前言

前面安裝好kubelet, kubeadm, kubectl了，接下來來實施並驗證Kubernetes功能。

4. Turn off swap area

swapoff -a

change DNS server

vim /etc/resolv.conf

nameserver 8.8.8.8

5. Initializing your master and create a cluster

kubeadm init --pod-network-cidr=10.244.0.0/16

6. To start using your cluster, you need to run the following as a regular user

mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

7-1. Node isolation (Single Node)

kubectl taint nodes --all node-role.kubernetes.io/master-

7-2. Join your node

kubeadm join <master-ip>:<master-port> --token <token> --discovery-token-ca-cert-hash sha256:<hash>

8. Installing a pod network add-on (CNI Plugin - Flannel)

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/62e44c867a2846fefb68bd5f178daf4da3095ccb/Documentation/kube-flannel.yml

9. Check your master node is ready

kubectl get node
or 
watch kubectl get node

4. Implement and verify Kubernetes feature

1. Create a Deployment based on the YAML file

wget https://k8s.io/examples/application/deployment.yaml
kubectl apply -f deployment.yaml

2. Display information about the Deployment

kubectl describe deployment nginx-deployment

3. Display information about a pod

kubectl get pod
kubectl describe pod nginx-deployment-xxx-xxx

4. Change deployment replica

kubectl edit deployment nginx-deployment

watch kubectl get pod 

5. Change deployment image version

kubectl edit deployment nginx-deployment

watch kubectl get pod

6. Test self-heal

kubectl get pod
kubectl delete pod nginx-deployment-xxx-xxx

watch kubectl get pod

7. Create a service resource

cat <<EOF > service.yaml
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  selector:
    app: nginx
  ports:
  - protocol: TCP
    port: 80
  type: NodePort
EOF

kubectl apply -f service.yaml

8. Look your service NodePort

kubectl get service

9. Use web browser to watch your service on Kubernetes, Enter on URL :

http://10.27.4.x:3xxxx

10. Edit web file to verify that is load balance

kubectl exec -it nginx-deployment-xxx-xxx bash

echo 1 >> /usr/share/nginx/html/index.html
echo 2 >> /usr/share/nginx/html/index.html
echo 3 >> /usr/share/nginx/html/index.html
...

11. Edit deployment.yaml

vim deployment.yaml

...
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80
        volumeMounts:
        - name: web-persistent-storage
          mountPath: /usr/share/nginx/html/
      volumes:
      - name: web-persistent-storage
        persistentVolumeClaim:
          claimName: web-pv-claim
          
kubectl apply -f deployment.yaml

12. Add a volume on web path

cat <<EOF > pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: web-pv-claim
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi
EOF

cat <<EOF > pv.yaml
kind: PersistentVolume
apiVersion: v1
metadata:
  name: web-pv-volume
  labels:
    type: local
spec:
  capacity:
    storage: 20Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/"
EOF

kubectl apply -f pv.yaml
kubectl apply -f pvc.yaml

13. Add a index.html in /mnt/

cd /mnt/

cat <<EOF > index.html 
<input what you want>
EOF

參考連結

• https://zh.wikipedia.org/wiki/Kubernetes
• https://kubernetes.io/
• https://www.docker.com/resources/what-container