Metrics and monitoring are related but not the same. Coda Hale has defined much of this field in a very generic way. Crowley ported hist ideas to go. As I construct services on bare metal, VPS, and containers I have varying needs for my OPS role. In the past I have used rddtool and graphite. Both projects are rock solid but they are starting to show their age. Not to mention there have been some projects that modernize the market.
Go-metrics is a good project because it upgrade the glossary of terms so that it’s usage and context is clear where it’s predecessors was not as clear, however, it does not offer any sort of visualization.
OpenTSDB - Open Time Series Data BaseThe prometheus project is an open source project from the prometheus team. it’s offered under the Apache 2.0 so it’s favorable, however, other than Google images I don’t see any application examples. (I thought prometheus was from soundcloud but it seems I’m mistaken).