kubernetes—五个概念入门（二）-阿里云开发者社区

kubernetes—五个概念入门（一）：https://developer.aliyun.com/article/1417667

Deployment

介绍

在kubernetes中，Pod是最小的控制单元，但是kubernetes很少直接控制Pod，一般都是通过Pod控制器来完成的。Pod控制器用于pod的管理，确保pod资源符合预期的状态，当pod的资源出现故障时，会尝试进行重启或重建pod。

在kubernetes中Pod控制器的种类有很多，本章节只介绍一种：Deployment，别的Pod控制器预计在下下篇博文进行详细介绍。Deployment和pod关系的建立是通过标签label进行建立的，如下图：

操作

命令操作

# 创建deployment
# 命令格式: kubectl create deployment 名称 [参数] 
# --image  指定pod的镜像
# --port   指定端口
# --replicas  指定创建pod数量
# --namespace  指定namespace
[root@master k8sYamlForCSDN]# kubectl create deployment deploy-nginx --image=nginx --port=80 --replicas=3 --namespace=dev
deployment.apps/deploy-nginx created
# 查看创建的Pod
```bash
[root@master k8sYamlForCSDN]# kubectl get pods -n dev
NAME                           READY   STATUS    RESTARTS   AGE
deploy-nginx-fb669cc4f-5xd5j   1/1     Running   0          3m32s
deploy-nginx-fb669cc4f-69pln   1/1     Running   0          3m32s
deploy-nginx-fb669cc4f-tpfhp   1/1     Running   0          3m32s
# 查看deployment的信息
[root@master k8sYamlForCSDN]# kubectl get deployment -n dev
NAME           READY   UP-TO-DATE   AVAILABLE   AGE
deploy-nginx   3/3     3            3           4m21s
# UP-TO-DATE：成功升级的副本数量
# AVAILABLE：可用副本的数量
# 查看deployment和pod的详细信息
[root@master k8sYamlForCSDN]# kubectl get deployment,pods -n dev --show-labels 
NAME                           READY   UP-TO-DATE   AVAILABLE   AGE     LABELS
deployment.apps/deploy-nginx   3/3     3            3           5m42s   app=deploy-nginx
NAME                               READY   STATUS    RESTARTS   AGE     LABELS
pod/deploy-nginx-fb669cc4f-5xd5j   1/1     Running   0          5m42s   app=deploy-nginx,pod-template-hash=fb669cc4f
pod/deploy-nginx-fb669cc4f-69pln   1/1     Running   0          5m42s   app=deploy-nginx,pod-template-hash=fb669cc4f
pod/deploy-nginx-fb669cc4f-tpfhp   1/1     Running   0          5m42s   app=deploy-nginx,pod-template-hash=fb669cc4f
[root@master k8sYamlForCSDN]# kubectl get deployment -n dev -o wide
NAME           READY   UP-TO-DATE   AVAILABLE   AGE     CONTAINERS   IMAGES   SELECTOR
deploy-nginx   3/3     3            3           5m58s   nginx        nginx    app=deploy-nginx

# 查看deployment的详细信息
[root@master k8sYamlForCSDN]# kubectl describe deployment -n dev 
Name:                   deploy-nginx
Namespace:              dev
CreationTimestamp:      Mon, 28 Feb 2022 21:10:32 +0800
Labels:                 app=deploy-nginx
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=deploy-nginx
Replicas:               3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  app=deploy-nginx
  Containers:
   nginx:
    Image:        nginx
    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:   deploy-nginx-fb669cc4f (3/3 replicas created)
Events:
  Type    Reason             Age    From                   Message
  ----    ------             ----   ----                   -------
  Normal  ScalingReplicaSet  6m29s  deployment-controller  Scaled up replica set deploy-nginx-fb669cc4f to 3

# # 删除deployment Pod控制器,删除了pod对应的deployment，则pod也会被删除
[root@master k8sYamlForCSDN]# kubectl delete deployments.apps deploy-nginx -n dev
deployment.apps "deploy-nginx" deleted
[root@master k8sYamlForCSDN]# kubectl get deployment,pods -n dev 
No resources found in dev namespace.

配置操作

# 创建一个deploy-nginx.yaml
vi deploy-nginx.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: deploy-nginx
  namespace: dev
spec:
  replicas: 3
  selector:
    matchLabels:
      run: "nginx"
  template:
    metadata:
      labels:
        run: "nginx"
    spec:
      containers:
        - name: pod
          image: nginx
          ports:
            - containerPort: 80
              protocol: TCP

# 创建
[root@master k8sYamlForCSDN]# kubectl apply -f deploy-nginx.yaml 
deployment.apps/deploy-nginx created
# 查看
[root@master k8sYamlForCSDN]# kubectl get deployments.apps -n dev
NAME           READY   UP-TO-DATE   AVAILABLE   AGE
deploy-nginx   0/3     3            0           11s
[root@master k8sYamlForCSDN]# kubectl get deployments.apps,pods -n dev
NAME                           READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/deploy-nginx   0/3     3            0           15s
NAME                                READY   STATUS              RESTARTS   AGE
pod/deploy-nginx-579f68df74-pn2c8   0/1     ContainerCreating   0          15s
pod/deploy-nginx-579f68df74-sv9nz   0/1     ContainerCreating   0          15s
pod/deploy-nginx-579f68df74-wpndc   0/1     ContainerCreating   0          15s
# 删除
[root@master k8sYamlForCSDN]# kubectl delete -f deploy-nginx.yaml 
deployment.apps "deploy-nginx" deleted

Service

介绍

目前已经能够利用Deployment来创建一组Pod来提供具有高可用性的服务。

虽然每个Pod都会分配一个单独的Pod IP，然而却存在如下两问题：

Pod IP 会随着Pod的重建产生变化
Pod IP 仅仅是集群内可见的虚拟IP，外部无法访问

这样对于访问这个服务带来了难度。因此，kubernetes设计了Service来解决这个问题。

Service可以看作是一组同类Pod对外的访问接口。借助Service，应用可以方便地实现服务发现和负载均衡。

操作

操作一：创建集群内部可访问的Service

这里先简单介绍一下–type=ClusterIP，意思是只有集群内部ip可以访问这个service

# 暴露Service
[root@master k8sYamlForCSDN]# kubectl expose deployment deploy-nginx -n dev \
--name=svc-deploy-nginx --type=ClusterIP --port=80 --target-port=80 
service/svc-deploy-nginx exposed
# 查看service
[root@master k8sYamlForCSDN]# kubectl get service svc-deploy-nginx -n dev -o wide
NAME               TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE   SELECTOR
svc-deploy-nginx   ClusterIP   10.99.101.216   <none>        80/TCP    47s   run=nginx
# 这里产生了一个CLUSTER-IP，这就是service的IP，在Service的生命周期中，这个地址是不会变动的
# 可以通过这个IP访问当前service对应的POD
[root@master k8sYamlForCSDN]# curl 10.99.101.216:80
<!DOCTYPE html>
  ...
  ...
</html>

操作二：创建集群外部也可访问的Service

# 上面创建的Service的type类型为ClusterIP，这个ip地址只用集群内部可访问
# 如果需要创建外部也可以访问的Service，需要修改type为NodePort
[root@master k8sYamlForCSDN]# kubectl expose deployment deploy-nginx -n dev \
> --name=svc-deploy-nginx --type=NodePort --port=80 --target-port=80
service/svc-deploy-nginx exposed
# # 此时查看，会发现出现了NodePort类型的Service，而且有一对Port（80:31928/TC）
[root@master k8sYamlForCSDN]# kubectl get service svc-deploy-nginx -n dev -o wide
NAME               TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE   SELECTOR
svc-deploy-nginx   NodePort   10.99.149.210   <none>        80:30945/TCP   10s   run=nginx
# 接下来就可以通过集群外的主机访问 节点IP:30945访问服务了
# 例如在的电脑主机上通过浏览器访问下面的地址
http://192.168.109.100:30945/

删除Service

[root@master k8sYamlForCSDN]# kubectl delete svc svc-deploy-nginx -n dev
service "svc-deploy-nginx" deleted

配置方式

不论是ClusterIP还是NodePort，yaml文件中的clusterIP: 10.109.68.72可以不配，不配置就是自动分配

# 创建一个svc-nginx.yaml
vi svc-deploy-nginx.yaml

apiVersion: v1
kind: Service
metadata:
  name: svc-deploy-nginx
  namespace: dev
spec:
  type: ClusterIP
  clusterIP: 10.109.68.72
  selector:
    run: "nginx"
  ports:
    - port: 80
      targetPort: 80
      protocol: TCP

[root@master k8sYamlForCSDN]# kubectl apply -f svc-deploy-nginx.yaml 
service/svc-deploy-nginx created
[root@master k8sYamlForCSDN]# kubectl get service svc-deploy-nginx -n dev -o wide
NAME               TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE   SELECTOR
svc-deploy-nginx   ClusterIP   10.109.68.72   <none>        80/TCP    10s   run=nginx
[root@master k8sYamlForCSDN]# kubectl delete -f svc-deploy-nginx.yaml 
service "svc-deploy-nginx" deleted

apiVersion: v1
kind: Service
metadata:
  name: svc-deploy-nginx
  namespace: dev
spec:
  type: NodePort
  clusterIP: 10.109.68.72
  selector:
    run: "nginx"
  ports:
    - port: 6872
      targetPort: 80
      protocol: TCP

apiVersion: v1
kind: Service
metadata:
  name: svc-deploy-nginx
  namespace: dev
spec:
  type: NodePort
  clusterIP: 10.109.68.72
  selector:
    run: "nginx"
  ports:
    - port: 6872
      targetPort: 80
      protocol: TCP

[root@master k8sYamlForCSDN]# kubectl apply -f svc-deploy-nginx.yaml 
service/svc-deploy-nginx created
[root@master k8sYamlForCSDN]# kubectl get service svc-deploy-nginx -n dev -o wide
NAME               TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE   SELECTOR
svc-deploy-nginx   NodePort   10.105.26.121   <none>        6872:31758/TCP   4s    run=nginx
[root@master k8sYamlForCSDN]# kubectl delete -f svc-deploy-nginx.yaml 
service "svc-deploy-nginx" deleted

kubernetes—五个概念入门（二）

Deployment

介绍

操作

Service

介绍

操作

热门文章

最新文章

相关课程

相关电子书

相关实验场景

推荐镜像