We need to enabled 'networkd' for systemd because it serves as a reasonable network configuration method. Reasons: ------------ 1. systemd-networkd provide a sensible default, with it, the user could easily configure some simple networking. In sysvinit, users can configure their network by editting /etc/network/interfaces. Such configuration could take effect at boot time. It is done via /etc/init.d/networking script. Of course, the users could configure their networking via other tools. But '/etc/init.d/networking + ifupdown' provides a sensible default for sysvinit. In systemd, we also need a sensible default which should provide the same functionality with '/etc/init.d/networking + ifupdown'. And that is 'networkd'. 2. systemd-networkd has no negative effect. There's no boot time impact. And if there's no custom configuration files, systemd-networkd almost does nothing. 3. It can work with other network configuration tools. 4. If the users don't like it, they can disable it by `systemctl disable systemd-networkd'. In summary, with 'networkd', we are providing a basic networking functionality which has no negative impact. So I'd suggest we enable it by default in our bbappend file. //Chen Qi
