On this page:
8.1 Creating a profile from an existing one
8.1.1 Preparation and precautions
8.1.2 Cloning a Profile
8.1.3 Copying a Profile
8.1.4 Creating the Profile
8.1.5 Updating a profile
8.2 Repository-Based Profiles
8.2.1 Updating Repository-Based Profiles
8.2.2 Branches and Tags in Repository-Based Profiles
8.3 Creating a profile from scratch
8.4 Sharing Profiles
8.5 Versioned Profiles
2024-01-04 (93db12d)

8 Creating Profiles

When you create a new profile, you are creating a new RSpec, and, usually, creating one or more disk images that are referenced by that RSpec. When someone uses your profile, they will get their own experiment that boots up the resources (virtual or physical) described by the RSpec. It is common to create the resource specifification for profiles by writing a python script rather than dealing with RSpecs directly.

8.1 Creating a profile from an existing one

The easiest way to create a new profile is by cloning or copying an existing one and customizing it to your needs. The basic steps are:

When you clone an experiment, you are taking an existing experiment, including a snapshot of the disk, and creating a new profile based on it. The new profile will be identical to the profile that experiment was based on in all other respects. Cloning only works on experiments with a single node.

If you copy a profile, you are creating a new profile that is identical in every way to an existing profile. You may or may not have a running experiment using the source profile. And if you do have a running experiment, it does not impact the copy. After copying a profile, you can then modify it for your own use. And if you instantiate the copy, you can then take snapshots of disk images and use them in future version of your copy. Any profile that you have access to may be copied.

8.1.1 Preparation and precautions

To create profiles, you need to be a registered user.

Cloning a profile can take a while, so we recommend that you extend your experiment while creating it, and contact us if you are worried your experiment might expire before you’re done creating your profile. We also strongly recommend testing your profile fully before terminating the experiment you’re creating it from.

When cloning, your home directory is not included in the disk image snapshot! You will need to install your code and data elsewhere in the image. We recommend /local/. Keep in mind that others who use your profile are going to have their own accounts, so make sure that nothing in your image makes assumptions about the username, home directory, etc. of the user running it.

When cloning, be aware that only disk contents (not running process, etc.) are stored as part of the profile, and as part of the creation process, your node(s) will be rebooted in order to take consistent snapshots of the disk.

For the time being, cloning only works for single-node profiles; we will add support for multi-node profiles in the future.

When copying a profile, remember that the disk images of a currently running experiment are not saved. If you want to customize the disk images using copy, you must copy the profile first, then instantiate your copy, then take snapshots of the modified disk image in your experiment.

8.1.2 Cloning a Profile
  1. Create an experiment
    Create an experiment using the profile that is most similar to the one you want to build. Usually, this will be one of our facility-provided profiles with a generic installation of Linux.

  2. Set up the node the way you want it
    Log into the node and install your software, datasets, packages, etc. Note the caveat above that it needs to be installed somewhere outside of your home directory, and should not be tied to your user account.

  3. Clone the experiment to create a new profile
    While you are logged in, the experiment page for your active experiments will have a “clone” button. Clicking this button will create a new profile based on your running experiment.
    Specifically, the button creates a copy of the RSpec used to create the experiment, passes it to the form used to create new profiles, and helps you create a disk image from your running experiment.

  4. Create Profile
    You will be taken to a complete profile form and should fill it out as described below.

8.1.3 Copying a Profile
  1. Choose a profile
    Find the profile you wish to clone using the “Start Experiment” selector. Then you can click “Show Profile” to clone the profile directly or you can instantiate the profile if you wish to create an experiment first. Both profiles themselves and active experiments can be copied.

  2. Copy the profile or experiment
    While logged in, both your experiment page and the show profile page will have a copy button. Clicking this button will create a profile based on that profile or experiment.
    This button only copies the rspec or genilib script. No state in the active experiment is preserved.

  3. Create Profile
    You will be taken to a complete profile form and should fill it out as described below.

8.1.4 Creating the Profile

After copying or cloning a profile (see above) or selecting the menu option to create a new profile from scratch, you will need to fill out the profile creation form in order to complete the creation process.

  1. Fill out information for the new profile
    After clicking on the “clone” button, you will see a form that allows you to view and edit the basic information associated with your profile.
    Each profile must be associated with a project. If you’re a member of more than one project, you’ll need to select which one you want the profile to belong to.
    Make sure to edit the profile’s Description and Instructions.
    The “Description” is the text that users will see when your profile is listed in Powder, when the user is selecting which profile to use. It is also displayed when following a direct link to your profile. It should give the reader a brief description of what they will get if they create an experiment with this profile. If the profile is associated with a paper or other publication, this is a good place to mention that. Markdown markup, including hyperlinks, are allowed in the profile description.
    The “Instructions” text is displayed on the experiment page after the user has created an experiment using the profile. This is a good place to tell them where the code and data can be found, what scripts they might want to run, etc. Again, Markdown is allowed.
    The “Steps” section allows you to create a “tour” of your profile, which is displayed after a user creates an experiment with it. This feature is mostly useful if your profile contains more than one node, and you wish to explain to the user what the purpose of each node is.
    You have the option of making your profile usable to anyone, only registered Powder users, or members of your project. Regardless of the setting you chose here, Powder will also give you a direct link that you can use to share your profile with others of your choosing.

  2. Click “Create”
    When you click the “Create” button, your node will be rebooted, so that we can take a consistent snapshot of the disk contents. This process can take several minutes or longer, depending on the size of your disk image. You can watch the progress on this page. When the progress bar reaches the “Ready” stage, your new profile is ready! It will now show up in your “My Profiles” list.

  3. Test your profile
    Before terminating your experiment (or letting it expire), we strongly recommend testing out the new profile. If you elected to make it publicly visible, it will be listed in the profile selection dialog on the front page of https://www.powderwireless.net/. If not, you can instantiate it from the listing in your “My Profiles” page. If the profile will be used by guest users, we recommend testing it as one yourself: log out, and instantiate it using a different username (you will also have to use an alternate email address.

  4. Share your profile
    Now that your profile is working, you can share it with others by sending them direct links, putting links on your webpage or in papers, etc. See “Sharing Profiles” for more details.

8.1.5 Updating a profile

You can update the metadata associated with a profile at any time by going to the “My Profiles” page and clicking on the name of the profile to go to the profile page. On this page, you can edit any of the text fields (Description, Instructions, etc.), change the permissions, etc.

As with cloning a profile, this snapshot feature currently only works with single-node profiles.

If you need to update the contents of the disk image in the profile, simply create a new experiment from the profile. (You will only see this button on experiments created from profiles that you own.) Once your experiment is ready, you will see a “Snapshot” button on the experiment page. Log into your node, get the disk changed the way you want, and click the button.


This button kicks off the same image creation process that occurs during cloning a profile. Once it’s finished, any new experiments created from the profile will use the new image.

As with creating a new profile, we recommend testing the profile before letting your experiment expire. If something goes wrong, we do keep one previous image file for each profile; currently, the only way to get access to this backup is to contact us.

8.2 Repository-Based Profiles

You can turn any public git repository (including those hosted on GitHub) into a Powder profile. Simply place a geni-lib script named profile.py into the top-level directory of your repository. When you create a new profile, you can provide the URL for your repository. The URL needs to be a http:// or https:// URL, and the CloudLab portal needs to be able to clone the repository without authentication.

Note that CloudLab is not a git hosting service; while we do keep a cache of your repository, we don’t guarantee that the profile will continue to work if the original repository becomes unavailable. We also have limits on the size of the repositories that we will clone.

When you instantiate a repository-based profile, the repository will be cloned into the directory /local/repository on all nodes in the experiment. This means that you can keep source code, startup scripts, etc. in your repository and reference them from profile.py. Powder sets the pull URL for all of these clones to be your “upstream” repository, and attempts to set a suitable push URL for (it assumes that the hosting service uses ssh for pushes, and uses the git@<hostname>:user/repo convention). As a result, git pull and git push should be connected to your repository.

There is an example repository on GitHub at https://github.com/emulab/my-profile; if you don’t already have a git repository created, a good way to get started is to fork this one and create a new profile pointing at your fork.

Pushing to your repository is still governed by the authentication and permissions of your git hosting service, so others using your profile will not be able to push to your repository.

8.2.1 Updating Repository-Based Profiles

By default, the CloudLab profile does not automatically update whenever you push to your upstream repository; this means that people instantiating your profile see the repository as it existed at the time Powder last pulled from it.

You can manually cause Powder to pull from your repository using the “Update” button on the profile management page.

You can also set up Powder to automatically pull from your repository whever it is updating. To do so, you will need to set up a “web hook” on the service that hosts your git repository. Powder currently supports webhooks for GitHub.com, BitBucket.org, and sites hosted using GitLab (including both GitLab.com and self-hosted GitLab installations.) See the “push URL” in the Repository Info panel on the left side of the profile page for the webhook URL, and use the “information” icon next to it to get specific instructions for setting up a webhook on each service. Once you have set the webhook up, every time you push to your repository, your hosting service will let Powder know that it should automatically initiate a pull. (This will not be instantaneous, but should complete quickly in most cases.)

8.2.2 Branches and Tags in Repository-Based Profiles

By default, repository-based profiles will be instaniated from the master branch. At the bottom of the profile page, you will also find a list of all branches and tags in the repository, and can instantiate the version contained in any of them. Branches can be used for development work that is not yet ready to become the master (default) version of the profile, and tags can be used to mark specific versions of the profiles that were used for specific papers or course assignments, for example.

8.3 Creating a profile from scratch

Powder profiles are described by GENI RSpecs. You can create a profile directly from an RSpec by using the “Create Profile” option from the “Storage” menu. Note that you cannot edit the text fields until you upload an RSpec, as these fields edit (in-browser) fields in the RSpec.

8.4 Sharing Profiles

If you chose to make your profile publicly visible, it will show up in the main “Select Profile” list on https://www.powderwireless.net/. Powder also gives you direct links to your profiles so that you can share them with others, post them on your website, publish them in papers, etc. The link can be found on the profile’s detail page, which is linked for your “My Profiles” page. If you chose to make your profile accessible to anyone, the link will take the form https://www.powderwireless.net//p/<project-id>/<profile-id>. If you didn’t make the profile public, the URL will have the form https://www.powderwireless.net//p/<UUID>, where UUID is a 128-bit number so that the URL is not guessable. You can still share this URLs with anyone you want to have access to the profile—for example, to give it to a collaborator to try out your work before publishing.

8.5 Versioned Profiles

Profiles are versioned to capture the evolution of a profile over time. When updating profiles, the result is be a new version that does not (entirely) replace the profile being updated.

When sharing a profile, you are given two links to share. One link will take the user to the most recent version of the profile that exists at the time they click the link. This is the most appropriate option in most cases. There is also a link that takes one to a specific version of the profile. This link is most useful for publication in papers or other cases in which reproducability with the exact same environment is a concnern.