Kubernetes

资源文件模板获取

#获取Pod模板：kubectl run mypod --image=nginx --dry-run=client -o yaml

#获取deployment模板：kubectl create deployment myweb --image=myos：httpd --dry-run=client -o yaml

#获取HPA模板（必须有deployment控制器）

kubectl autoscale deployment myweb --min=1 --max=3 --cpu-present=50 --dry-run=client -o yaml

控制器

控制器是什么

控制器是K8S内置的管理工具，可以帮助用户实现Pod的自动部署、自动维护、扩容、滚动更新等功能的自动化程序

Deployment控制器

资源对象案例
[root@master ~]# vim mydeploy.yaml
---
kind: Deployment	#资源对象类型
apiVersion: apps/v1	#版本
metadata:	#元数据
  name: myweb	#名称
spec:	#详细定义
  replicas: 2	#副本数量
  selector:	    #定义标签选择器
    matchLabels:  #同样支持matchExpression表达式语法
      app: myhttp	#ReplicaSet通过标签来确定哪个Pod由它来管理
  template:	#定义用来创建Pod的模板
    metadata:	#Pod元数据
      labels:	#名称由控制器生成
        app: myhttp	#定义标签
    spec:	#Pod的详细定义
      restartPolicy: Always	#重启策略
      containers:	#容器定义
      - name: apache	#容器名称
        image: myos:httpd	#创建容器使用的镜像
        ports:	#容器内服务使用的端口号
        - name:	#端口名称
          protocol: TCP	 #协议
          containerPort: 80	#端口

[root@master ~]# kubectl apply -f mydeploy.yaml 
deployment.apps/myweb created
[root@master ~]# kubectl get deployments.apps 
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
myweb   2/2     2            2           68s
[root@master ~]# kubectl get replicasets.apps 
NAME               DESIRED   CURRENT   READY   AGE
myweb-64b544dcbc   2         2         2       73s
[root@master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
myweb-64b544dcbc-5mhqn   1/1     Running   0          76s
myweb-64b544dcbc-nt6tz   1/1     Running   0          76s

# 创建服务访问集群
[root@master ~]# vim websvc.yaml
---
kind: Service
apiVersion: v1
metadata:
  name: websvc
spec:
  type: ClusterIP
  clusterIP: 10.245.1.80
  selector:
    app: myhttp
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80

[root@master ~]# kubectl apply -f websvc.yaml 
service/websvc created
[root@master ~]# curl -m 3 http://10.245.1.80
Welcome to The Apache.

# 自维护自治理
[root@master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
myweb-64b544dcbc-5mhqn   1/1     Running   0          4m16s
myweb-64b544dcbc-nt6tz   1/1     Running   0          4m16s

# Pod 被删除后，Deploy 会自动创建新的 Pod 来维护集群的完整性
[root@master ~]# kubectl delete pod myweb-64b544dcbc-5mhqn 
pod "myweb-64b544dcbc-5mhqn" deleted
[root@master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
myweb-64b544dcbc-g8l9p   1/1     Running   0          3s
myweb-64b544dcbc-nt6tz   1/1     Running   0          4m25s

# 动态更新集群副本数量
[root@master ~]# kubectl scale deployment myweb --replicas=1
deployment.apps/myweb scaled
[root@master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
myweb-64b544dcbc-nt6tz   1/1     Running   0          5m46s
[root@master ~]# kubectl scale deployment myweb --replicas=3
deployment.apps/myweb scaled
[root@master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
myweb-64b544dcbc-5sf5z   1/1     Running   0          3s
myweb-64b544dcbc-6r6dw   1/1     Running   0          3s
myweb-64b544dcbc-nt6tz   1/1     Running   0          5m56s
历史版本、滚动更新

# 添加注释信息
[root@master ~]# kubectl annotate deployments.apps myweb kubernetes.io/change-cause="httpd.v1"
deployment.apps/myweb annotated

# 修改镜像，滚动更新集群
[root@master ~]# curl -m 3 http://10.245.1.80
Welcome to The Apache.
[root@master ~]# sed 's,\(image: \).*,\1myos:nginx,' mydeploy.yaml |kubectl apply -f -
deployment.apps/myweb configured
# 更新注释信息
[root@master ~]# kubectl annotate deployments.apps myweb kubernetes.io/change-cause="nginx.v1"
deployment.apps/myweb annotated
[root@master ~]# kubectl get replicasets.apps 
NAME               DESIRED   CURRENT   READY   AGE
myweb-5bfdc888d7   2         2         2       3m46s
myweb-64b544dcbc   0         0         0       12m
[root@master ~]# curl -m 3 http://10.245.1.80
Nginx is running !

# 历史版本与回滚
[root@master ~]# kubectl rollout history deployment myweb 
deployment.apps/myweb 
REVISION  CHANGE-CAUSE
1         httpd.v1
2         nginx.v1

[root@master ~]# kubectl rollout undo deployment myweb --to-revision=1
deployment.apps/myweb rolled back
[root@master ~]# kubectl rollout history deployment myweb 
deployment.apps/myweb 
REVISION  CHANGE-CAUSE
2         nginx.v1
3         httpd.v1
[root@master ~]# curl -m 3 http://10.245.1.80
Welcome to The Apache.

# 删除控制器方法1
[root@master ~]# kubectl delete deployments.apps myweb 
deployment.apps "myweb" deleted
# 删除控制器方法2
[root@master ~]# kubectl delete -f mydeploy.yaml
deployment.apps "myweb" deleted

DaemonSet控制器

资源对象案例
[root@master ~]# vim myds.yaml
---
kind: DaemonSet
apiVersion: apps/v1
metadata:
  name: myds
spec:
  selector:
    matchLabels:
      app: myhttp
  template:
    metadata:
      labels:
        app: myhttp
    spec:
      restartPolicy: Always
      containers:
      - name: apache
        image: myos:httpd
        ports:
        - name:
          protocol: TCP
          containerPort: 80

[root@master ~]# kubectl apply -f myds.yaml 
daemonset.apps/myds created
[root@master ~]# kubectl get pods -o wide
NAME         READY   STATUS    RESTARTS   AGE   IP            NODE
myds-4wt72   1/1     Running   0          31s   10.244.3.14   node-0003
myds-lwq8l   1/1     Running   0          31s   10.244.2.17   node-0002
myds-msrcx   1/1     Running   0          31s   10.244.1.11   node-0001

# 删除DS控制器
[root@master ~]# kubectl delete -f myds.yaml 
daemonset.apps "myds" deleted

Job/CronJob控制器

资源对象案例
[root@master ~]# vim myjob.yaml 
---
kind: Job
apiVersion: batch/v1
metadata:
  name: myjob
spec:
  template:
    spec:
      restartPolicy: OnFailure #重启策略只支持OnFailure、Never
      containers:
      - name: myjob
        image: myos:latest
        command: ["/bin/sleep", "30"]

[root@master ~]# kubectl apply -f myjob.yaml 
job.batch/myjob created
[root@master ~]# kubectl get jobs.batch 
NAME    COMPLETIONS   DURATION   AGE
myjob   0/1           3s         3s
[root@master ~]# kubectl get pods -l job-name=myjob
NAME             READY   STATUS    RESTARTS   AGE
myjob--1-kz8mk   1/1     Running   0          6s
[root@master ~]# sleep 30
[root@master ~]# kubectl get pods -l job-name=myjob
NAME             READY   STATUS      RESTARTS   AGE
myjob--1-kz8mk   0/1     Completed   0          58s
[root@master ~]# kubectl get jobs.batch 
NAME    COMPLETIONS   DURATION   AGE
myjob   1/1           31s        64s

# 删除Job控制器
[root@master ~]# kubectl delete -f myjob.yaml 
job.batch "myjob" deleted

资源对象案例
[root@master ~]# vim mycj.yaml
---
kind: CronJob
apiVersion: batch/v1
metadata:
  name: mycronjob
spec:
  schedule: "*/1 * * * 1-5"
  jobTemplate:
    spec:
      template:
        spec:
          restartPolicy: OnFailure
          containers:
          - name: myjob
            image: myos:latest
            command: ["/bin/sleep", "30"]

[root@master ~]# kubectl apply -f mycj.yaml 
cronjob.batch/mycronjob created
[root@master ~]# kubectl get cronjobs.batch 
NAME        SCHEDULE        SUSPEND   ACTIVE   LAST SCHEDULE   AGE
mycronjob   */1 * * * 1-5   False     0        <none>          4s
[root@master ~]# kubectl get jobs.batch 
No resources found in default namespace.
[root@master ~]# kubectl get pods
No resources found in default namespace.
[root@master ~]# sleep 60
[root@master ~]# kubectl get jobs.batch 
NAME                 COMPLETIONS   DURATION   AGE
mycronjob-27605367   0/1           0s         0s
[root@master ~]# kubectl get pods
NAME                          READY   STATUS    RESTARTS   AGE
mycronjob-27605367--1-ps6r8   1/1     Running   0          3s
[root@master ~]# kubectl get jobs.batch 
NAME                 COMPLETIONS   DURATION   AGE
mycronjob-27605367   0/1           12s        12s
[root@master ~]# sleep 200

# 保留三次结果，多余的会被删除
[root@master ~]# kubectl get jobs.batch 
NAME                 COMPLETIONS   DURATION   AGE
mycronjob-27605367   1/1           31s        3m30s
mycronjob-27605368   1/1           31s        2m30s
mycronjob-27605369   1/1           31s        90s
mycronjob-27605370   0/1           30s        30s
[root@master ~]# kubectl get jobs.batch 
NAME                 COMPLETIONS   DURATION   AGE
mycronjob-27605368   1/1           31s        2m33s
mycronjob-27605369   1/1           31s        93s
mycronjob-27605370   1/1           31s        33s

# 删除CJ控制器
[root@master ~]# kubectl delete -f mycj.yaml 
cronjob.batch "mycronjob" deleted

高级控制器

StatefulSet控制器

资源对象案例
# 配置headless服务
[root@master ~]# vim mysvc.yaml 
---
kind: Service
apiVersion: v1
metadata:
  name: mysvc
spec:
  type: ClusterIP
  clusterIP: None
  selector:
    app: myhttp
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80

[root@master ~]# kubectl apply -f mysvc.yaml 
service/mysvc created
[root@master ~]# kubectl get service
NAME         TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)   AGE
mysvc        ClusterIP   None          <none>        80/TCP    61s

# 创建statefulset控制器
[root@master ~]# vim mysts.yaml
---
kind: StatefulSet
apiVersion: apps/v1
metadata:
  name: mysts
spec:
  serviceName: "mysvc"
  selector:
    matchExpressions:
    - key: app
      operator: In
      values:
      - myhttp
  replicas: 3
  template:
    metadata:
      labels:
        app: myhttp
    spec:
      restartPolicy: Always
      containers:
      - name: apache
        image: myos:httpd
        imagePullPolicy: Always
        ports:
        - protocol: TCP
          containerPort: 80

[root@master ~]# kubectl apply -f mysts.yaml 
statefulset.apps/mysts created
[root@master ~]# kubectl get pods
NAME      READY   STATUS    RESTARTS   AGE
mysts-0   1/1     Running   0          4s
mysts-1   1/1     Running   0          3s
mysts-2   1/1     Running   0          2s

[root@master ~]# host mysts-0.mysvc.default.svc.cluster.local 10.245.0.10
Using domain server:
Name: 10.245.0.10
Address: 10.245.0.10#53
Aliases: 

mysts-0.mysvc.default.svc.cluster.local has address 10.244.3.81
[root@master ~]# host mysvc.default.svc.cluster.local 10.245.0.10
Using domain server:
Name: 10.245.0.10
Address: 10.245.0.10#53
Aliases: 

mysvc.default.svc.cluster.local has address 10.244.2.10
mysvc.default.svc.cluster.local has address 10.244.1.12
mysvc.default.svc.cluster.local has address 10.244.3.11

[root@master ~]# curl -m 3 http://10.244.2.10/info.php
<pre>
Array
(
    [REMOTE_ADDR] => 10.244.0.0
    [REQUEST_METHOD] => GET
    [HTTP_USER_AGENT] => curl/7.29.0
    [REQUEST_URI] => /info.php
)
php_host:       mysts-2
1229

# 删除sts控制器
[root@master ~]# kubectl delete -f mysts.yaml -f mysvc.yaml 
statefulset.apps "mysts" deleted
service "mysvc" deleted

HPA控制器

资源对象案例
# 为 Deploy 模板添加资源配额
[root@master ~]# vim mydeploy.yaml 
---
kind: Deployment
apiVersion: apps/v1
metadata:
  name: myweb
spec:
  replicas: 1
  selector:
    matchLabels:
      app: myhttp
  template:
    metadata:
      labels:
        app: myhttp
    spec:
      restartPolicy: Always
      containers:
      - name: apache
        image: myos:httpd
        ports:
        - name:
          protocol: TCP
          containerPort: 80
        resources:
          requests:
            cpu: "200m"

---
kind: Service
apiVersion: v1
metadata:
  name: websvc
spec:
  type: ClusterIP
  clusterIP: 10.245.1.80
  selector:
    app: myhttp
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80

# 使用 Deploy 和 Cluster IP 创建集群
[root@master ~]# kubectl apply -f mydeploy.yaml
deployment.apps/myweb created
service/websvc created
[root@master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
myweb-5946bb4c68-c8tm2   1/1     Running   0          2m43s
[root@master ~]# curl -s http://10.245.1.80
Welcome to The Apache.

# 创建 HPA 控制器
[root@master ~]# vim myhpa.yaml 
---
kind: HorizontalPodAutoscaler
apiVersion: autoscaling/v1
metadata:
  name: myweb
spec:
  minReplicas: 1
  maxReplicas: 3
  scaleTargetRef:
    kind: Deployment
    apiVersion: apps/v1
    name: myweb
  targetCPUUtilizationPercentage: 50

[root@master ~]# kubectl apply -f myhpa.yaml 
horizontalpodautoscaler.autoscaling/myweb created

# 刚刚创建 unknown 是正常现象，最多等待 300s 就可以正常获取数据
[root@master ~]# kubectl get horizontalpodautoscalers.autoscaling 
NAME    REFERENCE          TARGETS         MINPODS   MAXPODS   REPLICAS   AGE
myweb   Deployment/myweb   <unknown>/50%   1         3         0          4s

[root@master ~]# kubectl get horizontalpodautoscalers.autoscaling 
NAME    REFERENCE          TARGETS         MINPODS   MAXPODS   REPLICAS   AGE
myweb   Deployment/myweb   0%/50%          1         3         1          71s
扩容测试

# 终端 1 访问提高负载
[root@master ~]# while true;do
    curl -s "http://10.245.1.80/info.php?id=50000"
    sleep 1
done
# 终端 2 监控 HPA 变化
[root@master ~]# kubectl get hpa -w
NAME    REFERENCE          TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
myweb   Deployment/myweb   0%/50%    1         3         1          8m21s
myweb   Deployment/myweb   49%/50%   1         3         1          9m
myweb   Deployment/myweb   56%/50%   1         3         1          9m15s
myweb   Deployment/myweb   56%/50%   1         3         2          9m30s
myweb   Deployment/myweb   37%/50%   1         3         2          9m45s
myweb   Deployment/myweb   32%/50%   1         3         2          10m
myweb   Deployment/myweb   41%/50%   1         3         2          11m
myweb   Deployment/myweb   48%/50%   1         3         2          11m
myweb   Deployment/myweb   51%/50%   1         3         2          11m
myweb   Deployment/myweb   59%/50%   1         3         2          11m
myweb   Deployment/myweb   58%/50%   1         3         3          12m
myweb   Deployment/myweb   42%/50%   1         3         3          12m
myweb   Deployment/myweb   34%/50%   1         3         3          12m

# 如果 300s 内平均负载小于标准值，就会自动缩减集群规模
[root@master ~]# kubectl get hpa -w
NAME    REFERENCE          TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
myweb   Deployment/myweb   38%/50%   1         3         3          19m
myweb   Deployment/myweb   21%/50%   1         3         3          20m
myweb   Deployment/myweb   17%/50%   1         3         3          21m
myweb   Deployment/myweb    7%/50%   1         3         3          22m
myweb   Deployment/myweb    0%/50%   1         3         3          23m
myweb   Deployment/myweb    0%/50%   1         3         2          25m
myweb   Deployment/myweb    0%/50%   1         3         1          28m
[root@master ~]# kubectl get horizontalpodautoscalers.autoscaling 
NAME    REFERENCE          TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
myweb   Deployment/myweb   0%/50%    1         3         1          5m41s
[root@master ~]# kubectl get pods
NAME                       READY     STATUS    RESTARTS  AGE
myweb-5946bb4c68-f9tw9     1/1       Running   0         6m40s