This article contains potentially harmful advice. I would never expose my eyes to direct sunlight - The risk of permanent retinal damage is insanely high, even if you gaze at the sun for a few seconds straight.
I was an user of zeppelin for a couple of years (v0.7-0.8), we used it to run Scala Spark and the UI has a lot of bells and whistles to make it easier to use Spark, display spark dataframes and simple dataviz features out-of-the-box. It is a bit relatable to the notebook experience you would have in databricks.
The one and only. Still online to my surprise.