make sure to install into

a separate folder. The installer will otherwise pollute for example your desktop-folder.

Start FastX2 and add a session with the '+' icon. If offers to choose between an "ssh" and a "web" connection. For clustered gateways  on max-display or max-nova you might want to use "web" which offers some features like load balancing. It might cause some problems in certain environments. If in doubt or on nodes without the clustered gateway use ssh.

Create a session (or bookmark). You don't have to specify a user. It will use your local username as a default. Don't alter the "Sci". Save the entry and it will start the session.


In the session window start a new session (or connect to existing sessions if you have any).

Start an xfce session. Leave the window mode as "Single". The window size can be changed any time later. Resist the temptation to use unity. XFCE is much more lightweight, hence less resource consuming, and doesn't rely so much on hardware acceleration.


Changing the size might occasionally require to toggle the resize mode (2nd button on the panel). 


XFCE Keyboard Layout

Keyboard layouts are a bit cumbersome. There are different factors influencing proper detection of the keyboard layout like locale or region settings, browser setting. remote server settings. It your keyboard is not functioning as it should, consider to alter the settings in XFCE as described below. If it still doesn't work properly in your browser (e.g. using ALT-GR affecting all subsequent input) please switch to the FastX client. 

Add a keyboard layout by right-click on the desktop and select the Keyboard setup


Add the keyboard model. The language selection pops up

afterwards. German (dead acute) seems a good choice for

most German keyboards.

Add a panel item by right-click on the panel

Select Keyboard layouts which adds the flags for the layouts

configured. Clicking on the flags toggles the keyboard layout.


If you are not familiar with XFCE, have a look at the XFCE documentation.


Home-Directories

As shown in the table above, the various nodes have different home-directories. Usually that shouldn't matter much, since the different login nodes serve rather different purposes. However, be aware that the AFS-homedir requires an AFS-token to access the files in the directory. A session suspended for more than 24 hours might become unresponsive. On the maxwell-cluster all nodes share the same gpfs-hosted home-directory, which does not depend on any expiring tokens. The homedirs on nafhh-x1/2 are (currently) local. Make sure not to deposit any important data on your homedir! Regularly synch your data for example to AFS.



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