Good tutorial.
By the way, although it's possible that "No Brain Required" to run a witness node, it's not recommended that people doing it without a brain. Witnesses (especially the top 19) need to help provide useful info when something happens, to track down the issue and fix it, but not only upgrade to latest code when released or even after several hours.
//Edit: looks like you're running all things with the root account, it's not so good. @bitcalm's tutorial is better from a technical POV.
I've yet to revise this to explain proper procedure in locking down the server properly to maintain the highest possible security levels. When I started writing this guide I had no idea it wold get so lengthy and I'll have to go back and add some things I've noticed when I get a chance to.