Released: 01/14/2025
Due: 01/23/2025

• Overview
• Register a CloudLab Account
• Start an Experiment
• Tasks
  • Part 1: Check for the Available Resources
  • Part 2: Create a virtual network with Kathará
  • Deliverable
• Policies on Using CloudLab Resources

Overview

You will do your assignments for CS 356 using CloudLab and Kathara. CloudLab is a research facility that provides bare-metal access and control over a substantial set of computing, storage, and networking resources. If you haven’t worked in CloudLab before, you need to register a CloudLab account. Kathara is a network emulation tool that enables you to test your network programs without multiple physical servers and network devices. This small assignment walks you through the CloudLab registration process and shows you how to start an experiment in CloudLab. In addition, you will try out Kathara. You should submit a per-group report that shows you have successfully followed the process. Most importantly, it introduces our policies on using CloudLab that will be enforced throughout the semester.

NOTE: $ [shell_command] indicates to execute [shell_command] in your terminal.

Register a CloudLab Account

• Visit CloudLab and create an account using your UT Austin email address as an email.
  • Select Join Existing Project and enter utcs356.
  • Fill out your information. Use your UT email address as an email.
  • Create ssh key pair and upload your public key during the account setup.
    Ubuntu and macOS

    1. Install OpenSSH
       macOS: $ brew install openssh
       Ubuntu: $ sudo apt-get install openssh-client openssh-server
    2. Generate a key pair with ssh-keygen
       You can use the below example as it is or try other cryptographic algorithms you prefer (see man ssh-keygen)
       Example: $ ssh-keygen -t rsa -b 4096
    3. Type enter without typing any character when the prompt asks for the file path and passphrase.
       • If you want to save your keys other than the default location, enter a file path (e.g., ~/foo/mykey) to save your private key when the prompt asks for it.
       • If you want additional security, type a passphrase when the prompt asks for it.
    4. The private key will be saved into the default location, ~/.ssh/id_rsa. ~/.ssh/id_rsa is your private key and ~/.ssh/id_rsa.pub is your public key (upload this during the account registration).
       • If you specified a custom file path, your private and public keys will be located at the path you provided (e.g., ~/foo/mykey for the private key and ~/foo/mykey.pub for the public key).
    Windows

    • Check if OpenSSH Client is installed. (Windows 10 only)
      1. Open the Windows 10 Start menu and search for Apps & Features. In the Apps & Features heading, click Optional Features.
      2. Scroll down the list to see if OpenSSH Client is listed. If not, click the plus sign next to Add a feature, select OpenSSH Client, and click Install.
    • Generate a ssh key pair.
      1. Press the Windows key or open up the Start Menu. Type cmd.
      2. Under Best Match, click Command Prompt.
      3. In the command prompt, generate a key pair with ssh-keygen You can use the below example as it is or try other cryptographic algorithms you prefer (see man ssh-keygen)
         Example: $ ssh-keygen -t rsa -b 4096
      4. Type enter without typing any character when the prompt asks for the file path and passphrase. If you want to save your keys other than the default location, enter a file path to save your private key. If you want additional security, type a passphrase when the prompt asks for it.
      5. Open your file explorer. You can now navigate to the hidden .ssh directory in your home folder (C:\Users\[Username]). You should see two new files. The identification is saved in the id_rsa file and the public key is labeled id_rsa.pub. Upload the public key during the account registration.
    • Source: link
• If you already have an account, click your username at the top right corner and then select Start/Join Project and type utcs356 into the ProjectID field.

Once you complete the above steps, the instructor or TA will approve your request to join the project so that you can start an experiment.

Start an Experiment

An experiment in CloudLab means the instantiation of a profile. You can think of a profile as a pre-configured VM image that includes OS and necessary setup. An experiment lasts only for the reserved hours, and all the changes you made on top of the profile will be discarded. Make sure that you use a private git repository to save your code.

1. To start a new experiment, go to your CloudLab dashboard and click the Experiments tab in the upper left corner. Then select Start Experiment, moving to the profile selection panel.
2. Click Change Profile.
3. Select a profile from the list. Choose the cs356-base profile in the utcs356 project. With this profile, you can launch one machine with the Ubuntu 22.04.2 LTS image with Docker and Kathara additionally installed.
4. Click Next to move to the next panel (Parameterize).
5. Click Next to move to the next panel (Finalize). You don’t need to parameterize an experiment unless explicitly mentioned.
6. Here, you should name your experiment with CSLogin1-CSLogin2 (CSLogin1 is the cs username of Member 1), select utcs356 as Project, and your assignment group as Group (You will be invited. If you’re not yet invited, Group might not appear. You’re ok to proceed without selecting Group for this assignment). You need to specify from which cluster you want to start your experiment. Please select the Wisconsin cluster. If it fails, then try another cluster except for the Utah cluster. Click Next to move to the next panel (Schedule).
7. Enter the desired experiment duration and the time/date when you want to start the experiment. If you want to start your experiment as soon as possible, skip the Start on date/time field. Once your experiment is ready you will receive a notification email.

8. You can navigate to your CloudLab user dashboard to see your list of active experiments. You will move to a webpage describing project details by clicking on the experiment name. Click the List View on that page, which opens a table where you can obtain the SSH login command (ssh <cloudlab_id>@<cloudlab_host>) to log in to your machine. Ensure that the status of your experiment is “Ready” before attempting to access it via SSH. It may take approximately 10 minutes for the experiment to reach the ready state.

9. Try to login to the machine by executing the provided SSH command in your terminal. This step will only work if you have uploaded your SSH public key to your CloudLab account. Add your public key if you did not add it during the registration (here).
   • $ ssh <cloudlab_id>@<cloudlab_host>
   • If you specified a custom file path while creating your SSH key pair, try: $ ssh -i <private_key_path> <cloudlab_id>@<cloudlab_host>.
   • You may want to setup remote development on VSCode. Make sure the above ssh command works before VSCode setup.
   VSCode setup

   1. Install the Remote-SSH extension.
   2. In VS Code, select Remote-SSH: Connect to Host... from the Command Palette (F1) and use the same <cloudlab_id>@<cloudlab_host> as in the above ssh command.
   3. If VS Code cannot automatically detect the type of server you are connecting to, you will be asked to select the type manually. Select Linux.
   4. You can then open any folder or workspace on the remote machine using File > Open... or File > Open Workspace... just as you would locally!

   Refer to the link for more detailed instructions.

If you find yourself stuck on any of the above steps, don’t hesitate to post your questions to Ed!

Tasks

Part 1: Check for the Available Resources

Check the number of physical CPU cores, logical cores (threads), and available memory on the node you reserved using the following commands:

• CPU information: $ lshw -class cpu or $ lscpu
• Memory information: $ free -h

Include the resource details from these commands in your report.

Part 2: Create a virtual network with Kathará

Throughout the assignments, we will use Kathará, an open-source container-based network emulation system. With the network emulation tools like Kathará, we can test (network) applications without multiple servers and network devices. In Kathara, you can create a virtual network consisting of multiple virtual network devices by launching a Kathara lab. A Kathara lab directory in which you launch the lab defines a virtual network to be created.

1. Setup

After ssh to the reserved node, type the command below.

$ sudo usermod -aG docker $USER

Then restart the SSH session to make sure the changes are applied.

2. Launch a Kathara lab to create a virtual network

Run the below commands. The below will launch a virtual network defined in the Kathara lab directory, assignment1/labs/two_hosts_direct/.

$ git clone https://github.com/utcs356/assignment1.git  
$ cd assignment1/labs/two_hosts_direct  
$ kathara lstart  

If you encounter any warnings or errors related to xterm when executing the above commands, please disregard them.

3. Connect to the virtual network devices generated by Kathara

There are two virtual network devices in this Kathara lab, h1 and h2. Create two separate terminals with tmux. tmux allows you to create multiple terminals without multiple SSH connections. Expand the below for its usage.

In each terminal, connect to each device with $ kathara connect <device_name> (e.g., $ kathara connect h1). Make sure you launch the command in the lab directory.

4. Check the virtual network devices

Run $ ifconfig (man ifconfig) to identify the network interfaces and their IP addresses on each device (terminal). Report the IP address of the network interface attached to each device in your report. Please include a screenshot showing the outputs of ifconfig from both devices displayed within a single tmux window.

5. Clean up the Kathara lab

Don’t forget to run $ kathara lclean in the lab directory when you’re done with your lab.

NOTE: You should follow these steps to run a Kathará lab throughout the assignments.

Deliverable

For each group, submit a report in a pdf file named assign0_groupX.pdf, where X is your group number. Make sure to include your group number, names, and EIDs in the report.

Policies on Using CloudLab Resources

• Please read and follow Cloudlab’s Acceptable Use Policy.
• CloudLab gives users 16 hours to start with, and users can extend it longer. You can manage your time efficiently and only hold onto those nodes when working on the assignment.
• You should use a private git repository to manage your code and terminate the nodes when you are not using them. If you do need to extend the nodes, do not extend them by more than one day. We will terminate any cluster running for more than 48 hours.
• As a member of the utcs356 project, you have permission to create new experiments in the default group in addition to the group you are invited to. Stick to your own group and use naming formats as mentioned. For more information related to this, please refer to this.
• Each cluster has different hardware. For more information on CloudLab’s hardware, please refer to this.