🛠 Docker dès la sortie de l'emballage : premier conteneur sur le Linux embarqué

Objectives

The true superpower of the X8: its embedded Linux (Linux microPlatform, Foundries.io Yocto distribution) ships with Docker preinstalled. Applications run in containers decoupled from the OS — modular deployment, incremental OTA, ready-to-use images on the arduino Docker Hub. You will launch your first container, understand the docker permissions story, and pull an official Arduino image.

Hardware

• 1 × Arduino Portenta X8 powered via USB-C
• PC with adb (board visible via adb devices)
• Internet connection on the board's network (Wi-Fi or Ethernet via carrier board — see the network tutorial; by default the X8 has no bare RJ45)
• 16 GB embedded eMMC: Docker images fit comfortably

Complete code

# Depuis le PC :
adb shell
# fio@portenta-x8:~$

# Permission docker : la doc officielle recommande d'abord :
newgrp - docker

# Le test canonique, fonctionne out of the box :
docker run hello-world
# -> "Hello from Docker! This message shows that your installation...

# Images officielles Arduino sur Docker Hub (org « arduino ») :
docker pull arduino/python-rpc-serial

# Lancer le conteneur officiel du tuto python-arduino-data-exchange :
docker run -d \
  --name python-rpc-serial \
  --restart unless-stopped \
  -e PYTHONUNBUFFERED=1 \
  --tty \
  --read-only \
  -p 5002-5020:5002-5020 \
  -v /tmp:/tmp \
  --device /dev/ttyGS0 \
  arduino/python-rpc-serial

# Inventaire local
docker images
docker ps -a

Expected verification

docker run hello-world displays the welcome message in a few seconds (download included) — proof that the Docker daemon, eMMC storage, and network are working. The arduino/python-rpc-serial container starts in the background (docker ps lists it as "Up"): it exposes RPC ports 5002-5020 and the serial device /dev/ttyGS0, the gateway to the M4 sketch in the next tutorial.

Common errors

• permission denied on /var/run/docker.sock: this is THE documented pitfall — run newgrp - docker in your adb session before any docker command (otherwise switch to root).
• Believing that containers persist after deleting an image: docker rm + docker rmi really delete them; to return to a clean system, the official procedure is reflashing the image (image-flashing tutorial).
• docker pull failing: no network! The bare board has neither RJ45 nor an Ethernet cable — first verify that Wi-Fi or Ethernet on the carrier board is mounted (network tutorial).
• A --read-only container complaining when writing to /tmp: this is why the official image mounts -v /tmp:/tmp as read/write — do not remove this mount.
• Confusing it with a Raspberry Pi: here there is no apt or RaspiOS, it is Yocto; system packages are managed at image build time (or opkg for test packages), not with a classic package manager.
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