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--- uva_msc_radioastronomy_2013_vnc [2013/04/03 20:56] – leeuwen
+++ uva_msc_radioastronomy_2013_vnc [2013/04/16 15:54] (current) – [2. Start the VNC session at the LOFAR cluster] leeuwen
@@ Line 6: / Line 6: @@
-==== How Do I Get the Necessary Software? ====
+==== 1. How Do I Get the Necessary Software? ====
-=== Windows ===
 VNC comes with most Linux distributions and is easily set up. Mac and Windows users should download and install a VNC Viewer.
+=== Linux ===
+Install vncviewer software if you don't have any yet.
+Then, log in to the LOFAR portal
+ ssh USER@portal.lofar.eu
+Where USER is the lodsXX account you received
+=== Windows ===
 VNC for Windows is freely available from TightVNC (www.tightvnc.com) or from RealVNC (www.realvnc.com).
@@ Line 23: / Line 35: @@
 In the configuration window, specify the host name, portal.lofar.eu  and click on Open to obtain a terminal window to the host. (After specifying the host name, one can choose Save to save the session for future use. If the host name already appears among the Saved Sessions, double click on the host name to open a terminal window to that host.)
@@ Line 43: / Line 54: @@
-==== Start the VNC session ====
+==== 2. Start the VNC session at the LOFAR cluster ====
-At the prompt on portal type:
+As this session will continue to "live" after you log out, you probably only have to do this once.
+First set up the "window manager" for your virtual machine:
+edit (with pico, vi, etc) the file
+''~/.vnc/xstartup''
+to be:
+  #!/bin/sh
+  icewm-session &
+Then, at the prompt on portal type:
 vncserver
 You can also run vncserver with color depth or window size options. For example:
 vncserver [ -geometry 2048x1024 ] [ -depth 8 ] [-pixelformat BGR233]
+The first time you run vncserver it will ask you to set up a vnc password. Just use the one that came with your account.
+Once you have typed vncserver, the system will reply (e.g.) "New 'X' desktop is portal:2". In this example the VNC session number is 2. Remember this number since you will need it later. In the instructions below, the VNC session number is designated as n. If n is smaller than 10, use 0n (e.g., 02).
+Leave this connection to the server open, as it will be used later to kill processes associated with the VNC session.
-==== How Do I Start a VNC Viewer on My Local Machine? ====
+==== 3. How Do I Start a VNC Viewer on My Local Machine? ====
 You will need to establish an SSH tunnel and start a VNC viewer in order to view the session on your local machine (work/home). The process is different for each computer platform:
@@ Line 63: / Line 89: @@
 === Windows ===
+To establish an SSH tunnel:
-To establish an SSH tunnel:
 Start another instance of PuTTY and bring up another PuTTY Configuration window.
@@ Line 74: / Line 99: @@
 Connection > Data - Enter your account login name as the Auto-login username.
-Connection > SSH - Select Enable compression.
+Connection > SSH > Tunnels - Remove any previously used ports with the Remove button. For Source port enter 59n, where n is the VNC session number reported in the first PuTTY window (the VNC server). For Destination, enter localhost:59n . For example: localhost:5902 or localhost:5972 . Then choose Add, then Open.
-Connection > SSH > Tunnels - Remove any previously used ports with the Remove button. For Source port enter 590n, where n is the VNC session number reported in the first PuTTY window (the VNC server). For Destination, enter localhost:590n Then choose Add, then Open.
+A terminal screen will open. If you are not using an SSH agent, you will be prompted for your lodsXX account password.
-A terminal screen will open. If you are not using an SSH agent, you will be prompted for your NRAO Linux account password.
 You need type nothing else in this window except exit at the end of the VNC session. The existence of this window serves only to provide the tunnel from your Windows machine to the Green Bank system.
@@ Line 87: / Line 110: @@
 A popup window will appear, VNC Viewer: Connection Details.
 Click on Options. Search for and select the option for sharing the connection and then click OK.
-For Server enter localhost:n, where n is the VNC session number, as before.
+For Server enter localhost:n, where n is the VNC session number, as before (but here, without preceding zero).
 Next a VNC Viewer: Authentication window will pop up. Enter your vncserver password
@@ Line 95: / Line 120: @@
 To establish an SSH tunnel AND start a VNC viewer, open a terminal on your local computer and type:
-vncviewer -Shared -via YOURLOGIN@portal.lofar.eu localhost:n
+vncviewer -shared -via YOURLOGIN@portal.lofar.eu localhost:n
 Replace n with the desktop number from the previous step and YOURLOGIN with the name of your account.
-The -Shared option allows support staff to "snoop" on your session when assisting you.
+The -shared option allows support staff to "snoop" on your session when assisting you.
-If you are not using an SSH agent, you will be prompted for your NRAO Linux account password.
+If you are not using an SSH agent, you will be prompted for your lodsXX account password.
-You will next be prompted for your VNC password, which should be different from your NRAO Linux account password and sharable with support staff. You will be asked for this password regardless of whether or not you have an SSH agent running.
+You will next be prompted for your VNC password. Use the same password. You will be asked for this password regardless of whether or not you have an SSH agent running.
 Note: If your Linux version does not support the -via option you might want to install Tight VNC (www.tightvnc.com) or use the following equivalent to -via:
@@ Line 111: / Line 135: @@
 Open a terminal on your local computer and type:
+ssh -N -C -L 590n:localhost:590n YOURLOGIN@portal.lofar.eu
-ssh -N -C -L 590n:localhost:590n YOURLOGIN@portal.lofar.eu &
 Open a terminal on your local computer and type:
+vncviewer localhost:n
-vncviewer -Shared localhost:n
 The VNC Viewer window to the lofar portal will now appear.
@@ Line 124: / Line 146: @@
 To establish an SSH tunnel, open a terminal on your Mac and type:
 ssh -N -C -L 590n:localhost:590n YOURLOGIN@portal.lofar.eu
@@ Line 140: / Line 161: @@
 The VNC Viewer window to lofar will now appear.
+===== Troubleshooting ====
+If you get the error "no free display number on machine", use the lofar backup portal. In the above instructions, substitute portal.lofar.eu everywhere with 195.169.3.218 .