Once upon a time there was a unicorn. The unicorn was extremely lean and agile, and yet she was lonely. That is because she lived in the land of the horses.
Oddly enough, the horses were all kept in silos, rather than corrals or stables. When they wanted to communicate with each other, they just threw things over the walls of the silos. This also was odd, as, since silos have roofs, you would think the things they were throwing would just bounce back down on their heads. But such was their legacy.
In any case, the horses were let out occasionally during the day, but usually only got to graze on brownfields, and almost never got to see a nice greenfield. They ought to have been out playing resiliently in an ecosystem, but instead were trapped in an unresponsive echo chamber. And so the lonely unicorn sat in her silo, day after day, dreaming of the greenfields.
She might be sitting there still, but one day a magical chef, along with his equally magical puppet, and his servant, named Jenkins, arrived at the silos.
"Hello, lonely unicorn," the magical chef said, "would would you like to visit the beautiful, RESTful greenfields, and graze on their very enabling feature sets?"
"Would I ever, " exclaimed the lonely unicorn, "but how could I do that?"
"Well," replied the magical chef, "I have just the recipe for you! All you need to do is to git into my machine here. It will open up seams in your silo, and provide you with silver bullets that you can turn in for free lunches and golden hammers in the greenfields."
"But I don't see any machine!" responded the lonely unicorn.
"Ah, that's because it is a virtual machine!" the magical chef replied. "It only exists if you are willing to completely buy in!"
"Okay, I buy in," said the lonely unicorn, as she stepped into the virtual machine.
But, to her great dismay, nothing happened. "What's wrong?" she asked, "I don't see the greenfields."
"Well," replied the magic chef, "that is because your cost profile is still too high for you to fit through the seams. But inside the virtual machine is a magical container. If we containerize you, we can reduce your cost profile enough that you can be deployed through one of the seams."
"Ah, now I get the kernel of the idea," said the lonely unicorn. She climbed into the container, and found that inside, there was a name space that was built especially for her. Her cost profile having shrunk by an order of magnitude, she could now be deployed to the greenfields, hundreds of times a day, if she wished, where she could elastically frolic with the many other unicorns, and never, ever have to throw anything over a silo wall again!
And so she lived happily ever after.