This seems a lot to me like Docker Inc. caving in to what has been painfully obvious for a while: K8s won and Swarm/Mesos lost the battle for hearts and minds in container orchestration. We can argue about why it happened, but I got the impression Docker Inc. were desperately trying to wish it away.

Now reality has intruded and I am glad, though I predict they'll continue to maintain that Swarm is a first class platform for a while, then quietly let it wither on the vine until one day it's forgotten about.

Also of note is Rancher 2.0's dropping support for Swarm and Mesos and focusing solely on K8S going forward.