Marlin Firmware and Jenkins

I have a 3d printer that uses the Marlin firmware. It’s an Alunar M508 (Prusa I3 Clone) and I maintain a build of Marlin for it that is tailored for that printer. Recently, I thought it would be fun to set up a Jenkins build agent that can build Arduino code. The agent is a docker image that is based off a base sshd image. Currently these are not available publicly, but I may change that in the future.

The base image is just a standard sshd server so so Jenkins can communicate to the agent.

The arduino agent installs arduino 1.8.5, and a few things like pip, gcc, etc. I also have some scripts that I put together that allow the build pipeline install Arduino Boards and Libraries. Like the board and library managers in the UI.

board-manager --name='Arduino AVR Boards' --version='latest' --packager='arduino'

That command will install the latest AVR boards and all the required dependencies. Additionally, to install a libarary, it would look like this:

library-manager --name='LiquidCrystal' --version='latest';

After I got all that setup and able to output the hex binaries from the arduino-builder, I thought it would be fun if I could trust that the build that came out flashes to a device successfully. I pulled out the extra Mega2560 board I have that I use for testing my builds of the firmware anyhow before I would flash it to the printer, and I plugged it in to my Docker Host. The Jenkins Arduino agent mounts that device so it can access it.

After the binaries are built, I run:

avrdude -p m2560 -c avrispmkII -P /dev/ttyACM0 -C /usr/local/etc/avrdude.conf -D -U flash:w:/path/to/build.hex:i

Which will write the binary to the device. After that is successful, I run some serial commands to actually read from the Firmware to validate that it is announcing / working as Marlin.

After that is successful, it will zip up the hex files, and it creates a Github release and uploads the file to the release.

You can find most of the “work” in the github repo in either the Jenkinsfile, or the .deploy scripts folder. I still have some issues to iron out, like making sure the serial port is available again after the push to the device. After I get that stuff wrapped up, I will see what I have to adjust to make the container images publicly available.

Setting up Artifactory as Docker Registry

I was setting up artifactory as a docker registry on-premises with a self-signed certificate. This was not as simple as some of the docs suggested. It took me a bit to put together the process for this as it wasn’t really laid out in any single place. Here is what I did to get it working.

Distro: Ubuntu 16.04

I decided to do the subdomain method for setup. my FQDN that I will be subdomaining off of is artifactory.contoso.com. Each subdomain will be a different registry within artifactory. This will assume you already have an NGINX  instance setup to do the reverse proxy with the configuration defined by the Artifactory Reverse Proxy Generator.

Create self-signed certificate. I store mine in /mnt/data/ssl

$ openssl req -newkey rsa:2048 -nodes –keyout /mnt/data/ssl/wildcard.artifactory.contoso.com.key -x509 -days 365 –out /mnt/data/ssl/wildcard.artifactory.contoso.com.cert

Need to make this certificate available for docker

# mkdir –p /etc/docker/certs.d/wildcard.artifactory.contoso.com;
# cp /mnt/data/ssl/wildcard.artifactory.contoso.com.key /etc/docker/certs.d/wildcard.artifactory.contoso.com/domain.key;
# cp /mnt/data/ssl/wildcard.artifactory.contoso.com.cert /etc/docker/certs.d/wildcard.artifactory.contoso.com/domain.cert;
# ln –s /etc/docker/certs.d/wildcard.artifactory.contoso.com /etc/docker/certs.d/docker.artifactory.contoso.com; 
# ln –s /etc/docker/certs.d/wildcard.artifactory.contoso.com /etc/docker/certs.d/docker-local.artifactory.contoso.com;

Now we have a folder setup for each subdomain for each docker registry in Artifactory. Next we need to add the certificates so the CA is known by the system.

# cp /mnt/data/ssl/wildcard.artifactory.contoso.com.key /usr/local/share/ca-certificates/wildcard.artifactory.contoso.com.key;
# cp /mnt/data/ssl/wildcard.artifactory.contoso.com.cert /usr/local/share/ca-certificates/wildcard.artifactory.contoso.com.crt;
# update-ca-certificates;

Next we need to add the domains to the docker options to allow them to be insecure.

# nano /etc/init.d/docker
### EDIT ###
DOCKER_OPTS="$DOCKER_OPTS --insecure-registry docker.artifactory.contoso.com  --insecure-registry docker-local.artifactory.contoso.com

Finally, we just need to restart docker.

# systemctl restart docker

YMMV, but these are the steps that I needed to do to get things working for me.

User Docker Agents with Jenkins

I am running Jenkins in my home lab in docker container. I wanted to also have different agents for the different types of projects I was building, like building some of my Arduino projects for the different boards I have, or nodejs packages, etc.

I have the Jenkins Cloud Plugin and docker-plugin installed. I was having some issues configuring it to connect to the docker api, and the plugin documentation is out dated.

Since this is my lab, I just set up for TCP communication vs the docker.sock. The documentation says to edit the /etc/init/docker.conf. Except on Ubuntu 16.04 that is not used.

Instead, you have to edit /lib/systemd/system/docker.service and add -H 0.0.0.0:32376 to ExecStart.

Run systemctl daemon-reload

And finally, systemctl restart docker

Now docker engine will restart and it will be listening on port 32376. If you do curl –XGET http://localhost:32376 you should get a response.

You can now configure jenkins to use tcp://<docker-host>:32376 and hit test connection.