Introducing Kubernetes concepts

At a high level, as a container orchestrator, Kubernetes makes a cluster of (physical or virtual) servers that runs containers appear to be one big logical server running containers.

As an operator, we declare a desired state to the Kubernetes cluster by creating objects using the Kubernetes API. Kubernetes continuously compares the desired state with the current state. If it detects differences, it takes action to ensure that the current state is the same as the desired state.

One of the main purposes of a Kubernetes cluster is to deploy and run containers, but also to support zero-downtime rolling upgrades using techniques such as green/blue and canary Deployments. Kubernetes can schedule containers, that is, Pods that contain one or more co-located containers, to the available nodes in the cluster. To be able to monitor the health of running containers, Kubernetes assumes that containers implement a liveness probe. If a liveness probe reports...