Why should a production Kubernetes cluster have a minimum of three nodes? : <p>The <a href="https://kubernetes.io/docs/tutorials/kubernetes-basics/cluster-intro/" rel="noreferrer">first section</a> of the official Kubernetes tutorial states that,</p>

<blockquote>
  <p>A Kubernetes cluster that handles production traffic should have a minimum of three nodes.</p>
</blockquote>

<p>but gives no rationale for why three is preferred. Is three desirable over two in order to avoid a split-brain scenario, to merely allow for greater availability, or to cater to something specific to the internals of Kubernetes? I would have thought a split-brain scenario would only happen with multiple Kubernetes clusters (each having distinct masters) whereas a single cluster should be able to handle at least two nodes, each, perhaps, in their own availability-zone. </p>
