Obtain Resources: create a slice and reserve resources

Introduction: Getting Started with GENI and the GENI Portal



Now that you are a member of a project, you can create a slice and reserve resources.

4. Create a slice

If you are following on from the Getting Started with GENI I tutorial, and the slice you created then has not yet expired, you can reuse the same slice -- skip ahead to step 2 (Import a simple experiment).

Otherwise, you will need to create a new slice, which can be done through the GENI Portal, as follows:

Create a GENI Slice
  1. Go to the Home tab.
  2. Press the Create Slice button for this project.
  3. As a slice name use the slice name on your worksheet (the slice name should be of the form portal##), you can leave the description empty and press Create Slice

4.1. Import a simple experiment

For this exercise, we will start with a prepared rspec file.

You should load this topology into Flack:

  1. From the "Import" menu (see figure), select the "Import from the web" item.
  2. Enter the URL corresponding to the rack type you are using and open it:


  3. Because this file contains a generic description of resources and does not specify any particular aggregate manager, Flack will report "There were resources detected without a manager selected, please select which manager you would like to use." Select "OK", and then choose the manager listed on your worksheet from the list. Then select "Accept", and a network topology (which might look familiar if you have completed earlier tutorials) should appear on the canvas.

4.2. Modify the experiment to automatically install and execute network test software

1. For this sample experiment, we'd like some additional software (Apache, iperf, and a couple of custom scripts) loaded onto the VMs to perform traffic measurements. In Flack, you can manipulate the details of the request for a node or link with the "i" button on the relevant component on the canvas (see figure). Do this now on the client node.

2. When you open the node information, you should see options like those in the figure. The controls available to you will vary depending on the types of the aggregate manager and the component, but many features are widely available throughout GENI.

3. The way we will request installation of the proper software and execution of our experiment is to add install and execute services. First, select "+ Add Install Service" as shown. Flack will now prompt you for an "Archive URL" and a location for installation. For this experiment, please enter the appropriate URL:


and ask for this to be installed in:

4. Similarly, please use the "+ Add Execute Service" button to request that the appropriate command:


sudo /local/


(client node only)
(server node only)

be executed using

Be very careful when entering this information -- these commands will not be executed yet, so it will be some time before you will see any relevant error messages if there is a mistake here.

5. Once both the "install" and "execute" services are specified, please choose "Apply". Then repeat the procedure to add the same "install" and "execute" services on the server node.

If you have time, it would be instructive to download the "gec17tut2.tar.gz" file yourself, and inspect the contents. You will see the file referred to in the execute service, and this is a good example of how you can ask for GENI components to perform tasks for you without any manual intervention. This is a very useful facility for large experiments!

4.3. Export the modified request RSpec

Now we will pull back some of the covers and inspect exactly what Flack has been doing for us when preparing the rspecs for the experiments we design. Each node and link has a corresponding element in the rspec, and the details of the component configuration (such as the install and execute services we requested above) are specified with attributes, or sometimes child elements, within those portions of the document.

  1. From the "View" menu (see figure), select the "Preview request document(s)" item. This will bring up a window showing the current rspec -- please take a moment to inspect it. The XML elements under the "flack" namespace were added for Flack's internal use (containing information about the canvas layout, editing history, etc.), and are ignored by aggregate managers. The "node" and "link" elements contain the specification for the components we will request, and if you look closely, you will be able to see the install and execute service elements you added earlier.
  2. Use the "Save to file" button (in the upper left) to make a local copy of your rspec. We'll use this in the next step to demonstrate how other client tools also use rspec files to communicate requests to aggregate managers.

5. Instantiate the new experiment using Omni

For this step, we'll change the approach a bit and switch to a new client tool: the command line Omni client. From a terminal, please enter the command:


where AM_NICKNAME is the nickname for your assigned aggregate manager and SLICENAME is the name of the slice you created at the portal (both of these are given on your worksheet). RSPEC_FILE should be replaced with the filename of the rspec you saved in step 4.

If all is well, Omni should give you a number of informational messages, such as:

INFO:omni:Loading config file /home/geni/.gcf/omni_config

It should quickly proceed to the point where it makes the request to the remote manager:

INFO:omni:Creating sliver(s) from rspec file /home/geni/Downloads/experiments.rspec for slice ...

This step can sometimes be time-consuming, so please be patient. If it succeeds, within a few minutes Omni should report:

INFO:omni: Completed createsliver:

and your sliver is complete!

Next: Inspect the experiment execution

Last modified 9 years ago Last modified on 07/19/13 23:51:44