I (Fabrizio) was following a thread on Reddit (https://www.reddit.com/r/docker/comments/4zous1/monitoring_containers_under_112_swarm/) in August 2016, where users complained that the new Swarm Mode is harder to monitor.
If, for now, there are no official Swarm monitoring solutions, one of the most popular combinations of emerging technologies is: Google's cAdvisor to collect data, Grafana to show graphs, and Prometheus as the data model.
The team at Prometheus describes the product as:
Prometheus is an open-source systems monitoring and alerting toolkit originally built at SoundCloud.
Prometheus's main features are: