Core objects you deploy
| Object | What it is |
|---|---|
| Pod | Smallest deployable unit — one or more containers sharing network/storage. |
| ReplicaSet | Keeps a set number of identical Pods running. |
| Deployment | Manages ReplicaSets — rolling updates and rollbacks. |
| Service | Stable network endpoint and load balancing for a set of Pods. |
| Ingress | HTTP(S) routing from outside the cluster to Services. |
| ConfigMap / Secret | Inject configuration / sensitive data into Pods. |
| Namespace | Virtual cluster partition for isolation and quotas. |
Cluster architecture
| Control plane | Worker node |
|---|---|
| kube-apiserver — the front door/API | kubelet — runs Pods on the node |
| etcd — cluster state key-value store | kube-proxy — node networking/Service routing |
| kube-scheduler — assigns Pods to nodes | container runtime — e.g. containerd |
| controller-manager — reconciles desired state |
Exam traps
- Deploying Pods directly. Use a Deployment so failed Pods are recreated.
- Secret = encrypted by default. Secrets are base64-encoded; enable encryption at rest.
- Service vs Ingress. Service exposes Pods (L4); Ingress does HTTP routing (L7).
- etcd is optional. It holds all cluster state — losing it loses the cluster.
Test yourself
4 quick questions — tap an answer to check it instantly. Nothing is sent anywhere.
1. The smallest deployable unit in Kubernetes is a…
Answer: B. A Pod (one or more containers sharing network/storage) is the smallest unit.
2. Which component stores all cluster state?
Answer: B. etcd is the key-value store holding all cluster state.
3. For rolling updates and self-healing Pods, you use a…
Answer: B. A Deployment manages ReplicaSets for rolling updates and recreates failed Pods.
4. Which runs on every worker node to manage its Pods?
Answer: B. The kubelet runs on each worker node and manages its Pods.
Sources
- The Kubernetes Authors — Kubernetes Concepts documentation.
Reference summary only. See kubernetes.io for authoritative documentation.