Glossary

Deployment

Deployments are described as a collection of resources and references. They are the central metaphor for what we would consider "apps" or "services".

Node

A worker machine in Kubernetes; may be a VM or a physical machine, depending on the cluster. Each node contains the services necessary to run pods and is managed by the master components.

Pod

The basic bulding block of Kubernetes. Represents a running process on your cluster; a single instance of an application in Kubernetes. Can consist of a single container or a small selection of tightly coupled containers. Docker is the most commonly used container runtime used in Kubernetes. Pods also represent shared resources for the containers:

• Shared storage, as Volumes

• Networking, as a unique cluster IP address

• Information about how to run each container, such as the container image version or specific ports to use.

Service

Defines a logical set of Pods and a policy by which to access them - sometimes called a microservice. This allows a set of replica Pods to be accessible by other Pods without them needing to worry about which Pod they are accessing; therefore if any of the details of a pod change, for example the IP address of the API endpoint, then it won't break the functionality of the pods trying to access it.

Kubelet

A process that is responsible for communication between the master and a node; it manages the pods and containers running on a node. A node must contain a kubelet.

kubectl

A cli tool that allows us to communicate with our application through an API endpoint. See Kubectl Commands for more.

Label

Labels can be used to group kubernetes objects. For example, we can list all pods that have a particular label, or we can assign a service to only deal with those pods.

Minikube

A utility for easily running kubernetes on your machine. Runs a kubernetes cluster with 1 node in a VM.