Conventions and Tools » History » Version 36

Version 35 (Teresa Lackey, 09/09/2016 12:36 PM) → Version 36/48 (Teresa Lackey, 09/09/2016 12:36 PM)

h1. Conventions and Tools

h2. 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":;filename=UsingDesktopVNCIcons.pdf for a User's Guide.

h3. VNC Servers

To set up VNC servers for the control room, see the [[VNCSetup| VNC Setup How-To]].

h3. 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
<pre> vncviewer -Fullscreen -Shared -passwd ~/.vnc/passwd :<NN> </pre>
<pre> -Fullscreen # starts in full screen mode
-Shared # keeps other users from getting disconnected from the server when you connect
NN # two-digit port number (relative to 5900) </pre>

h2. Conventions

h3. 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.

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

| *Abbreviation* | *Host* | *Used in standard ROC?* |
| NDOS | novadaq-ctrl-master | No |
| NDSBTest | novadaq-ctrl-master | No |
| FarDet | novadaq-far-master-02 | Yes |
| NearDet | novadaq-near-master | Yes |
| NearGateway | novadaq-near-gateway-01 | Yes |

(See [[novadaq_apdtest:]] for more information on NDSBTest)

The next table gives machine, account, and port information for each of the six stations used at a Remote Operation Center (ROC):

| *Station* |*Functions* | *Host* | *Account* | *Gateway* | *Remote Port* | *Gateway Port* | *Local Port* |
| 1 | FD Run Control
Message Logger | novadaq-far-master-02 | novacr01 | novadaq-far-gateway-01 | 5951 | 5903 | 5981 |
| 2 | FD Event Display
Online Monitoring
APD Cooling GUI | novadaq-far-master-02 | novacr02 | novadaq-far-gateway-01 | 5952 | 5900 | 5982 |
| 3 | Synoptics | nova-cr-03 | novacr03 | novadaq-near-gateway-01 | 5953 | 5902 | 5993 |
| 4 | Camera pages
beam pages | webpage | | | | |
| |
| 5 | ND Run Control
Message Logger| novadaq-near-master | novacr01 | novadaq-near-gateway-01 | 5951 | 5900 | 5991 |
| 6 | ND Event Display
Online Monitoring
APD Cooling GUI | novadaq-near-master | novacr02 | novadaq-near-gateway-01 | 5952 | 5901 | 5992 |

The *gateway* and *gateway port* are what you need to know to set up your own SSH tunnels so that you can view the sessions from your local machine. The *local port* is a recommendation for what port to use on your local machine.

The servers for each of these is set up to occupy a 1x2 monitor grid, with total pixel count 2650x2880.

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.

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.

h3. 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
<pre>ssh -L <local_port>:localhost:<remote_port> -N -f -l <remote account> <remote host> </pre>
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 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

h2. Example

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"
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.