Ok. let's keep it short!
Kubernetes cluster is a collection of machines, each machine has a dedicated role. They can be master or worker. The master is our API point of contact and holds the information about what's going on in the cluster in terms of apps, pods, developments, etc. The workers are in charge of running the app in the pod, in the container.
The machines that acts as workers, used to be called
Today they are called nodes.
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