A holistic testbed/emulator for the book: Computing in Communication Networks: From Theory to Practice

This project is currently under heavy development [beta].

For all ComNetsEmu users:

Please run the upgrade process described here when there is a new release published here. New features, fixes and other improvements require running the upgrade script manually. But the script will check and perform the upgrade automatically and it does not take much time if you have a good network connection. Check the CHANGELOG for information of new releases.

• Description
  • Main Features
• Installation
  • Option 1: Install in a Vagrant managed VM (Highly Recommended)
  • Option 2: Install on user's custom VM or directly on host OS
  • Post-Installation
• Upgrade ComNetsEmu and Dependencies
• Run the Docker-in-Docker example
• File Catalog
• Development Guide and API Documentation
• FAQ
• Useful Links
• Contributing
• Contact

ComNetsEmu is a testbed and network emulator designed for the NFV/SDN teaching book "Computing in Communication Networks: From Theory to Practice". The design focus on emulating all examples and applications on a single computer, e.g. on a single laptop. ComNetsEmu extends the famous Mininet network emulator to support better emulation of versatile Computing In The Network (COIN) applications. It extends and puts forward the concepts and work in the Containernet project. It uses a slightly different approach to extend the Mininet compared to Containernet. It's main focus is to use "sibling containers" to emulate network systems with computing. See the detailed comparison between upstream Mininet and Containernet here.

Common facts about ComNetsEmu:

• Emulation performance is considered but not the main focus. All emulated nodes (processes) share the same underlying compute, storage and network resources when running it on a single system. ComNetsEmu is heavier than vanilla Mininet due to complete host isolation. Chose a reasonable performance limitation is recommended for better emulation results. For example, use e.g. 100ms as link delay instead of 1ms for large scale topology.

• ComNetsEmu is developed with Python3.6. To reduce the complexity of dependencies (third-party packages, frameworks etc.), ComNetsEmu tries to leverage as much of the powerful Python standard library as possible, and prefers simple third-party dependencies when necessary.

• Examples and applications in this repository are mainly developed with high-level script language for simplicity. These programs are not performance-oriented and optimized. Contact us if you want highly optimized implementation of the concepts introduced in this book. For example, we have DPDK accelerated version (implemented with C) for low latency (sub-millisecond) Network Coding (NC) as a network function.

• Use Docker hosts in Mininet topologies.

• Manage application Docker containers deployed INSIDE Docker hosts. "Docker-in-Docker"(sibling containers) is used by ComNetsEmu as an lightweight emulation for nested-virtualization. The Docker host with internal Docker containers deployed is used to mimic an actual physical host that runs Docker containers.

• A collection of application examples for "Computing In Communication Networks" with sample codes and detailed documentation. All examples can be easily reproduced and extended.

Check the Roadmap for planed and WIP features.

Supported/Tested distributions:

1. Ubuntu 18.04 LTS (Bionic Beaver): Used as base-box in the Vagrant VM.
2. GNU/Debian 10 (Buster)

For development and using it as a playground, it is recommended to run ComNetsEmu INSIDE a VM. Run ComNetsEmu/Mininet application requires root privilege, hacking it inside a VM is also safer. ComNetsEmu's installation script uses Mininet's install script to install Mininet natively from source. As described in Mininet's doc, the install script is a bit intrusive and may possible damage your OS and/or home directory. It is recommended to trying and installing ComNetsEmu in a VM. It runs smoothly in a VM with 2 vCPUs and 2GB RAM. (Host Physical CPU: Intel i7-7600U @ 2.80GHz). Some applications require more resources. For example, the object detection application requires minimal 4GB RAM.

Firstly, clone the repository with git. $TOP_DIR is the directory that you want to download the ComNetsEmu's source code. In Vagrant VM, TOP_DIR="$HOME". ComNetsEmu's installer (BASH scripts) assumes the name of the source directory is comnetsemu and will download external source dependencies in $TOP_DIR/comnetsemu_dependencies.

$ cd $TOP_DIR
$ git clone https://git.comnets.net/public-repo/comnetsemu.git comnetsemu

ComNetsEmu's installer tries to install dependencies with package manager (apt, pip etc.) if they are available. Unavailable dependencies (e.g. latest stable Mininet) are installed from source code. The source codes are downloaded into "$TOP_DIR/comnetsemu_dependencies" directory by default (It does not use a subdirectory inside the ComNetsEmu's source due to a file-permission issue of Vagrant (v2.2.5)). The installer also checks the status of the dependency directory when upgrading is performed. The ComNetsEmu's installer script is designed mainly for easy/simple setup/upgrade of the Vagrant VM environment.

Here is a list of dependencies required by ComNetsEmu, these tools can be installed and updated by ComNetsEmu's installer.

The comfortable way to setup the test and development environment is to run a pre-configured VM managed by Vagrant. Vagrant supports multiple providers including Virtualbox and Libvirt (With vagrant-libvirt plugin). Most examples and applications included in this repository can run on Virtualbox which is cross-platform. Therefore, you host OS can be any OS that supports Virtualbox (GNU/Linux, Windows and Mac OS etc.).

Mainly due to the performance and special feature requirements, some examples and applications can run ONLY on VM with KVM as the hypervisor:

1. machine_learning_for_routing
2. machine_learning_for_congestion_control (Will be added soon)

In order to run these programs, your host OS must use Linux kernel. You can install a GNU/Linux distribution on your physical machine. WARN: Two providers can not be used at the same time. Same VM can be created either by Virtualbox or KVM.

Recommended and tested setup:

• Vagrant: v2.2.5 (Download Link)
• Virtualbox: v6.0 (Download Link)
• (Optional) Libvirt: v5.10 (Download Link)
• (Optional) Vagrant Libvirt Provider: v0.0.45 (Download Link)

Warning: The latest version of Virtualbox/Libvirt may not work properly with latest Vagrant. For example, the Vagrant 2.2.6 does not fully support Virtualbox 6.1. (see the issue here) Therefore, it is recommended to use tested versions listed above and the ComNetsEmu dev team will update the recommended versions after tests.

A customized Vagrantfile is provided in this repository to manage the VM. Both Virtualbox and Libvirt can be used to create the VM. The default provider is Virtualbox. Different providers uses different base boxes, please check the Vagrantfile for details. You can choose the provider with --provider option of the vagrant up command.

• Some Known Issues

Please follow the documentation to setup the VM with proper resource allocation. If the vagrant up command fails to setup the VM fully correct which you can test by running the basic Docker-in-Docker example. Please firstly check the known VM setup issues for potential solutions.

• VM Resource Allocation (Important)

By default, this VM is allocated with 2 vCPUs and 4GB RAM to run all examples and applications smoothly. If you machine does not have enough resources, you need to change the variable CPUS and RAM in the Vagrantfile before created the VM. Some applications (e.g. machine_learning_for_object_detection) require minimal 4GB RAM to run smoothly without crash. That's the only reason why this resource allocation is used by default.

• Use Virtualbox as Provider

To manage the Virtualbox VM, please open a terminal on your host OS and change the working directory to the directory containing the ComNetsEmu's source code. Use following commands to manage the VM.

# This will create the VM at the first time (takes around 20 minutes)
$ vagrant up comnetsemu

# SSH into the VM
$ vagrant ssh comnetsemu

# Poweroff the VM
$ vagrant halt comnetsemu

# Remove/Delete the VM
$ vagrant destory comnetsemu

• Use Libvirt as Provider

To create the VM with Libvirt provider. Check the guide to install the plugin.

After successful installation, run the following command in the ComNetsEmu's source directory:

$ vagrant up --provider libvirt comnetsemu
# Remove the VM managed by libvirt, the default provider is Virtualbox. Use VAGRANT_DEFAULT_PROVIDER to force vagrant to
# use libvirt.
$ VAGRANT_DEFAULT_PROVIDER=libvirt vagrant destroy comnetsemu

Rsync mode is used in the Libvirt provider for unidirectional (host->guest) sync. The syncing does not automatically start after the vagrant up. Open a shell and run $ vagrant rsync-auto comnetsemu after the VM is booted to start syncing. For bidirectional sync, NFS need to be configured and used as the sync type.

• Customization Shell Script

A customization shell script (should be located in ./util/vm_customize.sh) is executed at the end of the provision process. This script is executed by the vagrant user which can run sudo commands without password. This script can be used to add your customized tools (e.g. ZSH, Desktop environment etc) and configuration to the ComNetsEmu VM. Since the vagrant VM uses Ubuntu 18.04 LTS, apt should be used to manage the packages.

Example of vm_customize.sh:

sudo apt install -y zsh
# Install oh-my-zsh framework
sh -c "$(wget -O- https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"

The vagrant up should run correctly. If there are some "apt" or "dpkg" related error messages (like some packages can not be found or installed) during the vagrant up, it might due to the box you used to build the VM is outdated. It is configured in current ./Vagrantfile that the vagrant will check if there are any updates to the box used in the current environment. It can be checked manually with vagrant box update. You need to destroy the already built VM and recreate it to acquire the new updates in the box with:

$ vagrant box update
$ vagrant destory comnetsemu
# This will create the VM at the first time (takes around 15 minutes)
$ vagrant up comnetsemu

As configured in ./Vagrantfile, current source code folder on the host OS is synced to the /home/vagrant/comnetsemu folder in the VM. And the emulator's Python package is installed in development mode. So you can work on the emulator or application codes in your host OS and run/test them in the VM.

As described in here, installation on user's custom VM or directly on the host OS has several disadvantages. It is not convenient to manage the test environment compared to the option 1. For this option, it is recommended to install Ubuntu 18.04 LTS freshly inside the VM or as the host OS to avoid potential package conflicts. Currently, this option is not well-tested compared to the option 1.

Supported/Tested distributions:

1. Ubuntu 18.04 LTS (Bionic Beaver): Used as base-box in the Vagrant VM.
2. GNU/Debian 10 (Buster)

• Install essential packages required by the installer from your package management systems:

$ sudo apt update
$ sudo apt upgrade
$ sudo apt install git make pkg-config sudo python3 libpython3-dev python3-dev python3-pip software-properties-common

• Install ComNetsEmu with all dependencies:

$ cd $TOP_DIR/comnetsemu/util
$ bash ./install.sh -a

MARK: ComNetsEmu is developed with Python3 (3.6). Please use python3 command to run examples or applications. Because the current master branch is still under heavy development, therefore this python3 package can be only installed from source using setuptools.

ComNetsEmu uses Docker containers to emulate network nodes. Some images are used to run hosts and app containers in examples and also applications. The Dockerfiles for external Docker hosts are located in ./test_containers.

Please build them after the installation and re-build them after updates by running the script:

$ cd ./test_containers
# This script removes all dangling images after build.
$ bash ./build.sh

Example screenshots for running the upgrade process in terminal:

The master branch contains stable/tested sources for ComNetsEmu's python package, utility scripts, examples and applications. It is recommended to upgraded to latest commit of the master branch or the latest tag published here.

The installer script has a function to ONLY upgrade ComNetsEmu's dependencies software automatically. And the installer script also needs to be updated firstly. Therefore, it takes three steps to upgrade everything. It is assumed here the ComNetsEmu is installed using option 1 with Vagrant.

Use git to pull (or fetch+merge if you want to) the latest commit in master branch:

$ cd ~/comnetsemu
$ git checkout master
$ git pull origin master

The installer script is used to perform this step. This script ONLY works on supported distributions and has some default variables:

1. The ComNetsEmu's source files are located in "~/comnetsemu"
2. The dependencies installed from source are located in "~/comnetsemu_dependencies"

Run following command to upgrade automatically:

$ cd ~/comnetsemu/util
$ bash ./install.sh -u

The script will ask you to input yes or no several times, please read the terminal output for information.

Run following commands to start basic tests:

$ cd ~/comnetsemu/
$ sudo make test && sudo make test-examples

If all tests pass without any errors or exceptions, the upgrading was successful. Otherwise, it is recommended to redo the upgrade process or rebuild the Vagrant VM if the situation is bad...

$ cd $TOP_DIR/comnetsemu/examples/
$ sudo python3 .dockerindocker.py

See the README to get information about all built-in examples.

To keep the VM size small, the Vagrantfile and test_containers contain only MINIMAL dependencies to bootstrap the VM and able to run all built-in examples. Dependencies of specific applications (e.g. Python packages like numpy, scipy etc.) should be installed by the script or instructions provided in the corresponded application folder. Therefore, the user need to install them only if she or he wants to run that application.

• app: All application programs are classified in this directory. Each subdirectory contains a brief introduction, source codes, Dockerfiles for internal containers and utility scripts of the application.

• comnetsemu: Source codes of ComNetsEmu's Python package.

• examples: Example programs for functionalities of the ComNetsEmu emulator.

• patch: Patches for external dependencies that are installed from source via installer.

• test_containers: Contains Dockerfiles and dependency files for external Docker containers (Docker host).

• utils: Utility and helper scripts.

• Vagrantfile: Vagrant file to setup development/experiment VM environment.

TODO: Add separate development guide

• Run unit tests with coverage report and minimal example tests:

$ sudo make coverage
$ sudo make test-examples

• Run static code checking(with pyflakes, pylint and pep8) and type hints checking (with google/pytype):

$ make codecheck
$ make typecheck

• Remove all created containers and all dangling images. Used to reduce the storage usage.

$ sudo make rm-all-containers
$ sudo make rm-dangling-images

ComNetsEmu's development and API documentation is generated by Sphinx. Dependencies required to build documentation in HTML format are listed here. Please install these dependencies via pip install -r ./doc/requirements.txt. You can install dependencies and build documentation inside the Vagrant VM and view it on your host OS.

Run following commands to build documentation in HTML format and open it with Firefox.

$ make doc
$ firefox ./doc/build/html/index.html

This project exists thanks to all people who contribute. List of all contributors.

Contributing to this repository requires an account of the internal Gitlab server hosted by The Telekom Chair of Communication Networks. Please contact us by Email if you want to have an account.

Project main maintainers:

• Zuo Xiang: zuo.xiang@tu-dresden.de