根据官方的文档在ubunt20.04上安装ROS2后 导入环境可能会出现下面的警告：

解决方法如下：

安装RTI Connext

导入设置文件设置 NDDSHOME 环境变量

附官方文档

Ubuntu Linux source install

RTI Connext (version 5.3.1, amd64 only)

Debian packages provided in the ROS 2 apt repositories

You can install a Debian package of RTI Connext available on the ROS 2 apt repositories. You will need to accept a license from RTI.

 sudo apt install -q -y \
     rti-connext-dds-5.3.1  # from packages.ros.org/ros2/ubuntu

Source the setup file to set the NDDSHOME environment variable.

 cd /opt/rti.com/rti_connext_dds-5.3.1/resource/scripts && source ./rtisetenv_x64Linux3gcc5.4.0.bash; cd -

Note: when using zsh you need to be in the directory of the script when sourcing it to have it work properly

Now you can build as normal and support for RTI will be built as well.

Official binary packages from RTI

You can install the Connext 5.3.1 package for Linux provided by RTI, via options available for university, purchase or evaluation

After downloading, use chmod +x on the .run executable and then execute it. Note that if you’re installing to a system directory use sudo as well.

The default location is ~/rti_connext_dds-5.3.1

After installation, run RTI launcher and point it to your license file (obtained from RTI).

Add the following line to your .bashrc file pointing to your copy of the license.

 export RTI_LICENSE_FILE=path/to/rti_license.dat

Source the setup file to set the NDDSHOME environment variable.

 source ~/rti_connext_dds-5.3.1/resource/scripts/rtisetenv_x64Linux3gcc5.4.0.bash

Now you can build as normal and support for RTI will be built as well.

Ubuntu Linux binary install

RTI Connext (version 5.3.1, amd64 only)

To use RTI Connext DDS there are full-suite install options available for university, purchase or evaluation or you can install a libraries-only Debian package of RTI Connext 5.3.1, available from the OSRF Apt repository under a non-commercial license.

To install the libs-only Debian package:

 sudo apt update && sudo apt install -q -y rti-connext-dds-5.3.1

You will need to accept a license agreement from RTI, and will find an ‘rti_license.dat file in the installation.

Add the following line to your .bashrc file pointing to your copy of the license (and source it).

 export RTI_LICENSE_FILE=path/to/rti_license.dat

All options need you to source the setup file to set the NDDSHOME environment variable:

 cd /opt/rti.com/rti_connext_dds-5.3.1/resource/scripts && source ./rtisetenv_x64Linux3gcc5.4.0.bash; cd -

Note: the above may need modification to match your RTI installation location

If you want to install the Connext DDS-Security plugins please refer to this page.

OSX source install

RTI Connext (5.3)

If you would like to also build against RTI Connext DDS there are options available for university, purchase or evaluation

You also need a Java runtime installed to run the RTI code generator, which you can get here.

After installing, run RTI launcher and point it to your license file.

Source the setup file to set the NDDSHOME environment variable before building your workspace.

The setup file and path will depend on your macOS version.

 # macOS 10.12 Sierra
 source /Applications/rti_connext_dds-5.3.1/resource/scripts/rtisetenv_x64Darwin16clang8.0.bash
 # macOS 10.13 High Sierra
 source /Applications/rti_connext_dds-5.3.1/resource/scripts/rtisetenv_x64Darwin17clang9.0.bash

You may need to increase shared memory resources following https://community.rti.com/kb/osx510

If you want to install the Connext DDS-Security plugins please refer to this page.

OSX binary install

Enable Connext support

To use RTI Connext DDS there are options available for university, purchase or evaluation

After installing, run RTI launcher and point it to your license file.

Set the NDDSHOME environment variable:

 export NDDSHOME=/Applications/rti_connext_dds-5.3.1

You may need to increase shared memory resources following https://community.rti.com/kb/osx510.

If you want to install the Connext DDS-Security plugins please refer to this page.

Windows source install

RTI Connext 5.3

If you would like to also build against RTI Connext DDS there are options available for university, purchase or evaluation

After installing, use the RTI Launcher to load your license file.

Then before building ROS 2, set up the Connext environment:

 call "C:\Program Files\rti_connext_dds-5.3.1\resource\scripts\rtisetenv_x64Win64VS2017.bat"

Note that this path might need to be slightly altered depending on where you selected to install RTI Connext DDS, and which version of Visual Studio was selected. The path above is the current default path as of version 5.3.1, but will change as the version numbers increment in the future.

If you want to install the Connext DDS-Security plugins please refer to this page.

Windows binary install

RTI Connext

To use RTI Connext DDS there are options available for university, purchase or evaluation

After installing, run RTI launcher and point it to your license file.

Set the NDDSHOME environment variable:

 set "NDDSHOME=C:\Program Files\rti_connext_dds-5.3.1"

If you want to install the Connext DDS-Security plugins please refer to this page.