[PHP知识库]k8s部署一个nginx的pod

1 k8s 部署一个nginx的pod

[root@k8s-master1 package]# cat nginx-deployment.yml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:stable
        ports:
        - containerPort: 80


###配置文件解析###
1.apiVersion当前配置格式的版本
2.kind是要创建的资源类型，这里是Deployment
3.metadata是该资源的元数据，name是必须的元数据项
4.spec部分是该Deployment的规格说明
5.replicas指明副本数量，默认为1
6.template定义pod的模块，这是配置文件的重要部分
7.metadata定义pod的元数据，至少要定义一个label，label的key和value可以任意指定
8.spec描述pod的规格，此部分定义pod中每一个容器的属性，name和image是必需的

[root@k8s-master1 package]# cat nginx-service.yml 
kind: Service
apiVersion: v1
metadata:
  name: nginx-service
spec:
  selector:
    app: nginx
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  type: NodePort

2 启动 pod，暴露端口

[root@k8s-master1 package]# kubectl  apply -f nginx-deploymeht.yml 
deployment.apps/nginx-deployment created
[root@k8s-master1 package]# kubectl apply -f nginx-service.yml 
service/nginx-service created

3 查看 pod，查看svc(也叫service)

[root@k8s-master1 package]# kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
busybox                             1/1     Running   22         7d
nginx-deployment-5ff58d798d-r2k8b   1/1     Running   2          8m16s
nginx-deployment-5ff58d798d-zm9fn   1/1     Running   2          8m16s
[root@k8s-master1 package]# kubectl get svc
NAME            TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.0.0.1     <none>        443/TCP        3d21h
nginx-service   NodePort    10.0.0.126   <none>        80:32153/TCP   7m43s

4 查看 nginx-deployment

[root@k8s-master1 ~]# kubectl get deployment 
NAME               READY   UP-TO-DATE   AVAILABLE   AGE
nginx-deployment   2/2     2            2           12m


##如果要删除
kubectl  delete deployment nginx-deployment 或者 kubectl delete -f nginx-deployment.yml


#查看更详细的信息
[root@k8s-master1 ~]# kubectl describe deployment nginx-deployment
Name:                   nginx-deployment
Namespace:              default
CreationTimestamp:      Mon, 06 Sep 2021 15:07:49 +0800
Labels:                 app=nginx
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=nginx
Replicas:               2 desired | 2 updated | 2 total | 2 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  app=nginx
  Containers:
   nginx:
    Image:        nginx:stable
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   nginx-deployment-5ff58d798d (2/2 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  14m   deployment-controller  Scaled up replica set nginx-deployment-5ff58d798d to 2

# 查看replicaset 
[root@k8s-master1 ~]# kubectl get replicaset
NAME                          DESIRED   CURRENT   READY   AGE
nginx-deployment-5ff58d798d   2         2         2       35m
通过信息可以看出创建了一个nginx-deployment-5ff58d798d，也验证了deployment是通过replicaset来管理pod的事实，也可以看出有俩个副本


## 查看详细的信息
[root@k8s-master1 ~]# 
[root@k8s-master1 ~]# kubectl describe replicaset nginx-deployment-5ff58d798d
Name:           nginx-deployment-5ff58d798d
Namespace:      default
Selector:       app=nginx,pod-template-hash=5ff58d798d
Labels:         app=nginx
                pod-template-hash=5ff58d798d
Annotations:    deployment.kubernetes.io/desired-replicas: 2
                deployment.kubernetes.io/max-replicas: 3
                deployment.kubernetes.io/revision: 1
Controlled By:  Deployment/nginx-deployment
Replicas:       2 current / 2 desired
Pods Status:    2 Running / 0 Waiting / 0 Succeeded / 0 Failed
Pod Template:
  Labels:  app=nginx
           pod-template-hash=5ff58d798d
  Containers:
   nginx:
    Image:        nginx:stable
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Events:
  Type    Reason            Age   From                   Message
  ----    ------            ----  ----                   -------
  Normal  SuccessfulCreate  42m   replicaset-controller  Created pod: nginx-deployment-5ff58d798d-zm9fn
  Normal  SuccessfulCreate  42m   replicaset-controller  Created pod: nginx-deployment-5ff58d798d-r2k8b

查看pod
[root@k8s-master1 ~]# kubectl get pods
NAME                                READY   STATUS    RESTARTS   AGE
busybox                             1/1     Running   23         7d
nginx-deployment-5ff58d798d-r2k8b   1/1     Running   2          44m
nginx-deployment-5ff58d798d-zm9fn   1/1     Running   2          44m


#查看pod的详细信息
[root@k8s-master1 ~]# kubectl describe pod  nginx-deployment-5ff58d798d-r2k8b

5 各个组件的协作

1.kubectl发送部署请求到API Server
2.Api Server 通知Controller Manager 创建一个 deployment资源
3.Scheduler执行调度任务，将俩个副本pod发送到k8s-node1和k8s-node2等
4.k8s-node1和k8s-node2上的kubectl在各自的节点上创建并运行pod
补充俩点：
应用的配置和当前状态信息保存在etcd中，执行kubectl get pod时，Api Server 会从etcd中读取这些数据
flannel会为每个pod都分配IP，因为没有创建service，所以目前kube-proxy还没参与进来

6 k8s部署nginx的pod过程

k8s部署pod过程
用户通过kubectl创建deployment
deployment创建replicaset
replicaset创建pod