Service

系统管理员 2022-10-16 07:58 159阅读 0赞

Service定义了一组Pod的访问规则，pod会在service上注册与发现，通过service实现对pod访问的负载均衡，service和pod通过标签关联在一起。Service的类型有三种：clusterIP：默认类型，仅集群内部访问；NodePort：可集群外部访问；loadBalancer：可集群外部访问，可以使用公有云负载均衡器。

### 1 生成资源编排文件 ###

[root@k8smaster ~]# kubectl create deploy nginx --image=nginx -o yaml --dry-run > web.yaml
    W0527 02:56:54.765608   47563 helpers.go:535] --dry-run is deprecated and can be replaced with --dry-run=client.
    [root@k8smaster ~]# ls
    anaconda-ks.cfg  web.yaml
    [root@k8smaster ~]# cat web.yaml
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
      name: nginx
    spec:
      replicas: 1
      selector:
        matchLabels:
          app: nginx
      strategy: {}
      template:
        metadata:
          creationTimestamp: null
          labels:
            app: nginx
        spec:
          containers:
          - image: nginx
            name: nginx
            resources: {}
    status: {}
    [root@k8smaster ~]#

### 2 修改yaml文件设置副本数为2 ###

[root@k8smaster ~]# cat web.yaml
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
      name: nginx
    spec:
      replicas: 2
      selector:
        matchLabels:
          app: nginx
      strategy: {}
      template:
        metadata:
          creationTimestamp: null
          labels:
            app: nginx
        spec:
          containers:
          - image: nginx
            name: nginx
            resources: {}
    status: {}

### 3 运行pod ###

# 运行pod
    [root@k8smaster ~]# kubectl apply -f web.yaml
    deployment.apps/nginx created
    
    # 查看pod 和 服务
    [root@k8smaster ~]# kubectl get pods,svc
    NAME                        READY   STATUS    RESTARTS   AGE
    pod/nginx-f89759699-tgcww   1/1     Running   0          56s
    pod/nginx-f89759699-tqwqg   1/1     Running   0          56s
    
    NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
    service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   15h

### 4 导出服务yaml ###

[root@k8smaster ~]# kubectl expose deploy nginx --port=80 --target-port=80 -o yaml --dry-run >web1.yaml
    W0527 03:18:17.372494   51402 helpers.go:535] --dry-run is deprecated and can be replaced with --dry-run=client.
    [root@k8smaster ~]# ls
    anaconda-ks.cfg  web1.yaml  web.yaml
    [root@k8smaster ~]# cat web1.yaml
    apiVersion: v1
    kind: Service
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
      name: nginx
    spec:
      ports:
      - port: 80
        protocol: TCP
        targetPort: 80
      selector:
        app: nginx
    status:
      loadBalancer: {}

### 5 编辑yaml修改服务名称为web ###

[root@k8smaster ~]# cat web1.yaml
    apiVersion: v1
    kind: Service
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
      name: nginx
    spec:
      ports:
      - port: 80
        protocol: TCP
        targetPort: 80
      selector:
        app: nginx
    status:
      loadBalancer: {}
    [root@k8smaster ~]# vim web1.yaml
    [root@k8smaster ~]# cat web1.yaml
    apiVersion: v1
    kind: Service
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
      name: web
    spec:
      ports:
      - port: 80
        protocol: TCP
        targetPort: 80
      selector:
        app: nginx
    status:
      loadBalancer: {}

### 6 基于资源编排文件创建service ###

# 创建service
    [root@k8smaster ~]# kubectl apply -f web1.yaml
    service/web created
    
    # 查看service
    [root@k8smaster ~]# kubectl get svc
    NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE
    kubernetes   ClusterIP   10.96.0.1      <none>        443/TCP   15h
    web          ClusterIP   10.104.81.18   <none>        80/TCP    98s
    
    # 访问服务ip
    [root@k8snode2 ~]# curl 10.104.81.18
    <!DOCTYPE html>
    <html>
    <head>
    <title>Welcome to nginx!</title>
    <style>
        body {
            width: 35em;
            margin: 0 auto;
            font-family: Tahoma, Verdana, Arial, sans-serif;
        }
    </style>
    </head>
    <body>
    <h1>Welcome to nginx!</h1>
    <p>If you see this page, the nginx web server is successfully installed and
    working. Further configuration is required.</p>
    
    <p>For online documentation and support please refer to
    <a href="http://nginx.org/">nginx.org</a>.<br/>
    Commercial support is available at
    <a href="http://nginx.com/">nginx.com</a>.</p>
    
    <p><em>Thank you for using nginx.</em></p>
    </body>
    </html>

### 7 修改资源编排文件 设置服务类型为 NodePort 启动服务 ###

# 修改资源编排文件 服务名称为web1 类型为NodePort
    [root@k8smaster ~]# cat web1.yaml
    apiVersion: v1
    kind: Service
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
      name: web1
    spec:
      ports:
      - port: 80
        protocol: TCP
        targetPort: 80
      selector:
        app: nginx
      type: NodePort
    status:
      loadBalancer: {}
    
    # 创建服务
    [root@k8smaster ~]# kubectl apply -f web1.yaml
    service/web1 created
    [root@k8smaster ~]# kubectl get svc
    NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
    kubernetes   ClusterIP   10.96.0.1      <none>        443/TCP        16h
    web          ClusterIP   10.104.81.18   <none>        80/TCP         52m
    web1         NodePort    10.99.83.60    <none>        80:31634/TCP   9s

通过web1访问服务，可以在外网用宿主机的ip+暴露的port访问。