3D Desktop Support
This article discusses the current status of GNOME 3 support for the Exceed product line. GNOME 3.8+ is an OpenGL-based 3D window manager that comes as the default window manager in RHEL7 and CentOS7.
1. OpenText Exceed onDemand™ cannot launch GNOME 3 desktop.
2. Connecting to GNOME 3 desktop with OpenText Exceed™ or OpenText Exceed TurboX may result in the following behaviors:
- The connection may fail with an error
- The session may be slow
- The user may see black icons and windows (or other graphical issues)
- Network traffic between the X server and X client (GNOME 3 host) will be very high.
GNOME 3 was designed to work with direct OpenGL rendering, and may either fail or perform poorly over a remote connection. Failure may occur due to the desktop using OpenGL capabilities that are not available remotely. Slow performance and high network usage are a result of rendering methods that are not designed for remote connections (sending uncompressed X11 bitmaps over the network every frame). Graphical issues, such as black icons and windows, can be caused by unsupported (non-Mesa) graphics drivers.
Exceed TurboX (ETX) includes a server-side proxy that compresses the X11 traffic before sending it across the network. The proxy can be installed on the same server as the 3D desktop to avoid flooding the network connection between the proxy and desktop host. In addition to compressing the display, the ETX proxy can also skip frames to reduce the bandwidth required for the remote display.
The reason that GNOME 3.8+ does not work with OpenText Exceed onDemand (EoD) is unrelated to performance. This issue is caused by GNOME's use of unsupported X protocol extensions (XFIXES 5.0 and XInputExtension 2.2) which are not available in EoD's older X.Org server codebase. To connect to GNOME 3 desktops, EoD customers should upgrade to ETX, which uses the latest X.Org codebase.
There are several recommended solutions / workarounds for connecting to hosts running GNOME 3:
Use a 2D desktop environment and display manager. Desktop environments like MATE and Cinnamon are GNOME-like alternatives that offer the same familiar interface but with excellent remote performance. Display managers like gdm2, mdm and LightDM also work remotely and do not require the Exceed 3D add-on. If you require a full Linux desktop, this is the best solution.
Note: Once the 2D desktop environment is installed, you will need to select it from the XDMCP login screen.
Example: Installing MATE and LightDM on CentOS 7
sudo yum install epel-release
sudo yum groupinstall "MATE Desktop"
sudo yum install lightdm
systemctl disable gdm.service
systemctl enable lightdm.service
#Add the following to /etc/lightdm/lightdm.conf to enable XDMCP
Run applications directly rather than XDMCP (desktop) sessions. Both Exceed and Exceed onDemand allow you to define an Xstart (.xs) file to launch one or more applications on the same host. Xstart files will significantly improve the performance of your remote sessions, even when running on machines that have a 3D desktop environment installed. You can also run remote applications on a GNOME 3.8 machine using Xstart files.
Upgrade Exceed or Exceed onDemand to Exceed TurboX (ETX). ETX provides fast remote access, central administration and deployment options, enterprise scalability, and central, web-based access for both large enterprises and small organizations. ETX is based on the latest X.org server, and includes the necessary extensions to support a remote GNOME 3.8 session. Some limitations and additional configuration may be required for 3D desktop support - please contact your local sales or support office for assistance.