Once upon a time, there was a lonely elephant. He wanted to play with other elephants, but there were none around to play with. One day, a man came to town with an elephant. That elephant was named Hadoop. Hadoop wasn’t a normal elephant, no. He was a clustering elephant. Our lonely elephant will be lonely no more.
Soon, Hadoop had a cluster of elephants around him. Some of those elephants didn’t play all the time, but that was ok for our lonely elephant, he had many more to play with. Whenever our friend wanted to play, he would go to the closest elephant to him. An elephant would sometimes be sleeping, busy with other activities, or sick and couldn’t deal with other elephants that day. Our lonely elephant felt bad for the sick cluster elephant, but would go to the next available cluster elephant. There were thousands. And each behaved just like the other. It was so much fun for our friend.
He wasn’t lonely any more.

Story loosely based on the concept of apache hadoop.