What is the Kubernetes API server?

Question

Accepted Answer

**API server** — central management entity that processes REST operations.

**Responsibilities:**
- Serves the Kubernetes API.
- Authenticates and authorizes requests.
- Validates and stores objects in etcd.
- Watches for changes.

```bash
# Access API server
kubectl cluster-info
kubectl api-resources
kubectl api-versions

# Direct API call
kubectl get --raw /healthz
kubectl get --raw /metrics

# Debug API server
kubectl logs -n kube-system kube-apiserver-node1
```

**Admission controllers:**
- MutatingAdmissionWebhook — modify objects.
- ValidatingAdmissionWebhook — validate objects.
- PodSecurity — enforce security policies.

DevOps: What is the Kubernetes API server?