NodeRED on MilkV Duo S (RISC-V) with Podman and Crun

The RISC-V architecture is naturally interesting and with this project we want to build a container based platform also considering the limited amount of resources that we had on the Milk-V Duo S board.

Thanks to the containerization is simplier to build a final container with docker buildx and use the docker registry to run an application on the board adding packages leveraging the Alpine base image.

In this project we will run NodeRED as main application, just check the folder nodered-app.

Start build container (PC)

docker run -u 1000:1000 -itd --name duodocker \
  -v "$(pwd)":/home/work milkvtech/milkv-duo:latest /bin/bash

And then create the .cache folder

docker exec -it -uroot duodocker mkdir -p /.cache
docker exec -it -uroot duodocker chown -R 1000:1000 /.cache

Enter in the container (PC)

docker exec -it duodocker /bin/bash

the working directory is in the /home/work folder but compiling is in the duo-buildroot-sd-v2

Working in the container

09:02 $ docker exec -it duodocker bash
groups: cannot find name for group ID 1000
I have no name!@9db9201faefe:/$ id
uid=1000 gid=1000 groups=1000
I have no name!@9db9201faefe:/$ 

Create the first build (in the container)

Before cross-compiling podman we have to create the first build

I have no name!@9db9201faefe:/home/work/duo-buildroot-sdk-v2$ ./build.sh milkv-duos-musl-riscv64-sd
Target Top Config: /home/work/duo-buildroot-sdk-v2/build/boards/cv181x/sg2000_milkv_duos_musl_riscv64_sd/sg2000_milkv_duos_musl_riscv64_sd_defconfig
Target Board: milkv-duos-musl-riscv64-sd
Target Board Storage: sd
Target Board Config: /home/work/duo-buildroot-sdk-v2/device/target/boardconfig.sh
Target Board Type: duos
Target Image Config: /home/work/duo-buildroot-sdk-v2/device/target/genimage.cfg
Build tdl-sdk: 1
Output dir: /home/work/duo-buildroot-sdk-v2/install/soc_sg2000_milkv_duos_musl_riscv64_sd

... keep going for the long run

INFO: ext4(rootfs.ext4): cmd: "e2fsck -pvfD '/home/work/duo-buildroot-sdk-v2/install/soc_sg2000_milkv_duos_musl_riscv64_sd/rootfs.ext4'" (stderr):
INFO: hdimage(milkv-duos-musl-riscv64-sd.img): adding primary partition 'boot' (in MBR) from 'boot.vfat' ...
INFO: hdimage(milkv-duos-musl-riscv64-sd.img): adding primary partition 'logo' (in MBR) from 'logo.jpg' ...
INFO: hdimage(milkv-duos-musl-riscv64-sd.img): adding primary partition 'rootfs' (in MBR) from 'rootfs.ext4' ...
INFO: hdimage(milkv-duos-musl-riscv64-sd.img): adding primary partition '[MBR]' ...
INFO: hdimage(milkv-duos-musl-riscv64-sd.img): writing MBR
INFO: cmd: "rm -rf "/home/work/duo-buildroot-sdk-v2/install/soc_sg2000_milkv_duos_musl_riscv64_sd/tmp/"" (stderr):
gnimage for milkv-duos-musl-riscv64-sd success!
/home/work/duo-buildroot-sdk-v2/build
/home/work/duo-buildroot-sdk-v2
Create SD image successful: out/milkv-duos-musl-riscv64-sd_2026-0809-1628.img

This is the first stable build that we can use to test out the board with original sourcecode and also create the riscv64-unknown-linux-musl-gcc compiler that is mandatory to build podman for the RISC-V architecture.

Just flash the sdcard from your PC

PAY ATTENTION ON THOSE COMMANDS THAT DESTROY THE CONTENTS AND PARTITIONS OPF THE DISK SO IDENTIFY THE /dev/sdaX OF THE SDCARD!

sudo umount /dev/sdaX
sudo dd if=out/milkv-duos-musl-riscv64-sd_2026-0809-1628.img of=/dev/sda bs=4M status=progress conv=fsync
sudo eject /dev/sda

Now plug the sdcard in the Milk-V Duo S and check that everything works fine and then move on with the containerized setup.

Working the CRUN and Podman

in order to build podman we need extra packages like libseccomp so we have to select packages and rebuild the project with extra dependencies

Prepare the working dir (in the container)

Override the buildroot configuration

cd /home/work
cp -rp ./buildroot/* duo-buildroot-sdk-v2

Rebuild everything (in the container)

I have no name!@9db9201faefe:/home/work/duo-buildroot-sdk-v2$ ./build.sh milkv-duos-musl-riscv64-sd

This build will take less time than the previous one but it will go for 15 or more minutes and in the final steps of the build you will se the libseccomp and crun infos

...
/home/work/duo-buildroot-sdk-v2/buildroot/utils/brmake -j8 -C /home/work/duo-buildroot-sdk-v2/buildroot
2026-08-09T16:46:15 >>> argp-standalone 1.4.1 Downloading
2026-08-09T16:46:15 >>> host-gperf 3.1 Downloading
2026-08-09T16:46:15 >>> libseccomp 2.5.5 Downloading
2026-08-09T16:46:15 Resolving ftpmirror.gnu.org (ftpmirror.gnu.org)... >>> less 661 Downloading
2026-08-09T16:46:15 >>> vim 9.1.0145 Downloading
2026-08-09T16:46:15 >>> conmon 2.1.8 Downloading
2026-08-09T16:46:15 >>> yajl 2.1.0 Downloading
2026-08-09T16:46:15 >>> crun 1.18.2 Downloading
2026-08-09T16:46:16 >>> nano 8.2 Downloading
2026-08-09T16:46:16 50K .......... ..........>>> argp-standalone 1.4.1 Extracting
2026-08-09T16:46:16 ..... ..Connecting to www.nano-editor.org (www.nano-editor.org)|172.236.11.40|:443... ........>>> libseccomp 2.5.5 Extracting
2026-08-09T16:46:16 ...... ............>>> yajl 2.1.0 Extracting
2026-08-09T16:46:16 150K .......... ........>>> argp-standalone 1.4.1 Patching
2026-08-09T16:46:16 250K ..>>> argp-standalone 1.4.1 Updating config.sub and config.guess
2026-08-09T16:46:17 >>> conmon 2.1.8 Extracting
2026-08-09T16:46:17 ... .......>>> argp-standalone 1.4.1 Configuring
2026-08-09T16:46:17 >>> libseccomp 2.5.5 Patching
2026-08-09T16:46:17 ........ ........>>> libseccomp 2.5.5 Updating config.sub and config.guess
2026-08-09T16:46:17 >>> libseccomp 2.5.5 Patching libtool
2026-08-09T16:46:17 >>> yajl 2.1.0 Patching
2026-08-09T16:46:17 >>> conmon 2.1.8 Patching
2026-08-09T16:46:17 >>> yajl 2.1.0 Configuring
2026-08-09T16:46:17 300K .......... ..>>> less 661 Extracting
2026-08-09T16:46:17 950K ..>>> less 661 Patching
2026-08-09T16:46:17 ........>>> less 661 Updating config.sub and config.guess
2026-08-09T16:46:17 .......... ......>>> less 661 Patching libtool
2026-08-09T16:46:17 >>> argp-standalone 1.4.1 Autoreconfiguring
2026-08-09T16:46:17 >>> less 661 Configuring
2026-08-09T16:46:18 .. .......... ......>>> nano 8.2 Extracting
2026-08-09T16:46:18 ...... .>>> yajl 2.1.0 Building
2026-08-09T16:46:18 900K .......... .......... .......... ...>>> crun 1.18.2 Extracting
2026-08-09T16:46:18 >>> nano 8.2 Patching
2026-08-09T16:46:18 >>> crun 1.18.2 Patching
2026-08-09T16:46:18 >>> nano 8.2 Updating config.sub and config.guess
2026-08-09T16:46:18 1450K .......... .......... .......... .......... ......>>> nano 8.2 Patching libtool
2026-08-09T16:46:18 >>> crun 1.18.2 Updating config.sub and config.guess
2026-08-09T16:46:19 1700K .......... .......... .......... ..>>> nano 8.2 Configuring
2026-08-09T16:46:19 3750K .......... ..........>>> yajl 2.1.0 Installing to staging directory
2026-08-09T16:46:19 .. .......... ..>>> yajl 2.1.0 Fixing libtool files
2026-08-09T16:46:19 4100K .......... .......... .........>>> yajl 2.1.0 Installing to target
2026-08-09T16:46:21 8050K .......... .......... ....>>> argp-standalone 1.4.1 Patching libtool
2026-08-09T16:46:22 checking for malloc.h... checking whether the compiler supports GNU C... (cached) >>> vim 9.1.0145 Extracting
2026-08-09T16:46:23 checking for fsync... >>> vim 9.1.0145 Patching
2026-08-09T16:46:23 checking for mbsinit... >>> vim 9.1.0145 Updating config.sub and config.guess
2026-08-09T16:46:23 checking for strndup... >>> vim 9.1.0145 Patching libtool
2026-08-09T16:46:23 checking for nanosleep... >>> vim 9.1.0145 Configuring
2026-08-09T16:46:25 checking for usleep... >>> argp-standalone 1.4.1 Building
2026-08-09T16:46:26 >>> argp-standalone 1.4.1 Installing to staging directory
2026-08-09T16:46:26 >>> argp-standalone 1.4.1 Fixing libtool files
2026-08-09T16:46:26 >>> argp-standalone 1.4.1 Installing to target
2026-08-09T16:46:26 checking for vasnprintf... >>> host-gperf 3.1 Extracting
2026-08-09T16:46:27 >>> host-gperf 3.1 Patching
2026-08-09T16:46:27 >>> host-gperf 3.1 Updating config.sub and config.guess
2026-08-09T16:46:27 >>> host-gperf 3.1 Patching libtool
2026-08-09T16:46:27 checking for wcwidth... >>> host-gperf 3.1 Configuring
2026-08-09T16:46:27 >>> less 661 Building
2026-08-09T16:46:29 checking whether we are using the GNU C compiler... >>> less 661 Installing to target
2026-08-09T16:46:31 >>> host-gperf 3.1 Building
2026-08-09T16:46:32 >>> host-gperf 3.1 Installing to host directory
2026-08-09T16:46:32 checking whether long double and double are the same... >>> libseccomp 2.5.5 Configuring
2026-08-09T16:46:36 checking for struct sched_param... >>> libseccomp 2.5.5 Building
2026-08-09T16:46:38 >>> libseccomp 2.5.5 Installing to staging directory
2026-08-09T16:46:38 >>> libseccomp 2.5.5 Fixing libtool files
2026-08-09T16:46:38 checking for vsnprintf... >>> libseccomp 2.5.5 Installing to target
2026-08-09T16:46:38 >>> conmon 2.1.8 Configuring
2026-08-09T16:46:38 >>> crun 1.18.2 Configuring
2026-08-09T16:46:40 checking whether float.h conforms to ISO C23... >>> crun 1.18.2 Autoreconfiguring
2026-08-09T16:46:40 checking for sysconf... >>> conmon 2.1.8 Building
2026-08-09T16:46:42 checking whether isnan(float) can be used without linking with libm... >>> conmon 2.1.8 Installing to target
2026-08-09T16:46:43 checking for PTHREAD_MUTEX_ROBUST... >>> vim 9.1.0145 Building
2026-08-09T16:46:55 >>> nano 8.2 Building
2026-08-09T16:47:08 >>> crun 1.18.2 Patching libtool
2026-08-09T16:47:17 checking for criu >= 3.15... >>> nano 8.2 Installing to target
2026-08-09T16:47:18 >>> vim 9.1.0145 Installing to target
2026-08-09T16:47:25 >>> crun 1.18.2 Building
2026-08-09T16:47:40 >>> crun 1.18.2 Installing to target
2026-08-09T16:47:40 >>>   Finalizing host directory
2026-08-09T16:47:47 >>>   Finalizing target directory
2026-08-09T16:47:51 >>>   Sanitizing RPATH in target tree
2026-08-09T16:47:52 >>>   Copying overlay board/milkv/milkv-duos-musl-riscv64-sd/overlay
2026-08-09T16:47:53 >>>   Copying overlay /home/work/br2-containers/overlay
2026-08-09T16:47:53 >>>   Generating root filesystems common tables
2026-08-09T16:47:53 >>>   Generating filesystem image rootfs.ext2
2026-08-09T16:47:53 >>>   Generating filesystem image rootfs.tar
...

Now we can move on with the build of the podman executable

download Golang

sh scripts/download-go.sh

Build podman executable (in the container)

I have no name!@9db9201faefe:/$ cd /home/work/
I have no name!@9db9201faefe:/home/work$ bash scripts/podman-env.sh 

The build process should end with

podman: ELF 64-bit LSB executable, UCB RISC-V, RVC, double-float ABI, version 1 (SYSV), dynamically linked, interpreter /lib/ld-musl-riscv64.so.1, BuildID[sha1]=59c7ff852ffa4d4395b32a4dde8600f2f8d391a9, stripped

but we can check that the podman executable is there

I have no name!@9db9201faefe:/home/work$ ls -las podman-src/podman
41072 -rwxr-xr-x 1 1000 1000 42056424 Aug  9 16:53 podman-src/podman
I have no name!@9db9201faefe:/home/work$ file podman-src/podman
podman-src/podman: ELF 64-bit LSB executable, UCB RISC-V, RVC, double-float ABI, version 1 (SYSV), dynamically linked, interpreter /lib/ld-musl-riscv64.so.1, BuildID[sha1]=59c7ff852ffa4d4395b32a4dde8600f2f8d391a9, stripped

Prepare the final complete build (in the container)

Now with the script board-env.sh we will prepare the final filesystem and we will copy the binary from podman in the right folder on the target.

I have no name!@9db9201faefe:/$ cd /home/work/
I have no name!@9db9201faefe:/home/work$ bash scripts/board-env.sh 
cp: cannot stat 'containers-backup/*': No such file or directory
/home/work/br2-containers/overlay/etc/containers/containers.conf
/home/work/br2-containers/overlay/etc/containers/policy.json
/home/work/br2-containers/overlay/etc/containers/storage.conf
/home/work/br2-containers/overlay/etc/containers/registries.conf
/home/work/br2-containers/overlay/etc/init.d/S40containers
/home/work/br2-containers/overlay/usr/local/bin/.gitentry
/home/work/br2-containers/overlay/usr/local/bin/podman

Rebuild the final image (in the container)

If you want you can skip a final rebuild and create the folder's structure that you find in the br2-containers and coping the binary from podman in the /usr/bin folder in the target.

Otherwise just build the final image with all dependencies and finally create your latest sdcard and test everything out directly in a simplier way.

I have no name!@9db9201faefe:/$ cd /home/work/duo-buildroot-sdk-v2/
I have no name!@9db9201faefe:/home/work/duo-buildroot-sdk-v2$ ./build.sh milkv-duos-musl-riscv64-sd

The command will keep running for several minutes again but at the end you will have a target image with containerization working.

Test out a simple Alpine container (on the milk-v board)

Just spin up a container

podman run --rm --network=host docker.io/riscv64/alpine echo ok

Start NodeRED (on the milk-v board)

Just start it up

podman run -d --network=host wdalmut/nodered

The process will take a minute to startup so check the container's logs and then with your browser go directly on http://192.168.42.1:1880.

Build your own images and copying in the Milk-v (on the host)

If you want to build your own containers and copying directly on the board without passing through the register you can build RISC-V images.

Only the first time start the buildx toolchain

docker run --privileged --rm tonistiigi/binfmt --install riscv64
docker buildx create --name rvbuilder --use   # driver docker-container

then just build your images leveraging your own Dockerfile

docker buildx build --platform linux/riscv64 \
  -t nodered-rv:1.0 \
  --output type=oci,dest=nodered-rv.tar .

Now you can copy the tar file on the Milk-V board (or push previusly to the Docker register)

scp -O nodered-rv.tar root@192.168.42.2:/mnt/sd/

Then on the Milk-V

podman load -i /mnt/sd/nodered-rv.tar

Then check your images

podman images

You should see your brand new image and then you can use it!

podman run -it --rm  <your-image-name> 

Adding extra packages (in the container)

cd buildroot/output/milkv-duos-musl-riscv64-sd/
make menuconfig          # '/' per cercare (es. "package_vim")
make savedefconfig       # scrive nel defconfig sorgente