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Keith Matera, 05/10/2016 01:12 PM


Conventions and Tools

Overview

The user interface environment to the DAQ system is hosted in VNC servers running on DAQ cluster computers at various sites. Users interact with these via VNC viewers hosted on control room desktops, and for experts, on their own desktop or laptop.

The NovaControlRoom package contains icons and scripts to automatically set up the needed ssh tunnels, and launch the VNC viewers. See docdb-8406 for a User's Guide.

VNC Servers

To set up VNC servers for the control room, see the VNC Setup How-To.

VNC Viewers

The command to start a viewer is including in the script launched by the desktop icons described in the User's Manual mentioned above, but the underlying command is of the form

 vncviewer -Fullscreen -Shared -passwd ~/.vnc/passwd :<NN> 

where
 -Fullscreen # starts in full screen mode
 -Shared # keeps other users from getting disconnected from the server when you connet
 NN # two-digit port number (relative to 5900) 

Conventions

VNC Servers

In the current model (as of 2016-05-10), we employ 2 VNC servers for each detector. In order to allow for different desktop environments on a single host machine, each VNC server on is run under a different account, using a dedicated port. We tend to use certain servers for particular functions, but this is subject to change.

Station Functions Account Port
1 FD Run Control
Message Logger
novacr01 5951
2 FD Event Display
Online Monitoring
APD Cooling GUI
novacr02 5952
3 Synoptics novacr03 5953
4 Camera pages
beam pages
N/A N/A
5 ND Run Control
Message Logger
novacr01 5951
6 ND Event Display
Online Monitoring
APD Cooling GUI
novacr02 5952

The servers for each of these is set up to occupy a 2x2 monitor grid, with total pixel count 3840x2160.

Two VNC servers run on the nova-daq-04 Control Room desktop in the Fermilab 1st floor control room, hosting webcam displays. From off-site, webcam and beam pages can be found on the What to do on Shift links site.

Note that VNC has a port base of 5900. However, in addition to the VNC connection itself, it also uses a port for the X11 connection 100 higher than the VNC port. Since general X11 connections use ports starting at 6010, and assuming less than 40 open connections is a safe bet, a good assumption for VNC port ranges that avoid conflicts with X11 would be 5900-5909 and 5950-5999.

The table below gives the VNC server host name used for each system:

Detector Host Status
NDOS novadaq-ctrl-master Defunct
NDSBTest novadaq-ctrl-master Defunct
FarDet novadaq-far-master-02 Operational
NearDet novadaq-near-master Operational
NearGateway novadaq-near-gateway-01 Operational

(See novadaq_apdtest for more information on NDSBTest)

ssh Tunnels

ssh tunnels are required to access the port for a VNC server on a remote host (e.g., for station 1 on NDOS) from a localhost (e.g., your laptop, or a control room desktop). Once launched, the tunnel can remain active indefinitely. The ssh command has the form

ssh -L <local_port>:localhost:<remote_port> -N -f -l <remote account> <remote host> 

The ssh tunnel is authenticated using a kerberos ticket on the localhost, usually for a special use (i.e., non-personal) principle. That principle must be in the k5login file for the remote account, and the remote host must be directly reachable from the localhost (i.e., the localhost must be in the fnal.gov domain.)

Since a single desktop will often have connections to the "same" display on multiple detectors, we need to have localhost port assignments vary by detector. The scheme in use by the NovaControlRoom package is

Station Detector Remote Port Local Port Status
1 NDOS 5951 5961 Defunct
2 NDOS 5952 5962 Defunct
3 NDOS 5953 5963 Defunct
1 NDSBTest 5955 5971 Defunct
2 NDSBTest 5956 5972 Defunct
3 NDSBTest 5957 5973 Defunct
1 FarDet 5951 5981 Operational
2 FarDet 5952 5982 Operational
3 FarDet 5953 5983 Operational
1 NearDet 5951 5991 Operational
2 NearDet 5952 5992 Operational
3 NearDet 5953 5993 Operational
1 NearGateway 5902 ???? Operational

Example

EXPERTS ONLY
On Windows, using RealVNC Viewer (renamed to vncviewer.exe), MIT Kerberos for Windows, and plink; the following batch file (FarDet1.bat) connects to the first screen of the Far Detector:
Start plink -ssh -L 5981:localhost:5981 <Principal>@<Gateway> "ssh -L 5981:localhost:5951 -N "
pause
start vncviewer -Shared -passwd passwd localhost:81

passwd is a file with the MD5'd VNC viewer password, and <Gateway> is a machine connected to the Fermilab network accessible from the outside. Using the tables above, it is possible to connect to any detector/station combination.