Cluster

• Control Plane + Nodes

Namespaces

• virtual clusters backed by the same physical cluster
• a way to divide cluster resources between multiple users

Controllers

• control loops that watch the state of your cluster, then make or request changes where needed
• each controller tries to move the current cluster state closer to the desired state

Node

• physical or virtual machine running Kubernetes services
• components: kubelet, container runtime, kube-proxy

Pod

• a group of one or more containers that share the same storage space and the same network resources
• each pod has a single ephemeral IP address which is shared by all containers running within the Pod
• "one-container-per-Pod" model is the most common Kubernetes use case > a wrapper around a single container
• Kubernetes manages Pods rather than managing the containers directly

Workloads

• apps running on Kubernetes
• built-in workload resources: Deployment, RepicaSet, StatefulSet, DaemonSet, Job, CronJob

Deployment

• a tool that manages the performance and specifies the desired behavior of a pod
• specifies the application’s life cycle, including the pods assigned to the app
• good fit for managing a stateless application workload on your cluster- creating/deleting a deployment automatically creates/deletes it's pod; don't create/delete pods separately

Service

• an abstract way to expose an application running on a set of Pods as a network service
• an abstraction which defines a logical set of Pods and a policy by which to access them
• the set of Pods targeted by a Service is usually determined by a selector
• most commonly abstract access to Kubernetes Pods