<p>I have read a lot about K8s PODs. 
Most of the answers are logical in nature.
Even on k8s.io the definition of a POD is as follows:</p>

<p><em>A Pod is the basic building block of Kubernetes–the smallest and simplest unit in the Kubernetes object model that you create or deploy. A Pod represents a running process on your cluster.</em></p>

<p>I would like to know what the relationship of a K8s POD is with its core implementation components.</p>

Beezer
<p>Best way to answer the question is to look at the K8s codebase, given the answers above:
<a href="https://i.stack.imgur.com/uSWFu.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/uSWFu.png" alt="enter image description here"></a></p>

<p>Here is a snapshot of the Pod*.go listings in the current snapshot of the K8s project. If you look in the <em>container/runtime.go</em> you will see the following:</p>

<p><a href="https://i.stack.imgur.com/XGOlP.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XGOlP.png" alt="enter image description here"></a></p>

<p>Perhaps even more importantly, is the <em>runtime.go</em> interface comments:
<a href="https://i.stack.imgur.com/4r9F4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4r9F4.png" alt="enter image description here"></a></p>

<p>So, it becomes crystal clear, that the runtime of K8s depends on an underlying container runtime that implements the interface for the runtime. In the runtime live the Pods:
<a href="https://i.stack.imgur.com/E3fld.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/E3fld.png" alt="enter image description here"></a></p>

<p>Therefore, the truth of the answer to the question:
<strong>Q> How is a K8s POD Implemented and what is its core implementation components?</strong>
Ans: A K8s Pod is a struct within the K8s runtime-interface that references a group of containers; the core implementation on which a Pod relies is the K8s container-runtime interface that in turn binds to a container-runtime implementation, of which there are many: 
<a href="https://joejulian.name/post/kubernetes-container-engine-comparison/" rel="nofollow noreferrer">https://joejulian.name/post/kubernetes-container-engine-comparison/</a></p>
