Kubernetes：在现有集群中启动单个容器，用于运行 cron 作业

Question

我正在开发 Kubernetes 集群，我想在其中运行一个运行 cron 作业的容器。在同一个集群中，我正在部署 3 个其他容器，它们运行 app-code。在同一个集群中添加不同类型的容器需要哪些更改？

service.yaml：

apiVersion: v1
kind: Service
metadata:
  labels:
    app.kubernetes.io/name: supplier-service
    app.kubernetes.io/instance: supplier-service-instance
    app.kubernetes.io/version: "1.0.0"
    app.kubernetes.io/component: backend
    app.kubernetes.io/managed-by: kubectl
  annotations:
      # Note that the backend talks over HTTP.
    service.beta.kubernetes.io/aws-load-balancer-backend-protocol: tcp
       # TODO: Fill in with the ARN of your certificate.
    service.beta.kubernetes.io/aws-load-balancer-ssl-cert: OUR_ARN
       # Only run SSL on the port named "https" below.
    service.beta.kubernetes.io/aws-load-balancer-ssl-ports: https
    service.beta.kubernetes.io/do-loadbalancer-redirect-http-to-https: "true"
    service.beta.kubernetes.io/do-loadbalancer-tls-ports: "443"
  name: supplier-service

spec:
  selector:
    app: supplier-service
  type: LoadBalancer
  ports:
  - name: http
    port: 80
    targetPort: 80
  - name: https
    port: 443
    targetPort: 443

deployment.yaml -- 这个 Yaml 文件运行 app-code

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    app.kubernetes.io/name: supplier-service
    app.kubernetes.io/instance: supplier-service-instance
    app.kubernetes.io/version: '1.0.0'
    app.kubernetes.io/managed-by: kubectl
  name: supplier-service-deployment
spec:
  replicas: 3
  strategy:
     type: RollingUpdate
     rollingUpdate:
        maxUnavailable: 25%
        maxSurge: 1
  selector:
    matchLabels: 
      app: supplier-service
  template: 
    metadata:
      labels: 
        app: supplier-service
    spec:
      containers:
        - image: IMAGE-FROM-ECR/supplier-service:latest
          imagePullPolicy: Always
          name: supplier-service
          ports: 
            - containerPort: 80
            - containerPort: 443
            - containerPort: 6379

我准备好了一个新的 DockerFile，它可以在容器内安装 cron 作业。

部署-cron.yaml：

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    app.kubernetes.io/name: supplier-service
    app.kubernetes.io/instance: supplier-service-instance
    app.kubernetes.io/version: '1.0.0'
    app.kubernetes.io/managed-by: kubectl
  name: supplier-service-deployment
spec:
  replicas: 1
  strategy:
     type: RollingUpdate
     rollingUpdate:
        maxUnavailable: 25%
        maxSurge: 1
  selector:
    matchLabels: 
      app: supplier-service
  template: 
    metadata:
      labels: 
        app: supplier-service
    spec:
      containers:
        - image: AWS-ECR/supplier-service-cron:latest
          imagePullPolicy: Always
          name: supplier-service
          ports: 
            - containerPort: 80
            - containerPort: 443
            - containerPort: 6379

这是在现有集群中运行单个容器的正确方法，还是需要进行任何其他更改？谢谢你。 :-)

Answer 1

当您尝试在同一命名空间中部署两个具有相同名称的部署时，上述方法会向您抛出错误。

您正在尝试做的示例如下

$ cat deploy1.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    deployment1: One
  name: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      deployment1: One
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        deployment1: One
    spec:
      containers:
      - image: nginx
        name: nginx
        resources: {}
status: {}

$ cat deploy2.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    deployment2: Two
  name: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      deployment2: Two
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        deployment2: Two
    spec:
      containers:
      - image: nginx
        name: nginx
        resources: {}
status: {}

创建第一个部署。

$ kubectl create -f deploy1.yaml
deployment.apps/nginx created

在同一个命名空间中创建第二个，你应该会看到这个错误。

$ kubectl create -f deploy2.yaml
Error from server (AlreadyExists): error when creating "deploy2.yaml": deployments.apps "nginx" already exists

Answer 2

命名和标签需要从原始部署 yaml 更改。

如果您保持metadata.name 不变，您将修改kubectl apply -f 上的现有部署，而不是创建新部署。

如果您的所有运行都是 cron，我认为您不需要这些端口，除非它正在运行 supplier-service 的完整实例

如果您将标签 app: supplier-service 留在您的 cron 容器上，现有的 Service 选择器会变得混乱。

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    app.kubernetes.io/name: supplier-service
    app.kubernetes.io/instance: supplier-service-instance
    app.kubernetes.io/version: '1.0.0'
    app.kubernetes.io/managed-by: kubectl
  name: supplier-service-cron-deployment
spec:
  replicas: 1
  selector:
    matchLabels: 
      app: supplier-service-cron
  template: 
    metadata:
      labels: 
        app: supplier-service-cron
    spec:
      containers:
        - image: AWS-ECR/supplier-service-cron:latest
          imagePullPolicy: Always
          name: supplier-service-cron

kubernetes 还提供了一个独立的cronjob 功能，以防您不知道。