# [[Key characteristics of Kubernetes]] Below are things that differentiate [[Kubernetes]] from other [[Container Orchestration Engines]]. ### Declarative, not imperative Despite the fact that it is usually called an orchestration engine, Kubernetes actually eliminates the need for orchestration entirely. It employs [[Declarative]] manifest files that control processes use to get closer and closer to the ideal state, rather than carrying out [[Imperative]] instructions. [^whatis] ![[What Is Kubernetes#^150481389]] ### Pods are atomic A pod is a single, [[Principle of Atomicity]] instance of an application deployed on Kubernetes. It can contain one or more [[Containerization|containers]], but most commonly holds just one. A pod is a specific type of virtual machine created by Kubernetes, and each on is assigned a unique IP address. In a situation where many containers are in the same pod, the containers are the most atomic element in the system. However, this is an advanced and uncommon use case. Multiple containers in one pod share resources, so it is useful for applications that need to share storage, for example. ### A cluster manages pods A cluster is a group of pods that are deployed and managed together, and often are replicas of each other. A cluster monitors the health of pods and scales them up or down as necessary. ### Pods are ephemeral When a pod becomes unhealthy or unresponsive, the pod is simply terminated and a replica of it is created. This simplifies troubleshooting considerably. You should [[Infrastructure as cattle, not pets|treat pods as cattle, not as pets]] [^sidpalas]. Don't call them names; don't treat them like they're special, because they're not. Treat them like resources that will be replaced at some point. If you need to make a change, make a change to the definition files, not to the pod or node itself. [^whatis]: Kubernetes.io. _What is Kubernetes?_. Retrieved from https://kubernetes.io/docs/concepts/overview/what-is-kubernetes/ [^sidpalas]: Palas, S. (2021). _k6 office hours with Sid Palas_. [YouTube](https://www.youtube.com/watch?v=bYdDRZqRSHA).