Using MediaMTX with Balena on an RPI

[Efrank700]

Question

I'm currently working on getting MediaMTX running on a balena image for WebRTC streaming of video. I'm on a Raspberry Pi Zero 2 W with a Camera Module 3.

I'm running into a wall of messages from the executable. Once I start it, I see
[RPI Camera source] fork/exec /dev/shm/mediamtx-rpicamera-1745026858688842897/mtxrpicam: permission denied

This message has occurred consistently whether i have built from source or used the binary. I've ensured that my service has

tmpfs:
      - /dev/shm:exec

but I still run into this issue.

What's the right place to start looking to debug this further? I ran with debug but wasn't able to see any further useful logs.

Docker Compose:

  libcamera:
    build: ./
    restart: always
    privileged: true
    ports:
      - "5000:5000"
    tmpfs:
      - /dev/shm:exec
    environment:
      - DBUS_SYSTEM_BUS_ADDRESS=unix:path=/host/run/dbus/system_bus_socket
    labels:
      io.balena.features.dbus: '1' # required for stopping host OS bluetooth.service
      io.balena.features.kernel-modules: '1'

Version: 1.12.0 for Linux ARM64

Full logs below:

root@632fe8f9b55a:/# ./mediamtx mediamtx.yml 
2025/04/19 01:43:49 INF MediaMTX v1.12.0
2025/04/19 01:43:49 INF configuration loaded from /mediamtx.yml
2025/04/19 01:43:49 DEB [path cam] created
2025/04/19 01:43:49 DEB path manager created
2025/04/19 01:43:49 INF [path cam] [RPI Camera source] started
2025/04/19 01:43:49 INF [RTSP] listener opened on :8554 (TCP), :8000 (UDP/RTP), :8001 (UDP/RTCP)
2025/04/19 01:43:49 INF [RTMP] listener opened on :1935
2025/04/19 01:43:49 INF [HLS] listener opened on :8888
2025/04/19 01:43:49 INF [WebRTC] listener opened on :5000 (HTTP), :8189 (ICE/UDP)
2025/04/19 01:43:49 INF [SRT] listener opened on :8890 (UDP)
2025/04/19 01:43:49 ERR [path cam] [RPI Camera source] fork/exec /dev/shm/mediamtx-rpicamera-1745027029377906600/mtxrpicam: permission denied
2025/04/19 01:43:55 ERR [path cam] [RPI Camera source] fork/exec /dev/shm/mediamtx-rpicamera-1745027034840747118/mtxrpicam: permission denied
2025/04/19 01:44:00 ERR [path cam] [RPI Camera source] fork/exec /dev/shm/mediamtx-rpicamera-1745027040121366542/mtxrpicam: permission denied
^C2025/04/19 01:44:03 INF shutting down gracefully
2025/04/19 01:44:03 INF [SRT] listener is closing
2025/04/19 01:44:03 INF [WebRTC] listener is closing
2025/04/19 01:44:03 INF [HLS] listener is closing
2025/04/19 01:44:03 INF [RTMP] listener is closing
2025/04/19 01:44:03 INF [RTSP] listener is closing
2025/04/19 01:44:03 DEB path manager is shutting down
2025/04/19 01:44:03 INF [path cam] [RPI Camera source] stopped: path is closing
2025/04/19 01:44:03 DEB [path cam] destroyed: terminated
2025/04/19 01:44:03 INF waiting for running hooks

[aler9]

Sorry but we don't support running MediaMTX on BalenaOS. I mean, you are free to do it, but don't expect support for it. From what i see in logs there are some troubles when executing something from the /dev/shm folder, so you should check whether it's actually possible to execute anything from that folder, in a container, independently from MediaMTX.