使用多节点集群

概述

• 本教程将向您展示如何在 minikube 上启动多节点集群并在其中部署服务。

先决条件

• minikube 1.10.1 或更高版本
• kubectl

注意

默认的 host-path 卷配置器 不支持多节点集群 (#12360)。为了能够在多节点集群中配置或声明卷，您可以使用 CSI Hostpath 驱动程序 插件。

教程

• 在您选择的驱动程序中启动一个包含 2 个节点的集群

minikube start --nodes 2 -p multinode-demo

😄  [multinode-demo] minikube v1.18.1 on Opensuse-Tumbleweed
✨  Automatically selected the docker driver
👍  Starting control plane node multinode-demo in cluster multinode-demo
🔥  Creating docker container (CPUs=2, Memory=8000MB) ...
🐳  Preparing Kubernetes v1.20.2 on Docker 20.10.3 ...
    ▪ Generating certificates and keys ...
    ▪ Booting up control plane ...
    ▪ Configuring RBAC rules ...
🔗  Configuring CNI (Container Networking Interface) ...
🔎  Verifying Kubernetes components...
    ▪ Using image gcr.io/k8s-minikube/storage-provisioner:v5
🌟  Enabled addons: storage-provisioner, default-storageclass

👍  Starting node multinode-demo-m02 in cluster multinode-demo
🔥  Creating docker container (CPUs=2, Memory=8000MB) ...
🌐  Found network options:
    ▪ NO_PROXY=192.168.49.2
🐳  Preparing Kubernetes v1.20.2 on Docker 20.10.3 ...
    ▪ env NO_PROXY=192.168.49.2
🔎  Verifying Kubernetes components...
🏄  Done! kubectl is now configured to use "multinode-demo" cluster and "default" namespace by default

• 获取您的节点列表

kubectl get nodes

NAME                 STATUS   ROLES                  AGE   VERSION
multinode-demo       Ready    control-plane,master   99s   v1.20.2
multinode-demo-m02   Ready    <none>                 73s   v1.20.2

• 您还可以检查您的节点状态

minikube status -p multinode-demo

multinode-demo
type: Control Plane
host: Running
kubelet: Running
apiserver: Running
kubeconfig: Configured

multinode-demo-m02
type: Worker
host: Running
kubelet: Running

• 部署我们的 hello world 部署

kubectl apply -f hello-deployment.yaml

deployment.apps/hello created

kubectl rollout status deployment/hello

deployment "hello" successfully rolled out

• 部署我们的 hello world 服务，该服务仅返回提供请求的 IP 地址

kubectl apply -f hello-svc.yaml

service/hello created

• 查看我们 Pod 的 IP 地址，以供将来参考

kubectl get pods -o wide

NAME                     READY   STATUS    RESTARTS   AGE   IP           NODE                 NOMINATED NODE   READINESS GATES
hello-695c67cf9c-bzrzk   1/1     Running   0          22s   10.244.1.2   multinode-demo-m02   <none>           <none>
hello-695c67cf9c-frcvw   1/1     Running   0          22s   10.244.0.3   multinode-demo       <none>           <none>

• 查看我们的服务，以了解要访问的 URL

minikube service list -p multinode-demo

|-------------|------------|--------------|---------------------------|
|  NAMESPACE  |    NAME    | TARGET PORT  |            URL            |
|-------------|------------|--------------|---------------------------|
| default     | hello      |           80 | http://192.168.49.2:31000 |
| default     | kubernetes | No node port |                           |
| kube-system | kube-dns   | No node port |                           |
|-------------|------------|--------------|---------------------------|

• 让我们多次访问该 URL，看看会返回什么

curl  http://192.168.49.2:31000

Hello from hello-695c67cf9c-frcvw (10.244.0.3)

curl  http://192.168.49.2:31000
Hello from hello-695c67cf9c-bzrzk (10.244.1.2)

curl  http://192.168.49.2:31000
Hello from hello-695c67cf9c-bzrzk (10.244.1.2)

curl  http://192.168.49.2:31000
Hello from hello-695c67cf9c-frcvw (10.244.0.3)

• 多个节点！

• 引用的 YAML 文件

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello
spec:
  replicas: 2
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 100%
  selector:
    matchLabels:
      app: hello
  template:
    metadata:
      labels:
        app: hello
    spec:
      affinity:
        # ⬇⬇⬇ This ensures pods will land on separate hosts
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions: [{ key: app, operator: In, values: [hello] }]
              topologyKey: "kubernetes.io/hostname"
      containers:
        - name: hello-from
          image: pbitty/hello-from:latest
          ports:
            - name: http
              containerPort: 80
      terminationGracePeriodSeconds: 1

apiVersion: v1
kind: Service
metadata:
  name: hello
spec:
  type: NodePort
  selector:
    app: hello
  ports:
    - protocol: TCP
      nodePort: 31000
      port: 80
      targetPort: http