A symlink from avahi-daemon.service to dbus-org.freedesktop.Avahi.service in /usr/lib/systemd/system is missing. systemd is unable to start the service when a request for Avahi is sent over DBus. Please see the Arch bug for details. Creating the link helps. Reproducible: Always
I confirm this, Arch fixed it some time ago creating the link manually: https://projects.archlinux.org/svntogit/packages.git/tree/trunk/PKGBUILD?h=packages/avahi
+*avahi-0.6.31-r8 (13 Jul 2015) + + 13 Jul 2015; Pacho Ramos <pacho@gentoo.org> +avahi-0.6.31-r8.ebuild, + metadata.xml: + Add symlink needed for starting avahi properly on systemd (#537000) +
(In reply to Łukasz Stelmach from comment #0) > A symlink from avahi-daemon.service to dbus-org.freedesktop.Avahi.service in > /usr/lib/systemd/system is missing. systemd is unable to start the service > when a request for Avahi is sent over DBus. If you want Avahi to be activated via dbus, just enable avahi-daemon.service and necessary symlink will be created in /etc/systemd/system. If avahi-daemon.service is not enabled, then Avahi will not be started at all. I think this upstream behaviour is expected behaviour and ebuild should not manually create symlink in /usr/lib/systemd/system. $ grep Alias /usr/lib/systemd/system/avahi-daemon.service Alias=dbus-org.freedesktop.Avahi.service $ sudo systemctl reenable avahi-daemon.service Removed symlink /etc/systemd/system/multi-user.target.wants/avahi-daemon.service. Removed symlink /etc/systemd/system/sockets.target.wants/avahi-daemon.socket. Removed symlink /etc/systemd/system/dbus-org.freedesktop.Avahi.service. Created symlink from /etc/systemd/system/dbus-org.freedesktop.Avahi.service to /usr/lib/systemd/system/avahi-daemon.service. Created symlink from /etc/systemd/system/multi-user.target.wants/avahi-daemon.service to /usr/lib/systemd/system/avahi-daemon.service. Created symlink from /etc/systemd/system/sockets.target.wants/avahi-daemon.socket to /usr/lib/systemd/system/avahi-daemon.socket.
I have reverted the sym link because of bug #567798. Please wait for my ack before committing changes as I'd like to keep up with what is happening to avahi.