Update host MOTD when agent is running

[invidian]

Original issue: https://github.com/coreos/container-linux-update-operator/issues/88

Sounds like a cool and useful idea. This may require some development on Flatcar to get working nicely.

[pothos]

FLUO needs to create a /run/update-engine/coordinator.conf file. See the code in /usr/share/baselayout/flatcar-profile.sh for the details: Locking the file seems to be required and it should contain something like this:

STRATEGY=reboot
STATE=running
NAME=fluo

(Just having STATE and NAME seems to be enough.)

[invidian]

Thanks @pothos! That should be super easy to implement then :smile: