5. Security hardening
I find it is easier to deploy Hadoop in a fairly low security configuration. This is because there are a range of ports that Hadoop talks on and having an incorrectly configured firewall can cause you problems. So after deployment, set aside time to identify how to customise your firewalls, user and group settings, Kerberos and ssl settings.
I think the article makes some good points. DIY is great for a proof of concept or for playing around with a technology, but if you don’t already have a good amount of experience with a technology, you’ll probably make costly mistakes in development and administration. This is not Hadoop-specific: I’ve seen companies do terrible things to SQL Server because they didn’t know the correct way to do it but needed to get work done. As part of a proof of concept, do all the terrible things you’d like; they’re how you’ll learn. But if this is going to production, it’s a good idea to have people who know what they’re doing involved.