kubernetes之有状态应用StatefulSet-白红宇

kubernetes之有状态应用StatefulSet

阅读量：5366 次

发布时间：2019-06-15

本文共 11986 字，大约阅读时间需要 39 分钟。

statefulSet

1.稳定且唯一的网络标识符

2.稳定且持久的存储

3.有序,平滑地部署和扩展

4.有序,平滑地删除和终止

5.有序地滚动更新

三个组件:headless service StatefulSet volumeClaimTemplate

headless service:Headless Service也是一种Service，但不同的是会定义spec:clusterIP: None，也就是不需要Cluster IP的Service,因为没有ClusterIP，kube-proxy 并不处理此类服务，因为没有load balancing或 proxy 代理设置，在访问服务的时候会返回后端的全部的Pods IP地址，主要用于开发者自己根据pods进行负载均衡器的开发(设置了selector) 或 StatefulSet

关于headless service的介绍请查看

准备工作

如何创建

在创建StatefulSet之前需要准备的东西，值得注意的是创建顺序非常关键，创建顺序如下：

1、Volume

2、Persistent Volume

3、Persistent Volume Claim

4、Service

5、StatefulSet

1)准备pv,这里我们使用以前创建的pv

https://www.cnblogs.com/linyouyi/articles/10604818.html

[root@master ~]# kubectl get pvNAME    CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGEpv001   5Gi        RWO,RWX        Retain           Available                                   4spv002   5Gi        RWO,RWX        Retain           Available                                   4spv003   5Gi        RWO,RWX        Retain           Available                                   4spv004   5Gi        RWO,RWX        Retain           Available                                   4spv005   5Gi        RWO,RWX        Retain           Available                                   4s

创建Service,statefulset

[root@master ~]# vim myapp-statefulset.yaml apiVersion: v1kind: Servicemetadata:  name: myappservice  labels:    app: statefulsetspec:  ports:  - port: 80    name: web  clusterIP: None  selector:    app: myapp-pod---apiVersion: apps/v1kind: StatefulSetmetadata:  name: myappspec:  serviceName: myappservice        //要和上面的myappservice一样  replicas: 3  selector:    matchLabels:      app: myapp-pod  template:    metadata:      labels:        app: myapp-pod    spec:      containers:      - name: myapp        image: ikubernetes/myapp:v1        ports:        - containerPort: 80          name: web        volumeMounts:        - name: myappdata          mountPath: /usr/share/nginx/html  volumeClaimTemplates:  - metadata:      name: myappdata    spec:      accessModes: ["ReadWriteOnce"]    //此处要确保你已经有足够的pv,且模式含ReadWriteOnce      resources:        requests:          storage: 1Gi[root@master ~]# kubectl apply -f myapp-statefulset.yaml service/myapp-statefulset unchangedstatefulset.apps/myapp created[root@master ~]# kubectl get svcNAME                TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGEkubernetes          ClusterIP   10.96.0.1    
     
              443/TCP   2d8hmyapp-statefulset   ClusterIP   None         
      
               80/TCP    3m16s[root@master ~]# kubectl get stsNAME    READY   AGEmyapp   3/3     14s[root@master ~]# kubectl get pv        //名称都是有序的,且都是从0开始创建NAME    CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM                       STORAGECLASS   REASON   AGEpv001   5Gi        RWO,RWX        Retain           Bound       default/myappdata-myapp-2                           73spv002   5Gi        RWO,RWX        Retain           Bound       default/myappdata-myapp-1                           73spv003   5Gi        RWO,RWX        Retain           Available                                                       73spv004   5Gi        RWO,RWX        Retain           Available                                                       73spv005   5Gi        RWO,RWX        Retain           Bound       default/myappdata-myapp-0                           73s[root@master ~]# kubectl get pvcNAME                STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGEmyappdata-myapp-0   Bound    pv005    5Gi        RWO,RWX                       49smyappdata-myapp-1   Bound    pv002    5Gi        RWO,RWX                       47smyappdata-myapp-2   Bound    pv001    5Gi        RWO,RWX                       45s//删除是从2到0开始有序地删除,默认不删pvc,是为了再次创建时myapp-0自动绑定回myappdata-myapp-0//myapp-1绑定回myappdata-myapp-1,myapp-2绑定回myappdata-myapp-2[root@master ~]# kubectl delete -f myapp-statefulset.yaml service "myapp-statefulset" deletedstatefulset.apps "myapp" deleted[root@master ~]# kubectl get pods -wNAME      READY   STATUS    RESTARTS   AGEmyapp-0   1/1     Running   0          7m33smyapp-1   1/1     Running   0          7m31smyapp-2   1/1     Running   0          7m29smyapp-1   1/1     Terminating   0          7m52smyapp-0   1/1     Terminating   0          7m54smyapp-2   1/1     Terminating   0          7m50smyapp-1   0/1     Terminating   0          7m53smyapp-0   0/1     Terminating   0          7m55smyapp-2   0/1     Terminating   0          7m52smyapp-1   0/1     Terminating   0          7m58smyapp-1   0/1     Terminating   0          7m58smyapp-0   0/1     Terminating   0          8m5smyapp-0   0/1     Terminating   0          8m5smyapp-2   0/1     Terminating   0          8m1smyapp-2   0/1     Terminating   0          8m1s//创建也是按顺序来的[root@master ~]# kubectl apply -f myapp-statefulset.yaml service/myapp-statefulset createdstatefulset.apps/myapp created[root@master ~]# kubectl get pods -wNAME      READY   STATUS    RESTARTS   AGEmyapp-0   0/1     Pending   0          0smyapp-0   0/1     Pending   0          0smyapp-0   0/1     ContainerCreating   0          0smyapp-0   1/1     Running             0          2smyapp-1   0/1     Pending             0          0smyapp-1   0/1     Pending             0          0smyapp-1   0/1     ContainerCreating   0          0smyapp-1   1/1     Running             0          1smyapp-2   0/1     Pending             0          0smyapp-2   0/1     Pending             0          0smyapp-2   0/1     ContainerCreating   0          0smyapp-2   1/1     Running             0          2s

查看解析

[root@master ~]# kubectl exec -it myapp-0 -- /bin/sh/ # nslookup myapp-0nslookup: can't resolve '(null)': Name does not resolveName:      myapp-0Address 1: 10.244.3.13 myapp-0.myapp.default.svc.cluster.local/ # nslookup myapp-1.myappservice.default.svc.cluster.localnslookup: can't resolve '(null)': Name does not resolveName:      myapp-1.myappservice.default.svc.cluster.localAddress 1: 10.244.3.15 myapp-1.myappservice.default.svc.cluster.local/ # nslookup myapp-2.myappservice.default.svc.cluster.localnslookup: can't resolve '(null)': Name does not resolveName:      myapp-2.myappservice.default.svc.cluster.localAddress 1: 10.244.1.16 myapp-2.myappservice.default.svc.cluster.local/ # //解析格式nslookup myapp-0.myappservice.default.svc.cluster.localnslookup pod_name.service_name.default.svc.cluster.local

扩容

[root@master ~]# kubectl scale sts myapp --replicas=5statefulset.apps/myapp scaled[root@master ~]# kubectl get podsNAME      READY   STATUS    RESTARTS   AGEmyapp-0   1/1     Running   0          9m26smyapp-1   1/1     Running   0          9m25smyapp-2   1/1     Running   0          9m24smyapp-3   1/1     Running   0          25smyapp-4   1/1     Running   0          22s[root@master ~]# kubectl get pvcNAME                STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGEmyappdata-myapp-0   Bound    pv005    5Gi        RWO,RWX                       66mmyappdata-myapp-1   Bound    pv002    5Gi        RWO,RWX                       66mmyappdata-myapp-2   Bound    pv001    5Gi        RWO,RWX                       66mmyappdata-myapp-3   Bound    pv003    5Gi        RWO,RWX                       61smyappdata-myapp-4   Bound    pv004    5Gi        RWO,RWX                       58s[root@master ~]# kubectl get pvNAME    CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                       STORAGECLASS   REASON   AGEpv001   5Gi        RWO,RWX        Retain           Bound    default/myappdata-myapp-2                           67mpv002   5Gi        RWO,RWX        Retain           Bound    default/myappdata-myapp-1                           67mpv003   5Gi        RWO,RWX        Retain           Bound    default/myappdata-myapp-3                           67mpv004   5Gi        RWO,RWX        Retain           Bound    default/myappdata-myapp-4                           67mpv005   5Gi        RWO,RWX        Retain           Bound    default/myappdata-myapp-0                           67m

缩容

[root@master ~]# kubectl scale sts myapp --replicas=2[root@master ~]# kubectl get podNAME      READY   STATUS        RESTARTS   AGEmyapp-0   1/1     Running       0          11mmyapp-1   1/1     Running       0          11m查看默认更新策略View Code两种更新方式[root@master ~]# kubectl patch sts myapp -p '{"spec":{"template":{"containers[0]":{"image":{"ikubernetes/myapp:v2"}}}}}'[root@master ~]# kubectl set image sts/myapp myapp=ikubernetes/myapp:v2statefulset.apps/myapp image updated[root@master ~]# kubectl get sts -o wideNAME    READY   AGE   CONTAINERS   IMAGESmyapp   4/5     22m   myapp        ikubernetes/myapp:v2[root@master ~]# kubectl describe pods myapp-4Name:               myapp-4Namespace:          defaultPriority:           0PriorityClassName:  
      
       Node:               node01/10.0.1.133Start Time:         Tue, 14 May 2019 00:47:32 +0800Labels:             app=myapp-pod                    controller-revision-hash=myapp-5775ff7474                    statefulset.kubernetes.io/pod-name=myapp-4Annotations:        
       
        Status:             RunningIP:                 10.244.1.18Controlled By:      StatefulSet/myappContainers:  myapp:    Container ID:   docker://3d7e50667f84c8eab2f428c86c24cc16cae49dcb20217987fa1793e086c955a5    Image:          ikubernetes/myapp:v2    Image ID:       docker-pullable://ikubernetes/myapp@sha256:85a2b81a62f09a414ea33b74fb8aa686ed9b168294b26b4c819df0be0712d358    Port:           80/TCP    Host Port:      0/TCP    State:          Running      Started:      Tue, 14 May 2019 00:48:05 +0800    Ready:          True    Restart Count:  0    Environment:    
        
             Mounts:      /usr/share/nginx/html from myappdata (rw)      /var/run/secrets/kubernetes.io/serviceaccount from default-token-pwlvv (ro)Conditions:  Type              Status  Initialized       True   Ready             True   ContainersReady   True   PodScheduled      True Volumes:  myappdata:    Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)    ClaimName:  myappdata-myapp-4    ReadOnly:   false  default-token-pwlvv:    Type:        Secret (a volume populated by a Secret)    SecretName:  default-token-pwlvv    Optional:    falseQoS Class:       BestEffortNode-Selectors:  
         
          Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s                 node.kubernetes.io/unreachable:NoExecute for 300sEvents:  Type     Reason     Age                From               Message  ----     ------     ----               ----               -------  Normal   Scheduled  84s                default-scheduler  Successfully assigned default/myapp-4 to node01  Warning  Failed     69s                kubelet, node01    Failed to pull image "ikubernetes/myapp:v2": rpc error: code = Unknown desc = Error response from daemon: Get https://registry-1.docker.io/v2/ikubernetes/myapp/manifests/v2: Get https://auth.docker.io/token?scope=repository%3Aikubernetes%2Fmyapp%3Apull&service=registry.docker.io: net/http: TLS handshake timeout  Warning  Failed     69s                kubelet, node01    Error: ErrImagePull  Normal   BackOff    68s                kubelet, node01    Back-off pulling image "ikubernetes/myapp:v2"  Warning  Failed     68s                kubelet, node01    Error: ImagePullBackOff  Normal   Pulling    54s (x2 over 81s)  kubelet, node01    Pulling image "ikubernetes/myapp:v2"    ///版本已经变为v2  Normal   Pulled     48s                kubelet, node01    Successfully pulled image "ikubernetes/myapp:v2"  Normal   Created    48s                kubelet, node01    Created container myapp  Normal   Started    48s                kubelet, node01    Started container myapp

View Code

下面这两条命令意思是大于等于3的都更新为v2,也就是myapp-3,myapp-4的版本都更新为v2,

[root@master ~]# kubectl patch sts maypp -p '{"spec":{"updateStrategy":{"rollingUpdate":{"partition":3}}}}'[root@master ~]# kubectl set image sts/myapp myapp=ikubernetes/myapp:v2

转载于:https://www.cnblogs.com/linyouyi/p/10859994.html

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