Why does this thing exist?

  To speed up my development and prototyping workflow

What does this thing do?

  Automates the steps that I'd otherwise have to perform manually to 
  install/configure/teardown services, using a consistent & repeatable process.
  That is all

What the heck is it?

  It's just a couple of scripts that provide a pluggable framework for doing
  whatever you want with any application that can be bootstrapped via bash
  
  You can pick/choose which service plugins you want activated, modify existing
  plugins, or create new plugins without much hassle

  Currently you get Hadoop, Accumulo, and NiFi plugins out of the box. Standalone
  single-node cluster configuration is implemented. Multi-node options coming soon

Prerequisites

  None other than Linux/Bash, and an Internet connection to wget tarballs.
  Tested on CentOS 7. *Should* be fine on any Linux with Bash 4.x

What does this thing do that something like Docker or Cloudera Manager couldn't do even better?

  Nothing. However, dependencies and complexities here are minimal compared with
  those. Applications built on Hadoop and Accumulo have complex networking and IPC
  requirements, which makes them challenging to implement with containers.
  And as far as Cloudera Manager goes, sadly, I've spent far less time implementing this
  thing than I've spent trying to decipher Cloudera's documentation.

  That being said, I do love Docker ;)

How do I get started?

(1) Edit ~/.bashrc: 
    Source env.sh in your ~/.bashrc. E.g...
    echo "source /path/to/this_dir/bin/env.sh" >> ~/.bashrc

(2) Download tarballs: 
    Open a new terminal... 
    Tarballs for any registered services (in this case, Hadoop, Accumulo/ZooKeeper,
    and NiFi) will begin downloading immediately. If desired, update '*_DIST_URI' 
    variables to affect which app versions get downloaded
  
(3) Install services:
    When downloads are finished, execute the "installAll" command

(4) Start services:
    When installs are finished, execute the "startAll" command

(5) To check the status of services, execute the "statusAll" command.
    And visit some websites in your browser...

       Hadoop: http://localhost:50070/dfshealth.html#tab-overview
     Accumulo: http://localhost:50095
         NiFi: http://localhost:8080/nifi/

(6) Do more stuff. Let the real work begin

How do I stop doing stuff?

(1) To stop services, execute the "stopAll" command
(2) To uninstall services, execute the "uninstallAll" command

How do I find out more?

Read some code. There's about a 41% chance that it'll have some useful comments. 
Start with bin/env.sh. It's the key to everything else