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: http://www.atnf.csiro.au/computing/software/askapsoft/sdp/docs/current/platform/casa.html
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While the ASKAP Central Processor was not specifically designed to run CASA, there are a number of approaches to using CASA. It can be run on the compute nodes, however there is no X-Windows system there, so GUI tools such as casaviewer, casabrowser & casaplotms will not work. We do have a number of (temporarily) “spare” nodes which we can temporarily dedicate to CASA usage. These are Dell servers with 64GB RAM. However these nodes are part of the ingest pipeline infrastructure and will be dedicated to that purpose as more antennas come online.
The two nodes that have been earmarked for temporary CASA usage are galaxy-vis1 and galaxy-vis2. Two approaches to running CASA are described below: 1) using VNC and 2) using X11-Forwarding.
Warning
Neither casapy nor any of the CASA GUI tools (casaviewer, casabrowser, casaplotms) should be executed on the login nodes (eslogin-rt000 or eslogin-rt001). Using these tools often results in memory exhaustion and will hang the login nodes, preventing all users from accessing the system.
A remote desktop environment can be accessed via VNC. Either of the two visulisation servers can be used to host a VNC server. First you must login to one of the visulisation servers and start the VNC server:
ssh galaxy-vis1.pawsey.ivec.org
vncserver -geometry 1024x768 -depth 24
Note, you may choose any geometry you want, 1024x768 is just an example. You may wish to run the VNC session in full-screen mode, in which case the geometry should match your monitor. You will then be prompted to enter a password. Be sure to choose a secure password, as anyone within the iVEC network can potentially connect to your VNC server. You will also be prompted to enter a view only password, you can answer no to this. You will then see output similar to the following:
New 'X' desktop is esDM015:1
Starting applications specified in /home/hum092/.vnc/xstartup
Log file is /home/hum092/.vnc/esDM015:1.log
Shortly you will be configuring your VNC client and you will need the number after the full-colon in the first line, in this case “1”. Now the VNC server is started and is waiting for your VNC client to connect. You are free to use the VNC client of your choice, however as you will be connecting via an SSH tunnel (the VNC port is blocked at the iVEC firewall) you will want a client with SSH tunnelling support. On Mac OSX the VNC client “Chicken” works well.
Once you connect with your VNC client you can start a terminal and launch CASA like with the following commands:
module load casa
casa
While you may wish to leave your session running for long periods of time, you should be sure to kill it when you are no longer using it. Each VNC sessions requires memory, and with many users it is possible to exhaust available memory. The VNC server can be killed with the following command:
vncserver -kill :1
Note the “1” should be replaced with the display number you recieved when executing the vncserver command.
The default desktop manager, TWM, may be unfamiliar. You can use GNOME instead, which provides a more familiar windowing environment. To use GNOME:
Kill the VNC server you have started (ignore this step if you have not got a server currently running)
Edit the VNC xstartup file (~/.vnc/xstartup) to only contain the following:
#!/bin/sh
/usr/bin/gnome-session
Start the VNC server using the instructions described above.
The GUI tools can be used and will be displayed on your desktop via X11-Forwarding. This approach is better suited to local machines, and you will notice it is not particularly fast.
The following commands will launch CASA:
ssh -Y galaxy-vis1.pawsey.ivec.org
module load casa
casa
Note you can choose from galaxy-vis1 or galaxy-vis2. These nodes share the home directory with the Cray supercomputer itself and also mount the /scratch2 filesystem.
Note
CASA has not been well tested on the Cray platform, and indeed CASA is not designed to be run in a HPC environment.
An interactive CASA session can be run on a compute node using the salloc command to allocate a node for an interactive session:
salloc --nodes=1 --mem=64G
Upon invoking this command one of two things will happen:
From here you can load the module for CASA and execute CASAPY:
module load casa
aprun -b casa --nologger --log2term --nogui