balena-io-examples / balena-avahi

mDNS/.local resolution with Avahi within a container

mDNS/.local resolution with Avahi within a container

This example project demonstrates how to install Avahi and nss-mdns in order to resolve *.local hostnames via mDNS within a container.

The motivation behind this example project is that while it is already possible to resolve *.local hostnames from within this balena host OS, currently it is not possible to do that within a container without installing a separate mDNS resolver there.

The part with setting up systemd is taken directly from the Balena Services Masterclass. On top of that the only necessary step is to install Avahi and nss-mdns.

Note: While systemd-resolved provides .local resolution capabilities as well, we recommend using Avahi. The reason is that systemd-resolved depends on systemd-networkd or NetworkManager for its configuration, while Avahi can be used in standalone mode.

balena-avahi's Issues

Windows: Container hangs at "Installing" unless chmod +x on entry.sh

Building and deploying from windows. Container hangs at "Installing" unless I add the following line to Dockerfile.template after the entry.sh COPY command:

RUN chmod +x /usr/bin/entry.sh

Balena Avahi systemd exits

I am looking to leverage balena-avahi/Dockerfile.template so that I can properly resolve *.local addresses - very useful in edge IoT applications. I've followed the example with the only major difference being using balenalib/amd64-python:3.8.11-run as my base image. When the container starts it immediately exits with following error message:

Trying to run as user instance, but the system has not been booted with systemd.

Has anyone gotten systemd to work properly within a container? I see lots of varying examples online.