Orbit > HowToGetStarted

How to get started

First, you need an account. Please check the UsagePolicy if you are eligible. In order to get an account please ​register here.

A typical experiment requires the following three steps:

• Reservation
• Running the experiment
• Analyzing the results

Running the Experiment

During your approved time slot, you will be able to ssh into the console of the respective grid. A console is a dedicated machine that allows access to all resources on that grid.

Currently, this requires a two step process.

• You first need to log into gateway.orbit-lab.org with your Orbit credentials using ​SSH.
• During your approved time slot, you can then log into the console corresponding to the following table using SSH:

Main grid (400 nodes)	console.grid.orbit-lab.org
Sandbox 1 (2 nodes)	console.sb1.orbit-lab.org
Sandbox 2 (2 nodes)	console.sb2.orbit-lab.org
Sandbox 5 (2 nodes)	console.sb5.orbit-lab.org
Sandbox 6 (2 nodes)	console.sb6.orbit-lab.org
Sandbox 7 (2 nodes)	console.sb7.orbit-lab.org

For e.g to access the sandbox2,

yourhost>ssh username@gateway.orbit-lab.org

gateway> ssh username@console.sb2.orbit-lab.org

When you have successfully logged in, you can start an experiment using the nodehandler. First time users are highly encouraged to reserve time on a sandbox instead of the main grid, and start with the built-in Hello World experiment.

• Prior to the experiment, users need to install the baseline image on the hard disks of the nodes. This process will soon be done by the system before a slot is approved so that users can directly start the experiment with their preferred image on the nodes

After the imaging process is complete as shown in the figure below, users can now run the Helloworld experiment.

The experiment can be started with:

user#> nodehandler -t

• This experiment will send UDP datagrams of 1024 bytes from node 1-1 to node 1-2 at 300 kbps CBR traffic.
• Both, sender and receiver, report measurements to a database, using our OML measurement framework.
• As shown below, the experiment controller will power on the nodes involved in the experiment and will issue experiment commands to each node.
• Each experiment has a unique experiment ID as shown in the figure, that can be used later to view the results from the database

Alternatively, a specific script can be run as follows:

The experiment can be started with:

user#> nodehandler <full-path/script-name>

For e.g., if my script is called orbit-test.rb and it resides in /home/joenull/Ruby-Scripts/ (ORBIT home directory), I would execute it as follows:

user#>pwd
/home/joenull
user#>nodehandler ~/Ruby-Scripts/orbit-test 

Note that I leave out the ".rb" at the end. This will execute the scripts and turn the nodes OFF at the end of the experiment. If you want to leave them ON after the experiment, use the "-k" flag. For e.g.

user#>pwd
/home/joenull
user#>nodehandler -k ~/Ruby-Scripts/orbit-test 

The experimenter can also move to the where the script resides and execute it (without giving the full path) since nodehandler will look for the script in the current directory.

More information on writing experiment scripts can be found in the Tutorial.

Analyzing Results

Orbit provides a sophisticated framework to efficiently collect measurements at runtime into a database. This database is accessible to the experimenter during the experiment from the console. At the end of an experiment, the database is copied to an external machine and is accessible without a reservation. More information can be found here.

Where to go from here

If you are still unsure what Orbit is, please read the FAQ and the Tutorial, otherwise go ahead and register.