Welcome to a Walkthrough of Gadi
In this document we will aim to walk you through the basics of Gadi, from your first log in, to the submitting and monitoring a job, providing you with step-by-step instructions and information that will guide you.
Don't worry if some of these steps seem like they don't apply to you or your project. If that is the case, simply move on to the next part of the walkthrough. If you find later that you are running into an error, you can come back and go over these steps again and see if something was missed.
To access Gadi, you will need to complete the crucial step of creating an NCI account and becoming affiliated with a project. Our Getting Started at NCI guide can walk you through this process if you haven't already begun.
The next step is to assess what operating system you are using, as that will change how you log into Gadi. Mac and Linux users will be able to use the built-in terminal to access Gadi, however windows users will need to download a 3rd party application, MobaXterm.
Mac users
Mac users can open terminal by clicking the 'launchpad' icon in the dock, type 'terminal' into the search bar, then click on terminal to open it.
Alternatively, you can press 'Command + Space bar', then type 'terminal' and click the icon when it appears.
Linux users
Linux users can go to the 'Applications menu', then locate the terminal icon and click it to open.
Alternatively, you can press 'Ctrl+Alt+T' to use the keyboard shortcut.
Windows users
Windows users will need to go to https://mobaxterm.mobatek.net/, and download MobaXterm to use as your SSH client. We have created a quick guide on the basics of MobaXterm that you can read to get started in that environment. Please do this and then return to this walkthrough to continue.
Connecting to Gadi via terminal
Once you have an open terminal, you can connect to Gadi using the command line,
$ ssh <username>@gadi.nci.org.au
Replacing <username> with your MyNCI user name. e.g. aaa777, then enter your password.
At this point you should see something similar to the image on the right.
This means your login has been successful and you are now connected to one of Gadi's 10 login nodes.
Message of the day
We can immediately see a few messages that pop up on login, these are the messages of the day or MOTD.
This allows NCI to convey important messages about the system, accounts, and any upcoming maintenance to users. In the screenshot above we can see that on Mar 21 there was an expansion to the Gadi's CPU capacity and a link that you could copy for more information. There is also maintenance scheduled for Aug 1, which will impact jobs that run into the maintenance period.
NCI encourages users to read the MOTD at each log in to keep up to date with what is happening at NCI and with the Gadi system.
Graphical Tools
In order to run graphical tools on Gadi, you will need to enable an X-forwarding system on your local system when logging into ssh.
This can be done by running an X Server such as XQuartz on Mac, startx on Linux, or MobaXterm on windows.
If you are running MobaXterm, you might find that x-forwarding is already active at login.
One you have an X server running you can ssh to Gadi with the command:
$ ssh -Y <username>@gadi.nci.org.au
Again, replacing <username> with your own NCI username and entering your NCI password.
The -Y enables forwarding of trusted X protocol messages between your X-Server and Gadi's X programs, and we can see this in action by running a few tests.
First, let's try running a simple Graphics test by setting the display environment,
You can do this by running,
$ echo $DISPLAY
Which should return with a 'local host' if it has worked correctly.
We can then run two different tests to show that it is working.
1
We can run an X-Application called xeyes by running
$ xeyes
This should open the xeyes application that should look like this.
These eyes will follow your cursor around the monitor and are a great way to test if the graphical tools are working.
2
Another X-Application test is to run
$ xclock
This should open an analog clock displaying the current time. 
If these both work, you can be confident that X-forwarding is enabled on you session.
You may have the following issue when using XQuartz on MacOS:
$ xeyes connect /private/tmp/com.apple.launchd.VHwLfWsUSi/org.xquartz:0: Connection refused Error: Can't open display: localhost:28.0
The most probable reason is that it disabled the LaunchAgent for XQuartz.
If the following command:
$ launchctl getenv DISPLAY
prints nothing, then something is removing the LaunchAgent and the DISPLAY in your environment is stale (from when the LaunchAgent was loaded when you logged in).
You should investigate what is causing the LaunchAgent to get unloaded and stop that. You may check if you disabled it in "Login Items" in "System Preferences" or not.
Authors: Andrew Johnston
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