ENABLE_AVAHI decides whether dbus and avahi daemons run inside the container or if the host's instances are reused. When set to 0, /var/run/dbus and /var/run/avahi-daemon/socket must be bind-mounted by the user from the host into the container.
Classic (aka AirPlay 1 Only) Docker Image
See the Shairport Sync Docker Hub Repo for available tags.