If you are are developing or testing the distributed system for automated grading, you may want to set up one or more worker machines in addition to your primary vagrant virtual machine.

Automated Worker Installation

These steps will create a worker machine alongside the normal Submitty machine.

  1. Make sure to destroy any existing vagrant machines with
    vagrant destroy
  2. Ensure you have Python 3 installed on your machine

  3. Generate configuration for the desired number of worker machines
    python3 generate_workers.py [-n NUM] [--ip-range IP_RANGE] [--base-port PORT]

    This will create or update a configuration file stored at .vagrant/workers.json. Now you can create the virtual machines with:

    vagrant up

    If you happen to encounter error messages regarding IP addresses or port conflicts, you can manually edit the workers.json file as needed.

    NOTE: Do not edit the workers.json configuration file or run the aforementioned python script if there are any existing vagrant machines in your project. This can result in the existing VMs continuing to run in the background or storing their data with no clean way to remove them.

  4. To delete the worker machines and revert to a normal development setup, you can first run
    vagrant destroy

    And confirm to delete all the existing virtual machines.

    Next, you can delete the workers.json file, which will remove the worker configuration from your project. The next vagrant up should only create the primary development virtual machine without any workers.

Connecting to the Worker Machine

If you would like to ensure the worker is functioning properly, or enter the worker machine for managing it directly, you can follow these steps.

To connect to a worker machine through SSH, run:

vagrant ssh <worker-name>

If you want to test the connection between the primary VM and a worker, you can first vagrant ssh into the primary machine and then run this command to SSH into the worker from there:

su submitty_daemon -c ssh submitty@<ip-address>

The IP address of the worker machine will be indicated in the .vagrant/workers.json file.

NOTE: Depending on the performance of your computer and the size of the autograding queue passed to the worker, the SSH command may hang for some time.

Manual Worker Installation (VirtualBox)

  1. Open the Virtual Box application.

  2. Click New to create a new machine. Give it a useful name: e.g., worker_machine_a Specify the type: Linux And the version: Ubuntu 64

  3. Specify the amount of memory: 2048 = 2GB should be sufficient.

  4. Create the disk as a new virtual disk. Specify RAM memory: 2048 (2GB) Create new virtual disk. Choose VDI Choose Dynamically allocated Specify size: e.g., 20GB

  5. Download the Ubuntu 22.04 installer 64 bit .iso. Save this somewhere on your host computer.

  6. Click on Start to power on. Browse your files to find the Ubuntu installer .iso we downloaded earlier. Press Start.

  7. Follow the Ubuntu installation menu… Click Install Ubuntu. Select English keyboard. Select normal installation. Agree to Erase disk & Install Ubuntu. Specify your timezone. Then specify your username, computer name, password. Then click through various menus, and wait a while installing system. Then restart the VM to finish installation.

  8. At some point, it will suggest that you install updates for Ubuntu 22.04, go ahead and do that. You’ll probably have to reboot.

  9. Allow ssh connections to the worker VM from outside (e.g., from your primary machine): from virtual box, select the VM, click on Settings, then Network, Enable Network Adapter should be checked, then set Attached to: Bridged Adapter

  10. From the VM, open a terminal and install a bunch of additional packages:

    sudo apt update
    sudo apt install net-tools
    sudo apt install openssh-server
    sudo apt install git
  11. Install Guest Additions (Improves screen resolution, copy paste to/from the VM, etc.)

    While the VM is running, focus on the VM window. Then from the menu, select Devices -> Insert guest additions CD image Open a terminal in the VM Go to the guest additions CD directory, and run the guest additions installer:

    cd /media/<USERNAME>/VBox_GAs_<VERSION>/
    sudo ./VBoxLinuxAdditions.run
  12. Get a permanent IP address for your machine Go to your router, assign a fix ip address for your mac address E.g., in a browser, go to and log in… Helpful command to find your mac address & current IP address:

  13. Prevent worker VM from going to sleep (so you can send autograding jobs to it at any time). Settings -> privacy -> screen lock -> turn off screen lock Settings -> power -> suspend & power button -> automatic suspend == off Settings -> power -> blank screen == never

  14. Follow the worker installation instructions