You're reading the documentation for a version of ROS 2 that has reached its EOL (end-of-life), and is no longer officially supported. If you want up-to-date information, please have a look at Iron.

Building ROS 2 on Linux

System requirements

Target platforms for Crystal Clemmys are (see REP 2000):

  • Tier 1: Ubuntu Linux - Bionic Beaver (18.04) 64-bit

  • Tier 2: Ubuntu Linux - Xenial Xerus (16.04) 64-bit

Tier 3 platforms (not actively tested or supported) include:

System setup

Set locale

Make sure to set a locale that supports UTF-8. If you are in a minimal environment such as a Docker container, the locale may be set to something minimal like POSIX.

The following is an example for setting locale. However, it should be fine if you’re using a different UTF-8 supported locale.

sudo locale-gen en_US en_US.UTF-8
sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
export LANG=en_US.UTF-8

Add the ROS 2 apt repository

You will need to add the ROS 2 apt repositories to your system. To do so, first authorize our GPG key with apt like this:

sudo apt update && sudo apt install curl gnupg2 lsb-release
curl -s | sudo apt-key add -

And then add the repository to your sources list:

sudo sh -c 'echo "deb [arch=$(dpkg --print-architecture)] $(lsb_release -cs) main" > /etc/apt/sources.list.d/ros2-latest.list'

Install development tools and ROS tools

sudo apt update && sudo apt install -y \
  build-essential \
  cmake \
  git \
  python3-colcon-common-extensions \
  python3-lark-parser \
  python3-pip \
  python-rosdep \
  python3-vcstool \
# install some pip packages needed for testing
python3 -m pip install -U \
  argcomplete \
  flake8 \
  flake8-blind-except \
  flake8-builtins \
  flake8-class-newline \
  flake8-comprehensions \
  flake8-deprecated \
  flake8-docstrings \
  flake8-import-order \
  flake8-quotes \
  pytest-repeat \
  pytest-rerunfailures \
  pytest \
  pytest-cov \
  pytest-runner \
# install Fast-RTPS dependencies
sudo apt install --no-install-recommends -y \
  libasio-dev \

Get ROS 2 code

Create a workspace and clone all repos:

mkdir -p ~/ros2_crystal/src
cd ~/ros2_crystal
vcs import src < ros2.repos

Install dependencies using rosdep

sudo rosdep init
rosdep update
# [Ubuntu 18.04]
rosdep install --from-paths src --ignore-src --rosdistro crystal -y --skip-keys "console_bridge fastcdr fastrtps libopensplice67 libopensplice69 rti-connext-dds-5.3.1 urdfdom_headers"
# [Ubuntu 16.04]
rosdep install --from-paths src --ignore-src --rosdistro crystal -y --skip-keys "console_bridge fastcdr fastrtps libopensplice67 libopensplice69 python3-lark-parser rti-connext-dds-5.3.1 urdfdom_headers"
python3 -m pip install -U lark-parser

Install additional DDS implementations (optional)

If you would like to use another DDS or RTPS vendor besides the default, eProsima’s Fast RTPS, you can find instructions here.

Build the code in the workspace

Note: to build the ROS 1 bridge, read the ros1_bridge instructions.

More info on working with a ROS workspace can be found in this tutorial.

cd ~/ros2_crystal/
# On Ubuntu Linux Bionic Beaver 18.04
colcon build --symlink-install
# On Ubuntu Linux Xenial Xerus 16.04
colcon build --symlink-install --packages-ignore qt_gui_cpp rqt_gui_cpp

Note: if you are having trouble compiling all examples and this is preventing you from completing a successful build, you can use AMENT_IGNORE in the same manner as CATKIN_IGNORE to ignore the subtree or remove the folder from the workspace. Take for instance: you would like to avoid installing the large OpenCV library. Well then simply $ touch AMENT_IGNORE in the cam2image demo directory to leave it out of the build process.

Optionally install all packages into a combined directory (rather than each package in a separate subdirectory). On Windows due to limitations of the length of environment variables you should use this option when building workspaces with many (~ >> 100 packages).

Also, if you have already installed ROS 2 from Debian make sure that you run the build command in a fresh environment. You may want to make sure that you do not have source /opt/ros/${ROS_DISTRO}/setup.bash in your .bashrc.

colcon build --symlink-install --merge-install

Afterwards source the local_setup.* from the install folder.

Environment setup

Source the setup script

Set up your environment by sourcing the following file.

. ~/ros2_crystal/install/setup.bash

Install argcomplete (optional)

ROS 2 command line tools use argcomplete to autocompletion.

So if you want autocompletion, installing argcomplete is necessary.

sudo apt install python3-argcomplete

Try some examples

In one terminal, source the setup file and then run a C++ talker:

. ~/ros2_crystal/install/local_setup.bash
ros2 run demo_nodes_cpp talker

In another terminal source the setup file and then run a Python listener:

. ~/ros2_crystal/install/local_setup.bash
ros2 run demo_nodes_py listener

You should see the talker saying that it’s Publishing messages and the listener saying I heard those messages. This verifies both the C++ and Python APIs are working properly. Hooray!

See the tutorials and demos for other things to try.

Alternate compilers

Using a different compiler besides gcc to compile ROS 2 is easy. If you set the environment variables CC and CXX to executables for a working C and C++ compiler, respectively, and retrigger CMake configuration (by using --force-cmake-config or by deleting the packages you want to be affected), CMake will reconfigure and use the different compiler.


To configure CMake to detect and use Clang:

sudo apt install clang
export CC=clang
export CXX=clang++
colcon build --cmake-force-configure

TODO: using ThreadSanitizer, MemorySanitizer

Stay up to date

See Maintaining a source checkout of ROS 2 to periodically refresh your source installation.


Troubleshooting techniques can be found here.


  1. If you installed your workspace with colcon as instructed above, “uninstalling” could be just a matter of opening a new terminal and not sourcing the workspace’s setup file. This way, your environment will behave as though there is no Crystal install on your system.

  2. If you’re also trying to free up space, you can delete the entire workspace directory with:

    rm -rf ~/ros2_crystal