Pod Theory
The atomic unit of scheduling in the virtualization world is the Virtual Machine (VM). This means deploying applications in the virtualization world requires scheduling them on VMs.
In the Docker world, the atomic unit is the container. This means deploying applications on Docker that is deploying them inside of containers.
In the Kubernetes world, the atomic unit is the Pod. Ergo, deploying applications on Kubernetes means stamping them out in Pods.
This is fundamental to understanding Kubernetes, so be sure to tag it in your brain as important: virtualization does VMs, Docker does containers, and Kubernetes does Pods:
Figure 4.1: Atomic units of scheduling
As Pods are the fundamental unit of deployment in Kubernetes, it's vital we understand how they work.
Note
We're going to talk a lot about Pods in this chapter. However, it's important to remember that Pods are just a vehicle for deploying applications.
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