k8s-----------控制器

目录Deployment(部署无状态应用)Pod与控制器之间的关系SatefulSet（部署有状态应用）无状态和有状态无状态有状态常规service和无头服务区别DaemonSetjobCronJob控制器：又称之为工作负载，分别包含以下类型控制器Deployment(部署无状态应用)Pod与控制器之间的关系controllers：在集群上管理和运行容器的对象通过label-selector相关联

huangzhihuan0813

578人浏览 · 2021-04-20 16:35:38

huangzhihuan0813 · 2021-04-20 16:35:38 发布

Deployment(部署无状态应用)

Pod与控制器之间的关系

controllers：在集群上管理和运行容器的对象通过label-selector相关联
Pod通过控制器实现应用的运维，如伸缩，升级等
管理Pod和ReplicaSet,具有上线部署、副本设定、滚动升级、回滚等功能,提供声明式更新，例如只更新一个新的Image
应用场景：web服务
例子：

[root@localhost demo]# kubectl create -f nginx-deployment.yaml

#Replicaset 是控制版本，副本数，回滚就是通过此来实现
[root@localhost demo]# kubectl get pods,deploy,rs
NAME                                  READY   STATUS    RESTARTS   AGE
pod/nginx-deployment-d55b94fd-9pwvk   1/1     Running   0          45s
pod/nginx-deployment-d55b94fd-dk4sr   1/1     Running   0          45s
pod/nginx-deployment-d55b94fd-ncrbk   1/1     Running   0          45s
pod/pod-example                       1/1     Running   0          39m

NAME                                     DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
deployment.extensions/nginx-deployment   3         3         3            3           45s

NAME                                              DESIRED   CURRENT   READY   AGE
replicaset.extensions/nginx-deployment-d55b94fd   3         3         3       45s

查看控制器
[root@localhost demo]# kubectl edit deployment/nginx-deployment
spec:
  progressDeadlineSeconds: 600
  replicas: 3
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: nginx
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx:1.15.4
        imagePullPolicy: IfNotPresent
  name: nginx-deployment
  namespace: default
  resourceVersion: "880370"
  selfLink: /apis/extensions/v1beta1/namespaces/default/deployments/nginx-deployment
  uid: d5f1ec3d-50cd-11ea-895a-000c297a15fb


查看历史版本
[root@localhost demo]# kubectl rollout history deployment/nginx-deployment
deployment.extensions/nginx-deployment 
REVISION  CHANGE-CAUSE
1         <none>

SatefulSet（部署有状态应用）

解决Pod独立生命周期，保持Pod启动顺序和唯一性，稳定，唯一的网络标识符，持久存储（例如：etcd配置文件，节点地址发生变化，将无法使用），有序，优雅的部署和扩展、删除和终止（例如：mysql主从关系，先启动主，再启动从）有序，滚动更新
应用场景：数据库

无状态和有状态

无状态

deployment 认为所有的pod都是一样的
不用考虑顺序的要求
不用考虑在哪个node节点上运行
可以随意扩容和缩容

有状态

实例之间有差别，每个实例都有自己的独特性，元数据不同，例如etcd，zookeeper
实例之间不对等的关系，以及依靠外部存储的应用。

常规service和无头服务区别

service：一组Pod访问策略，提供cluster-IP群集之间通讯，还提供负载均衡和服务发现。
Headless service 无头服务，不需要cluster-IP，直接绑定具体的Pod的IP
例如：

[root@localhost demo]# kubectl create -f nginx-service.yaml 
service/nginx-service created
[root@localhost demo]# kubectl get svc
NAME            TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.0.0.1     <none>        443/TCP        18d
nginx-service   NodePort    10.0.0.202   <none>        80:32655/TCP   3m17s
//在node节点上操作（注意：coredns地址统一，否则无法解析）
[root@localhost ~]# systemctl restart flanneld.service 
[root@localhost ~]# systemctl restart docker
//查看群集间通讯
[root@localhost ~]# curl 10.0.0.202
<!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>

//headless方式（因为Pod动态IP地址，所以常用于绑定DNS访问）
[root@localhost demo]# vim headless.yaml
apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx

[root@localhost demo]# kubectl apply -f headless.yaml 
service/nginx created
[root@localhost demo]# kubectl get svc
NAME            TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.0.0.1     <none>        443/TCP        19d
nginx           ClusterIP   None         <none>        80/TCP         28s
nginx-service   NodePort    10.0.0.202   <none>        80:32655/TCP   15m

复制coredns.yaml到master01的root家目录

[root@localhost ~]# ls
coredns.yaml 
[root@localhost ~]# kubectl create -f coredns.yaml
serviceaccount/coredns created
clusterrole.rbac.authorization.k8s.io/system:coredns created
clusterrolebinding.rbac.authorization.k8s.io/system:coredns created
configmap/coredns created
deployment.extensions/coredns created
service/kube-dns created
[root@localhost ~]# kubectl get pods -n kube-system
NAME                                    READY   STATUS    RESTARTS   AGE
coredns-56684f94d6-mvrw5                1/1     Running   0          2m15s
kubernetes-dashboard-7dffbccd68-txcmp   1/1     Running   2          9d
[root@localhost ~]# cd demo/
[root@localhost demo]# vim pod3.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: dns-test
spec:
  containers:
  - name: busybox
    image: busybox:1.28.4
    args:
    - /bin/sh
    - -c
    - sleep 36000
  restartPolicy: Never

//验证dns解析
[root@localhost demo]# kubectl create -f pod3.yaml 
pod/dns-test created
[root@localhost demo]# kubectl get svc
NAME            TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes      ClusterIP   10.0.0.1     <none>        443/TCP        19d
nginx           ClusterIP   None         <none>        80/TCP         24m
nginx-service   NodePort    10.0.0.202   <none>        80:32655/TCP   39m
//解析kubernetes和nginx-service名称
[root@localhost demo]# kubectl exec -it dns-test sh
/ # nslookup kubernetes
Server:    10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local

Name:      kubernetes
Address 1: 10.0.0.1 kubernetes.default.svc.cluster.local
/ # nslookup nginx-service
Server:    10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local

Name:      nginx-service
Address 1: 10.0.0.202 nginx-service.default.svc.cluster.local

[root@localhost demo]# vim sts.yaml
apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx
---
apiVersion: apps/v1beta1  
kind: StatefulSet  
metadata:
  name: nginx-statefulset  
  namespace: default
spec:
  serviceName: nginx  
  replicas: 3  
  selector:
    matchLabels:  
       app: nginx
  template:  
    metadata:
      labels:
        app: nginx  
    spec:
      containers:
      - name: nginx
        image: nginx:latest  
        ports:
        - containerPort: 80

清理所有pod

[root@localhost demo]# kubectl delete -f .
[root@localhost demo]# kubectl create -f sts.yaml 
statefulset.apps/nginx-statefulset created
[root@localhost demo]# kubectl get pods
NAME                  READY   STATUS    RESTARTS   AGE
nginx-statefulset-0   1/1     Running   0          30s
nginx-statefulset-1   1/1     Running   0          17s
nginx-statefulset-2   1/1     Running   0          9s

[root@localhost demo]# kubectl get pods,svc
NAME                      READY   STATUS    RESTARTS   AGE
pod/nginx-statefulset-0   1/1     Running   0          4m51s
pod/nginx-statefulset-1   1/1     Running   0          4m38s
pod/nginx-statefulset-2   1/1     Running   0          4m30s

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.0.0.1     <none>        443/TCP   19d
service/nginx        ClusterIP   None         <none>        80/TCP    64s

[root@localhost demo]# kubectl apply -f pod6.yaml 
pod/dns-test created
//解析pod的唯一域名和自身的ip
[root@localhost demo]# kubectl exec -it dns-test sh
/ # nslookup nginx-statefulset-0.nginx
Server:    10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local

Name:      nginx-statefulset-0.nginx
Address 1: 172.17.42.2 nginx-statefulset-0.nginx.default.svc.cluster.local
/ # nslookup nginx-statefulset-1.nginx
Server:    10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local

Name:      nginx-statefulset-1.nginx
Address 1: 172.17.25.2 nginx-statefulset-1.nginx.default.svc.cluster.local
/ # nslookup nginx-statefulset-2.nginx
Server:    10.0.0.2
Address 1: 10.0.0.2 kube-dns.kube-system.svc.cluster.local

Name:      nginx-statefulset-2.nginx
Address 1: 172.17.42.3 nginx-statefulset-2.nginx.default.svc.cluster.local

总结：StatefulSet与Deployment区别：有身份的！身份三要素：域名 nginx-statefulset-0.nginx 主机名 nginx-statefulset-0 存储（PVC）

DaemonSet

在每一个Node上运行一个Pod 新加入的Node也同样会自动运行一个Pod
应用场景：Agent
例如

[root@localhost demo]# vim ds.yaml 

apiVersion: apps/v1
kind: DaemonSet 
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.15.4
        ports:
        - containerPort: 80

[root@localhost demo]# kubectl apply -f ds.yaml 
daemonset.apps/nginx-deployment created
//DaemonSet会在每个node节点都创建一个Pod
[root@localhost demo]# kubectl get pods
nginx-deployment-4kr6h   1/1     Running     0          35s
nginx-deployment-8jrg5   1/1     Running     0          35s

job

Job分为普通任务（Job）和定时任务（CronJob）
一次性执行
应用场景：离线数据处理，视频解码等业务
例如
示例中，重试次数默认是6次，修改为4次，当遇到异常时Never状态会重启，所以要设定次数。

[root@localhost demo]# vim job.yaml
apiVersion: batch/v1
kind: Job
metadata:
  name: pi
spec:
  template:
    spec:
      containers:
      - name: pi
        image: perl
        command: ["perl",  "-Mbignum=bpi", "-wle", "print bpi(2000)"]
      restartPolicy: Never
  backoffLimit: 4

在node节点下载perl镜像，因为镜像比较大所以提前下载好

[root@localhost ~]# docker pull perl

#master
[root@localhost demo]# kubectl apply -f job.yaml 
计算完成状态
[root@localhost demo]# kubectl get pods
pi-bqtf7                 0/1     Completed   0          41s
结果输出到控制台
[root@localhost demo]# kubectl logs pi-bqtf7
3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989380952572010654858632788659361533818279682303019520353018529689957736225994138912497217752834791315155748572424541506959508295331168617278558890750983817546374649393192550604009277016711390098488240128583616035637076601047101819429555961989467678374494482553797747268471040475346462080466842590694912933136770289891521047521620569660240580381501935112533824300355876402474964732639141992726042699227967823547816360093417216412199245863150302861829745557067498385054945885869269956909272107975093029553211653449872027559602364806654991198818347977535663698074265425278625518184175746728909777727938000816470600161452491921732172147723501414419735685481613611573525521334757418494684385233239073941433345477624168625189835694855620992192221842725502542568876717904946016534668049886272327917860857843838279679766814541009538837863609506800642251252051173929848960841284886269456042419652850222106611863067442786220391949450471237137869609563643719172874677646575739624138908658326459958133904780275901

[root@localhost demo]# kubectl get job
NAME   COMPLETIONS   DURATION   AGE
pi     1/1           24s        3m37s
//清除job资源
[root@localhost demo]# kubectl delete -f job.yaml 
job.batch "pi" deleted

CronJob

周期性任务，像Linux的Crontab一样。周期性任务
应用场景：通知，备份
例如：

#每分钟打印hello
[root@localhost ~]# vim cronjob.yaml
apiVersion: batch/v1beta1
kind: CronJob
metadata:
  name: hello
spec:
  schedule: "*/1 * * * *"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
          - name: hello
            image: busybox
            args:
            - /bin/sh
            - -c
            - date; echo Hello from the Kubernetes cluster
          restartPolicy: OnFailure

[root@localhost demo]# kubectl get cronjob
NAME    SCHEDULE      SUSPEND   ACTIVE   LAST SCHEDULE   AGE
hello   */1 * * * *   False     0        <none>          25s
[root@localhost demo]# kubectl get pods
NAME                     READY   STATUS      RESTARTS   AGE
hello-1581917340-dzxbj   0/1     Completed   0          24s
[root@localhost demo]# kubectl logs hello-1581917340-dzxbj
Mon Feb 17 05:29:09 UTC 2020
Hello from the Kubernetes cluster
//等待一分钟后又会再执行一次
[root@localhost demo]# kubectl get pods
hello-1581917340-dzxbj   0/1     Completed   0          2m45s
hello-1581917400-nkb72   0/1     Completed   0          105s

K8S/Kubernetes

K8S/Kubernetes社区为您提供最前沿的新闻资讯和知识内容

更多推荐

【深度】阿里巴巴万级规模 K8s 集群全局高可用体系之美

作者 | 韩堂、柘远、沉醉来源 | 阿里巴巴云原生公众号前言台湾作家林清玄在接受记者采访的时候，如此评价自己 30 多年写作生涯：“第一个十年我才华横溢，‘贼光闪现’，令周边黯然失色；第二个十年，我终于‘宝光现形’，不再去抢风头，反而与身边的美丽相得益彰；进入第三个十年，繁华落尽见真醇，我进入了‘醇光初现’的阶段，真正体味到了境界之美”。长夜有穷，真水无香。领略过了 K8s“身在江

K8S/Kubernetes

如何基于 K8s 构建下一代 DevOps 平台？

作者 | 孙健波（天元）导读：当前云原生 DevOps 体系现状如何？面临哪些挑战？如何通过 OAM 解决云原生 DevOps 场景下的诸多问题？云原生开发应用模型 OAM(Open Application Model) 社区核心成员孙健波将为大家一一解答，并分享如何基于 OAM 和 Kubernetes 打造无限能力的下一代 DevOps 平台。什么是 DevOps？为什么基于 Kub