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Nest Labs Happy -- a network topology orchestration tool


Happy simulates complex network topologies. On a single Linux machine, Happy can create multiple nodes with network stacks that are independent from each other. Some nodes may be connected to simulated Thread networks, others may connect to simulated Wi-Fi, WAN (Internet), or cellular networks.

Happy addresses the following use cases:

  • Testing of network protocols and other distributed execution programs on a single Linux development machine without using hardware.
  • Performing automated functional testing across a network.
  • Running multiple concurrent, parallel networks on the same system to improve testing throughput.

Happy solves these problems by creating network topology abstractions with minimal user overhead. Complex topologies may be created with a single shell command call. Happy supports both interactive use and automated scripting.

Use Happy shell commands to set up, test, and debug their code during development. The same networking configuration and test programs may then be scripted and used in automated testing.

Getting Started

The quickest and easiest way to get started with Happy is to go through our Getting Started with Happy and Weave Codelab. It walks the user through all the Happy fundamentals, including:

  • Creating and deleting a topology
  • Networking nodes together
  • Saving and restoring topologies
  • Connecting a topology to the internet
  • Weave fundamentals


Happy has a strong dependence on Linux Network Namespaces, and as a result, is only supported in the Linux environment.


# Mandatory: python-setuptools
sudo apt-get install python-setuptools
# Mandatory: Linux bridge utilities
sudo apt-get install bridge-utils
# Mandatory: python-lockfile
sudo apt-get install python-lockfile
# Mandatory: python-psutil
sudo apt-get install python-psutil
# Optional: Graphic Tools
sudo apt-get install python-networkx
sudo apt-get install python-matplotlib
# Optional: Tmux
sudo apt-get install tmux


Before using Happy, it must be installed. Running Happy from the source tree is not supported. To install, run:


This does two things:

  • Creates a happy python package at /usr/local/lib/python2.7/dist-packages
  • Copies happy shell scripts to /usr/local/bin

After installation, Happy Python packages can be imported into Python environment as any other Python module (e.g. import happy). Post installation, all system users can make Happy shell calls. (e.g. $ happy-state).

Verify installation

At this point Happy commands should be visible from the shell. Calling happy-state should return the following:

$ happy-state

NETWORKS   Name         Type   State                                     Prefixes

NODES      Name    Interface    Type                                          IPs

Removing Happy

Before removing Happy make sure that all virtual nodes and networks are deleted. The simplest way of wiping out past Happy work is by calling happy-state-delete -a:

happy-state-delete -a

To remove Happy itself, call make uninstall within the Happy repo and remove happy/bin from the host's $PATH:

make uninstall
# Delete happy files from ~ (user home directory)
rm -f ~/.happy_state.json
rm -f ~/.happy_conf.json
rm -f ~/.happy_state.json.lock
cd /usr/local/lib/python2.7/dist-package
rm -f happy*

Happy commands

Most Happy commands follow the same basic syntax. Common flags are:

Flag Description
-h --help Show help information for the command
-q --quiet Turn off command output
-a --add Create/add; the default action for a command is -a unless otherwise specified
-d --delete Delete; this action must be specified to perform a delete action

For all commands, the short and long flags are interchangeable, and in some instances can be omitted entirely. For example, all three of these commands are equivalent:

$ happy-node-join ThreadNode ThreadNetwork
$ happy-node-join -i ThreadNode -n ThreadNetwork
$ happy-node-join --id ThreadNode --network ThreadNetwork

If neither -a nor -d is used, -a is assumed. For example, these two commands are equivalent:

$ happy-dns onhub
$ happy-dns -a onhub

Usage of sudo

Happy changes the network configuration that is controlled by the Linux kernel. Since only root can change the kernel configuration, Happy prompts you to enter the sudo password during operation.

Happy uses the $SUDO system environment variable to call sudo. If $SUDO is not defined, Happy makes a normal sudo call. The user can change the sudo command value through $SUDO.


Comprehensive end-user documentation, including Setup and Usage guides, are located at

An architectural overview of Happy can be found in Significant contributions or alterations to the Happy functionality must be accompanied by documentation within this repository, or submitted as an Issue for incorporation on

Want to contribute?

Contributions are welcome and encouraged. See for details.


Happy is a tool for lightweight orchestration of simulated network topologies used for development and testing of IOT home area networks







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