Setting up a Raspberry Pi as a Jenkins Agent

This guide will walk you through setting up a Raspberry Pi (or another Linux machine) as a Jenkins agent for Mbed CE

Install build tools

sudo apt-get install aptitude
sudo aptitude install gcc-arm-none-eabi gdb-multiarch cmake ninja-build openocd
sudo ln -s /usr/bin/gdb-multiarch /usr/bin/arm-none-eabi-gdb # Raspbian does not have arm-none-eabi-gdb directly, you have to use it through multiarch

Note: Mbed needs at least CMake 3.19, if you don't have that version or a newer one in your package manager you will need to compile it from source instead.

Set up Jenkins Agent

From here: https://www.gdcorner.com/2019/12/27/JenkinsHomeLab-P2-LinuxAgents.html

sudo aptitude install default-jre
sudo adduser jenkins # and then follow the prompts, can set the password to "jenkins"
sudo su jenkins
mkdir ~/.ssh
nano ~/.ssh/authorized_keys # paste the jenkins agent SSH public key into this file

You can now add the RPi in Jenkins via Manage Nodes and Clouds > New Node

• Remote Root Directory: /home/jenkins
• Labels: <all Mbed targets connected to this node, separated by spaces>
• Launch Method: Launch via SSH
• Host: <IP address of node>
• Credentials: <use the Jenkins node key>
• Host Key Verification Strategy: Manually Trusted

After clicking OK on this screen, the node should be available for use!

Set up udev rules

• Get serial number of Mbed device from its tty:

udevadm info -a -n /dev/ttyACMxxx | grep '{serial}' | head -n1

• Create a file /etc/udev/rules.d/99-usb-serial.rules with contents like:

SUBSYSTEM=="tty", ATTRS{serial}=="<serial number>", SYMLINK+="tty<mbed board>", OWNER="jenkins"

where <mbed board> and <serial number> are replaced by the mbed name and serial number.

• Reload udev:

sudo udevadm control --reload-rules
sudo udevadm trigger

• Create a folder matching the Mbed target name and link the serial port in the location that the build job expects:

sudo mkdir -p /mbed/<target name>
sudo ln -s /dev/tty<target name> /mbed/<target name>/tty

• If using ST-LINK devices, you'll also need the udev rules from here: https://github.com/stlink-org/stlink/tree/develop/config/udev/rules.d