Chapter 15: Kubernetes Introduction
15.3 Core objects — Pod, Deployment, Service, Namespace
| Object | Plain English | Real-world picture |
|---|---|---|
| Pod | Smallest deployable unit; one or more containers sharing network namespace | One small app unit |
| Deployment | Declares replica Pods + rolling update strategy | Manager keeps N replicas running |
| Service | Stable way to reach Pods (ClusterIP / NodePort / LoadBalancer) | Stable address for the pods |
| Namespace | Virtual cluster slice for isolation | Separate floor for lab vs demo |
Deployment
└── ReplicaSet (you rarely edit by hand)
└── Pod(s)
└── Container(s)
Service ----selects----> Pods (by labels)
Labels and selectors glue Service → Pods. Misspelled labels = Service with no endpoints — classic beginner bug.