NI Linux Real-Time

Introduction

This project builds packages and images for the NI Linux RT distribution.

NI Linux RT is a Real-Time-scheduling enabled OS, for use on NI's embedded hardware devices. This project uses the OpenEmbedded framework to build and package the kernel, software, images, and installation media which compose NI Linux RT.

Community (non-NI) developers can use this project to build packages for open-source software projects, which are installable to their existing NI Linux RT devices - including custom Linux kernels and kernel modules.

Additional community documentation can be found at https://nilrt-docs.ni.com.

Mainlines

This project currently has three concurrent development mainlines (sorry). They are, in short:

• nilrt/master/kirkstone - the current x64 dev HEAD
• nilrt/master/sumo - the current arm32 dev HEAD
• nilrt-academic/master/sumo - a forked arm32 HEAD for FIRST Robotics Competition

Entering the Bitbake Build Environment

This project uses the pyrex tool to transparently provide most of the toolchain requirements needed to run bitbake. However, there are are still a few setup steps.

1. Initial repo and submodules

   Checkout the source and initialize the project submodules.

   git clone https://github.com/ni/nilrt.git
   cd nilrt
   git checkout nilrt/$release
   git submodule init
   git submodule update --remote --checkout

2. Install docker

   Install the docker engine on your build host. If you can successfully run docker run hello-world, then you have everything you should need.

   Do not use the Docker Desktop product as your docker installation. Docker Desktop uses virtual machine indirection that will interfere with this project's docker scripting. Other users have had success switching to the bare docker engine instead.

3. Set up pyrex

   Build (or pull) the build-nilrt pyrex container image.

   bash ./docker/create-build-nilrt.sh  # will tag the image as build-nilrt:${NILRT_codename}
   
   # Verification
   docker images build-nilrt  # should print the image you just built

4. Set up build environment

   Source the ni-oe-init-build-env script, using the . (or source) command in your shell. This will automatically setup your OpenEmbedded build environment, and the pyrex container shim that will transparently wrap your bitbake commands.

   . ./ni-oe-init-build-env [--org]
   
   # Verification
   bitbake --version  # If this succeeds, you're done.

   If you are building on a virtual machine and do not have nested virtualization enabled on the host, you will need to locally remove the --device /dev/kvm entry in the args assignment in the top-level pyrex.ini file.

   If you are building on a host with an older version of libseccomp, you may need to add --security-opt seccomp=unconfined entry in the args assignment in the top-level pyrex.ini file to work around build errors, as described here.

   NI builders who are connected to the NI corporate network should specify -org in their init script args, to provoke the script into adding the ni-org.conf snippet to your bitbake directory. External builders should not use --org.

   If you are building on a nilrt/master/* branch ref (rather than a release branch) and if you are building outside of the NI corporate network, you will need to set the version of the ni-main opkg feed to one which has already been published to download.ni.com. Do this by setting the NILRT_MAIN_FEED_VERSION bitbake variable to the latest published release. eg.

   echo 'NILRT_MAIN_FEED_VERSION = "2022Q3"' >> ./conf/local.conf
   

5. Build package or packagegroups

   For example, to build Python, Ruby, and Apache for x64 targets, run the following commands:

    bitbake python3 ruby apache2
   

   To build all supported OpenEmbedded packages in NI's feed, run the following commands to build these packagegroups:

    bitbake packagefeed-ni-core
   

   NOTE. If a package within a package group is updated, rebuilding the package group will automatically rebuild that package and all of its dependencies.

   NOTE. The configuration files (build/conf/*.conf) can optionally be changed to reflect the desired build settings instead of setting environment variables.

   NOTE. Building packages through OpenEmbedded can use significant disk space, on the order of 100s of gigabytes. If you are preparing a virtual machine to build images, make sure to allocate sufficient disk space.

   The resulting ipk files that can be installed through opkg exist at the following directory:

    tmp-glibc/deploy/ipk/...
   

6. Building package feeds

   The NILRT repo has scripting in the :scripts/pipelines/ directory, which can be used to automate the process of building package feeds. The NI build pipelines use these scripts directly - so they are canonical.

   # after completing the build setup steps above...
   bash ../scripts/pipelines/build.core-feeds.sh

   These scripts are also a good source for understanding the steps to build a package feed manually. Note that if you are building package feeds manually, you must bitbake the special package-index target before using the feed.

7. Building various images

   NOTE You must build packagefeed-ni-core and package-index first to build images.

   • Build a safemode image by running the following command:

       bitbake nilrt-safemode-rootfs
     

     The resulting root file system images for the NILRT safemode image is located at the following paths:

       tmp-glibc/deploy/images/x64/nilrt-safemode-rootfs-x64.tar.gz
     

     You can install this on target by copying the file over to the target and running the following command:

       tar xf nilrt-safemode-rootfs-x64.tar.gz -C /boot/.safe/
     

   • Build a runmode image by running the following command:

       bitbake nilrt-base-system-image
     

     The resulting root file system images for the NILRT runmode image is located at the following paths:

       tmp-glibc/deploy/images/x64/nilrt-base-system-image-x64.tar
     

     You can install this on target by copying the file over to the target while the target is in safe mode and running the following commands:

       tar xf nilrt-base-system-image-x64.tar
       tar xf data.tar.gz -C /mnt/userfs && ./postinst
     

   • Build a bootable recovery media by running the following command:

       bitbake nilrt-recovery-media
     

     The bootable recovery media, which you can install onto a USB memory stick or burn to a CD, is located at the following path:

       tmp-glibc/deploy/images/x64/nilrt-recovery-media-x64.iso
     

     Boot your NI Linux Real-Time compatible hardware from the recovery media and follow on-screen instructions to perform a factory reset.

   NOTE By default, National Instruments software is pulled from a feed hosted on ni.com. You can redirect to a mirror by setting IPK_NI_SUBFEED_URI to any URI supported by opkg in your org.conf,site.conf, or auto.conf.

8. Building the cross-compile toolchain

   In order to compile custom packages for NI Linux Real-Time on a host system, a cross-compile toolchain is necessary. This can be built directly from one of the scripts in the :scripts/pipelines/ directory. By default, it builds for x86_64 Linux hosts.

   bash ../scripts/pipelines/build.toolchain.sh

   During the build, a script is generated at $BUILDDIR/tmp-glibc/deploy/sdk, with a name like oecore-x86_64-core2-64-toolchain-9.2.sh. The script is a self-extracting archive, and can be copied to and executed on an appropriate host system to install the toolchain.

   To build the toolchain for an x86_64 Windows host, there is a different script that can be used.

   bash ../scripts/pipelines/build.cross-toolchain.sh

   During the build, an archive is generated at $BUILDDIR/tmp-glibc/deploy/sdk, with a name like oecore-x86_64-core2-64-toolchain.tar.xz. This archive can be extracted on a Windows system to to access the toolchain.

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Enjoy, and happy hacking!
ni.com/community/