Getting Started - Connecting

Overview

There are multiple ways to connect to Jefferson Lab, but the most stable over long distances is the VDI - Virtual Desktop Environment. This is followed by vncviewer/vncserver. The last resort connection type is X11 port forwarding over an ssh connection. Like any connection over the internet the main issues are bandwidth and latency.
One can ping the jlab speedtest page to check your connection:
speedtest.jlab.org

X11 port forwarding is the slowest option because it pixel-by-pixel updates the display even if no new information has been updated for the pixels. This is sped up considerably in vncservers which send only the information about pixels that have changed and keystrokes from remote computer to the host (computer) vncserver session. VMware is the fastest because it streams even less information to the remote computer because a lot of the UI is hosted on the remote machine. This minimizes the amount of information transmitted over high-latency networks with low bandwidth.

Another option is to use jupyter notebooks and python code. Jupyter notebooks are edited in the browser and hosted via a connection to a farm node. This is quite stable but is limited in usability as the terminal kernel is limited and information is not saved on the server intermittently. It is only saved when the user actually saves it. Clearing the chrome or firefox cache could lose edits.

VDI - Virtual Desktop Environment

IMPORTANT: When logging into VDI, you must select 'CNIADS' from the domain drop-down menu.*

The IT Division provides a virtual desktop environment called "JLab VDI". This environment can be accessed on-site and off-site using the instructions below. We have Windows and Linux VDI environments. Here are the instructions for accessing these environments:

1. Open Firefox or IE and go to https://vdi.jlab.org
2. Install the client software
   • Download the software by clicking “Install VMware Horizon Client”
3. Download the VMware Horizon Client appropriate for your system
   • A “VMware Horizon Client” will be created on your desktop
   • Double click icon, select "+New Server" and type “vdi.jlab.org”
   • A new icon for vdi.jlab.org will be created on your desktop
4. You will need to request the IT Help Desk for a Linux environment. Otherwise your sole option would be a Windows 10 environment which is probably useless.
5. Double-click new icon and login with your JLab CUE username and password; keeping CNIADS* as the domain

NOTE: The VDI environment requires the follow ports to be open - TCP\UDP- 4172, TCP- 22443, TCP-32111, TCP-8443, TCP-443, and TCP-9247. Port 4172 is the most important.

If you have any questions or concerns regarding VDI, please contact the IT Division Help Desk (helpdesk@jlab.org or x7155).

VNCViewer

Users can access the JLab Common Users Environment (CUE) by tunneling through the login1 or login2 server at JLab.
ssh -t -L6437:localhost:5912 cmorean@login2.jlab.org ssh -t -L5912:localhost:5912 <destination_computer>

• The red are already in use and you should CHANGE to a different port for your use. (Refer to the list below to see which ports are already in use).
• It is common to connect to chislobog (XEM only), ifarm, or jlabl1 - jlabl3.
• In order to use a vncserver, you will need to use a computer other than an ifarm computer.
  • Highly recommended over x11 port forwarding because of connection speed requirements
  • You can check your connection speed to JLab is not the problem by using JLab's SpeedTest.

Issues with WSL

The initial WSL (windows subsystem for linux) LANG is not set properly for JLab. You will need to edit /etc/default/locale to
LANG=en_US.UTF8
If this is not set properly, you will be unable to open a terminal window in a vnc session. You will also get a few perl issues upon logging into JLab above the title screen.

Used Numbers

Once you use a number note it on this list. Update this list or contact someone who can.

Chislobog Ports In Use

Port Number	User
06	Ramon
07	Nadia
12	Casey
13	Abhyuday
16	Ryan

VNC Server Setup

1. Insure VNC Viewer is installed on your computer.
2. Start the VNC viewer process on <destination_computer>. vncserver -geometry 1920x1080 :12
3. Open the VNC application on your computer.
   • Click file --> New connection... --> A new window should pop up
   • For IP address or host name use localhost:6437
   • Name this VNC connection anything you will remember and click Okay
4. Other Useful VNC Commands
   • To kill a VNC server on <destination_computer> vncserver -kill :12
   • To set a new VNC password vncpasswd
   • To edit the VNC window render resolution, change the numbers in blue for the command vncserver -geometry 1920x1080 :12

• The 12 should be the same number as you chose in the previous section.

From a JLab Computer

1. From a terminal: ssh ashard@scilogin.jlab.org
2. Enter your password through the MobilePASS app(contact helpdesk@jlab.org if you don't have this setup)
3. ssh ifarm
4. Enter your JLab account password

Using PuTTY to SSH

• Currently not recommended, but possible with the right configuration.

Common Connection Issues

• Tunneling Problems
  • Conflicting or incorrect SSH keys in known_hosts
• VNC Server Problems
  • If you tunnel and only specifying login.jlab.org, the machine will choose either one or the other, which sometimes breaks vncservers for UNKNOWN REASONS.
  • VNC Servers should be started on the port highlighted in red using the command <vncserver -geometry 1920x1080 :<port_number>
  • VNC Servers started on different destination_computer are not accessible if you login later to some other destination_computer.
  • The computer was restarted, so the vncserver was shut down.
• JLab /group/ /work/ /volatile/ Directories Missing (Hanging)
  • Sometimes work on connection gateways will break Lustre file system connections that are not tier-1
  • Improper JLab farm node use can cause the Lustre file system to hang. Report an incident report using the Incident Report Utility