Atomic unit of work in Kubernetes They are the application/service Can contain multiple containers Pods cannot be created/destroyed, only instantiated Pod lifecycle -> pending, ready, failed/succeeded Pods are instantiated by Kubelet in the worker nodes Pods can be scaled up/down Pods have unique IPs Containers within a Pod share namespace resources like network, mount, IPC, etc Therefore containers within a Pod can share files and communicate with each other via localhost Pods communicate with each other (with other pods) using

Kuberenetes consists of a master, worker nodes and workstation (pc that developer uses to send commands to control plane/master) Master has the following components: API Server (Communicates with every other component in the control plane aka master) Etcd (Cluster store -> stores information about the cluster (The desired state)) Controller Manager (Probes all the pods in the cluster to check for their health) Scheduler (Schedules tasks that are to be executed by the worker nodes) Worker has the following components:

It’s a collection of filesystems, namely => rootfs, user fs, application fs These filesystems are represented as layers. Therefore each docker image has multiple filesystems, that is, each docker image has multiple layers Each layer is identified by a uuid, which is sha256 encoded. The lowest layer is the root filesystem. That is, it contains files under root directory The upper most layer is the only layer which is writeable, rest all layers are readonly Whenever you create any new