<p>Most of my images that I deploy into Kubernetes has the common base (From) image. So, I have multiple applications deployed into multiple pods. How does the Docker layer cache work across multiple pods, as the From image is same for all the pods?</p>

<p>See "<a href="https://kubernetes.io/docs/concepts/workloads/pods/pod-overview/#how-pods-manage-multiple-containers" rel="noreferrer">How Pods manage multiple Containers</a>"</p>

<blockquote>
  <p>Pods are designed to support multiple cooperating processes (as containers) that form a cohesive unit of service.<br>
  The containers in a Pod are automatically co-located and co-scheduled on the same physical or virtual machine in the cluster.<br>
  The containers can share resources and dependencies, communicate with one another, and coordinate when and how they are terminated.</p>
</blockquote>

<p>So, <strong>within the same cluster</strong>, your pods will share the same container runtime (for instance docker, but others exist).<br>
Which means the layers of your base image will be reused by the various containers running in those pods.<br>
Then each container will write to its special <a href="https://en.wikipedia.org/wiki/UnionFS" rel="noreferrer">UnionFS</a> (which can use one of a few different storage backends, such as aufs or btrfs, there are several choices), using <a href="https://en.wikipedia.org/wiki/Copy-on-write" rel="noreferrer">copy-on-write</a>.</p>
