Your casual tone makes it sound so easy. If only that were true!
Case in point: https://github.com/Shopify/dashing
Here's the presumed knowledge:
* Ruby
* Sinatra
* CofeeScript
* JavaScript
* HTML
* CSS
* SCSS
* Rufus
* Sprockets
Nine different languages and libraries! Jesus H. Christ!It's plain to see why outfits like Splunk can get away with charging as much as they do - visualizing metrics in that app is as simple as installing a deb package, logging in, and pointing it at your data source.
Setting up Dashing by hand is comparatively ...difficult.
There's a much more approachable all-JS Riemann clone called Godot that I've successfully used on multiple projects, but it still requires some work to make the frontend look good.