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

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

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>