Installing ROS Melodic & ROS Dashing inside a Ubuntu Bionic chroot

• Install Ubuntu inside a chroot. Follow guide from here
• Fix /etc/resolv.conf

nameserver 8.8.8.8

• Fix /etc/hosts. On the second line put the name of your hostname instead of 'shirka'.

127.0.0.1	localhost
127.0.1.1	shirka

• Add all ubuntu repositories. Edit file /etc/apt/sources.list:

deb http://mirrors.ucr.ac.cr/ubuntu bionic main universe restricted multiverse
deb http://mirrors.ucr.ac.cr/ubuntu bionic-updates main universe restricted multiverse
deb http://mirrors.ucr.ac.cr/ubuntu bionic-backports main restricted multiverse

• Update repos

$ apt-get update

• Install the following packages:

$ apt-get install sudo mc nano curl lsb-release gnupg2 apt-utils bash-completion locales

• Add a new user in the chroot

$ adduser user

• Add your new user to sudo group

$ adduser user sudo

• Fix sudo error with visudo:

$ visudo

%sudo   ALL=(ALL:ALL) NOPASSWD:ALL

• From now on, use your new user for the following steps:

$ su user

• Follow guide for ROS Melodic from ROS: http://wiki.ros.org/melodic/Installation/Ubuntu
• Follow guide for ROS Dashing from ROS: https://index.ros.org/doc/ros2/Installation/Dashing/Linux-Install-Debians/

Since ROS Hydro (ROS 1), ROS use Catkin for building all packages. The following links shows the basic steps for creating a Catkin Workspace.

• Create a workspace

After creating the workspace, build a basic package for testing purposes.

• Create a ROS package
• Writing a simple node in Python
• Running the simple node

Since ROS Crystal (ROS 2) to newer versions, ROS use Colcon for building all packages. This guide shows the basic steps for creating a Colcon Workspace.

• Source ROS 2 configuration

$ source /opt/ros/dashing/setup.bash

• Install colcon

$ sudo apt install python3-colcon-common-extensions

• Create workspace for ROS 2

$ mkdir -p ~/ros2_ws/src

• Move to the new workspace and build it

$ cd ~/ros2_ws
$ colcon build

• Source workspace configuration

$ source ~/ros2_ws/install/local_setup.bash && source ~/ros2_ws/install/setup.bash

After creating the workspace, lets build some examples packages for ROS 2.

• Clone ROS 2 examples package repository in our workspace

$ cd ~/ros2_ws/src
$ git clone git clone https://github.com/ros2/examples
$ git checkout $ROS_DISTRO

• Build examples package

$ cd ~/ros2_ws
$ colcon build --symlink-install

• Test builded package. Remember to run each command on different terminals and source ROS 2 configuration on each terminal.

$ ros2 run examples_rclcpp_minimal_subscriber subscriber_member_function
$ ros2 run examples_rclcpp_minimal_publisher publisher_member_function