Network
For bare Docker application, We have to expose port to host machine then another application can access it using hostIP:port. This is find but not suit well in cluster environment like K8s because Pod is considered as ephemeral resource which means its IP isn’t consistent.
Service
Service is an abstraction layer on top of Pod. It helps application client to access application(Pod) without knowing Its location(IP). For external access, see Ingress.
| Feature/Type | ClusterIP | NodePort | LoadBalancer |
|---|---|---|---|
| Access from | Only in cluster using service name | Access using any cluster node IP and specific port | Access using LB IP |
| How to access | serivce-name:port | clusterIP:nodePort | LoadBalanceIP:Port |