install_gz11_side_by_side.md

Installing Gazebo11 side by side with new Gazebo

Supported Gazebo versions and Ubuntu platforms for this tutorial

This tutorial affects the Gazebo Classic users on Ubuntu Jammy (latest Ubuntu release were Gazebo Classic packages supported by the Gazebo team) that plan on migrating code to new Gazebo Fortress, Garden or Harmonic.

There is no guarantee that the Gazebo Classic version detailed in this document will be updated in any case. Please consider the migration to the new Gazebo as the recommended alternative.

General context and migrations to new Gazebo

New versions of Gazebo can not be installed together with Gazebo Classic (aka gazebo11) since both use the gz command line tool. Trying to install gz-garden or gz-harmonic from packages.osrfoundation.org on a system that already has gazebo-classic installed from binaries will cause gazebo-classic and its dependencies to be uninstalled.

Having a side by side installation of both can make easier the recommended migration to newer versions of Gazebo.

Alternative approach for Gazebo Classic without the gz tool

A possible workaround could be to use Gazebo Classic without the gz command or with a renamed gz command. This can be particularly interesting since the ROS (Robot Operative System) wrapper known as gazebo_ros_pkgs do not use the gz command but the gzserver and gzclient commands.

Not shipping the gz command by default in a Gazebo Classic installation would be a disruptive change for existing users so it should not be hosted in packages.osrfoundation.org.

Gazebo11 with a separate gz tool package

This alterntive approach has been implemented and packages for jammy are hosted in the Open Robotics gazebo11-gz-cli PPA: https://launchpad.net/~openrobotics/+archive/ubuntu/gazebo11-gz-cli

The PPA contains a gazebo11 version that ships the gz executable in an independent packages called gazebo11-gz-cli while the main gazebo11 package has a gz11 command. Both are really symlinks to gz-11.x.y.

How the packaging works for the gz command

The gazebo11-gz-cli is a soft dependency on gazebo11. It is installed by default but it will be uninstalled when installing the new Gazebo packages and the effect is that the gz command for Gazebo Classic replaced by the gz tool from new Gazebo. The gz11 command can be used instead of the gz command to access to the same functionality.

Installing the new packaging from the PPA

From an existing gazebo11 installation (on jammy the Ubuntu official repositories will install 11.10.2+dfsg-1 version) or a non existing gazebo11 installation the steps are the following:

sudo add-apt-repository ppa:openrobotics/gazebo11-gz-cli
sudo apt update
sudo apt-get install gazebo11

If gazebo11 was installed before, it will be upgraded to the version in the PPA. From this point, a new Gazebo installation for fortress, garden or harmonic can be executed.

If a new Gazebo installation was installed before, the gazebo11-gz-cli package won't be installed.