Summary - What is Kubernetes
- Docker & Kubernetes course
- Intermediate
- Lesson 6/82
- 5 min
Combine cluster components to write an architecture description.
Summary: what Kubernetes is
In this group:
- Kubernetes runs, scales and heals containers on a cluster according to the desired state.
- Objects are defined declaratively in YAML and applied with
kubectl apply. - Control plane: kube-apiserver, etcd, kube-scheduler, kube-controller-manager.
- Worker node: kubelet, container runtime (containerd), kube-proxy.
kubectl get nodes/pods -o wide,describe,topandcluster-infoare the basic commands for inspecting a cluster.
kubectl get nodes
kubectl get pods -A -o wide
kubectl top nodesPractice A cluster tour
Write three commands: list the nodes; list the pods in all namespaces in wide format; scale the web deployment to 2 replicas.
Starter code
# buraya yazSample solution
kubectl get nodes
kubectl get pods -A -o wide
kubectl scale deployment web --replicas=2Expected output
NAME STATUS ROLES AGE VERSION minikube Ready control-plane 2d v1.31.2 NAMESPACE NAME READY STATUS IP NODE default web-7c5b9f6d8-abcde 1/1 Running 10.244.0.5 minikube kube-system etcd-minikube 1/1 Running 192.168.49.2 minikube deployment.apps/web scaled
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which component picks the node for a new pod?
- kube-scheduler Correct answer
- kubelet
- etcd
- kube-proxy
Explanation: The kubelet then starts the pod on the chosen node.
2 List the pods in all namespaces.
Question
kubectl get pods ____
Answer
kubectl get pods -AExplanation: -A (--all-namespaces) covers all namespaces.
3 Match.
| Term | Meaning |
|---|---|
etcd |
Control plane |
kubelet |
Worker node |
kubectl apply |
Declarative |
kubectl scale |
Replica count |