## K8S筆記

### 在k8s建立pods，第一次輸入視為create，之後info會提示是否update

docker run -t

kubectl apply -f <file name or directory> ==kubectl apply -f pod.yaml==

### 列出pod列表
kubectl get pods

### 列出所有列表
kubectl get all

### 將本地端口轉發到k8s集群端口
kubectl port-forward TYPE/NAME [options] [LOCAL_PORT:]REMOTE_PORT ==kubectl port-forward pod/auth-service 8080:80==

### 修改config後apply,查看更新狀況,一直沒成功會time out
kubectl rollout status deployment auth-service-deployment

### 重啟pod
kubectl rollout restart deployment <deployment_name> -n <namespace>

### 服務有異常，回滾至上個版本
kubectl rollout undo deployment auth-service-deployment --record

### 回滾至指定版本
kubectl rollout undo deployment auth-service-deployment --to-revision=1 --record

### 列出所有port-forward process
ps -ef|grep port-forward

### 停止監聽process
kill -9 <process number>

### 進入容器
kubectl exec -it POD_NAME -- sh

### 刪除namespace底下的所有容器
kubectl delete ns NAME_SPACE

:::info
### 下載dashboard

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.5.1/aio/deploy/recommended.yaml

### 開啟API Server
kubectl proxy

### 生成token
kubectl apply -f - <<EOF
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: kube-system-default
labels:
k8s-app: kube-system
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: cluster-admin
subjects:
- kind: ServiceAccount
name: default
namespace: kube-system

---

apiVersion: v1
kind: Secret
metadata:
name: default
namespace: kube-system
labels:
k8s-app: kube-system
annotations:
kubernetes.io/service-account.name: default
type: kubernetes.io/service-account-token
EOF

打印token
TOKEN=$(kubectl -n kube-system describe secret default| awk '$1=="token:"{print $2}')

kubectl config set-credentials docker-desktop --token="${TOKEN}"

echo $TOKEN
:::

## 透過Ingress實現nginx
### 透過.yaml安裝
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v1.2.1/deploy/static/provider/cloud/deploy.yaml

### 範例

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
spec:
  ingressClassName: nginx
  defaultBackend: <!-- 在沒有規定其他port號下，預設會導向odin-service的8000port -->
    service:
      name: odin-service
      port:
        number: 8000

apiVersion: v1
kind: Service
metadata:
  name: odin-service
spec:
  selector:
    type: demo
  type: NodePort
  ports:
    - protocol: TCP
      port: 8000
      targetPort: 80
      nodePort: 30390

:::warning
==Deployment "auth-service-deployment" is invalid: spec.selector: Invalid value: v1.LabelSelector{MatchLabels:map[string]string{"type":"demo1"}, MatchExpressions:[]v1.LabelSelectorRequirement(nil)}: field is immutable==
當更改selector,需要刪除服務在新建
:::

// deployment.yaml
    
apiVersion: apps/v1
kind: Deployment
metadata:
  name: chat-service-deployment
  labels:
    type: chat-demo
spec:
  replicas: 1
  selector:
    matchLabels:
      type: chat-demo
  template:
    metadata:
      labels:
        type: chat-demo
    spec:
      restartPolicy: Always //default
      containers:
        - name: chat-service
          image: odinveve/chat-service
          ports:
            - containerPort: 8080

- Always: Pod終止就重啟, 此為default設定。
- OnFailure: Pod發生錯誤時才重啟。
- Never: 從不重啟。

### 基本部署種類
k8s目前簡單的種類有兩種，重建部署策略(Recreate)、滾動部署（Ramped aka. Rolling-update)

// app-v1.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: auth-service-deployment
  labels:
    app: auth-service
spec:
  replicas: 3
  strategy:
    type: RollingUpdate //default
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  selector:
    matchLabels:
      app: auth-service
  template:
    metadata:
      labels:
        app: auth-service
        version: v1
    spec:
      containers:
        - name: auth-service
          image: odinveve/auth-service
          ports:
            - containerPort: 8080

### 由於k8s server API沒有==stop==這個概念，若要關閉了話，直接吧==replicas==設成==0==即可

### 刪除全部
kubectl delete all --all --namespace default

## Minikube
### 啟動dashboard
minikube dashboard

### service為loadBalancer時，要expose去建立外部ＩＰ（測試會需要）
minikube tunnel

### 為service建立通道，並返回一個可造訪的URL
minikube service <service_name> -n <sn>