k8s数据持久化之statefulset的数据持久化,并自动创建PV与PVC
一:Statefulset StatefulSet是为了解决有状态服务的问题,对应的Deployment和ReplicaSet是为了无状态服务而设计,其应用场景包括:1.稳定的持久化存储,即Pod重新调度后还是能访问到相同的持久化数据,基于PVC来实现2.稳定的网络标志,即Pod重新调度后其PodName和HostName不变,基于Headless Service(即没有Cluster IP的Service)来实现3.有序部署,有序扩展,即Pod是有顺序的,在部署或者扩展的时候要依据定义的顺序依次依次进行(即从0到N-1,在下一个Pod运行之前所有之前的Pod必须都是Running和Ready状态),基于init containers来实现4.有序收缩,有序删除(即从N-1到0) 因为statefulset要求Pod的名称是有顺序的,每一个Pod都不能被随意取代,也就是即使Pod重建之后,名称依然不变。为后端的每一个Pod去命名。 从上面的应用场景可以发现,StatefulSet由以下几部分组成: 1.用于定义网络标志的Headless Service(headless-svc:无头服务。因为没有IP地址,所以它不具备负载均衡的功能了。) 2.用于创建PersistentVolumes的volumeClaimTemplates 3.定义具体应用的StatefulSet StatefulSet:Pod控制器。RC、RS、Deployment、DS。 无状态的服务。template(模板):根据模板创建出来的Pod,它们的状态都是一模一样的(除了名称、IP、域名之外)可以理解为:任何一个Pod,都可以被删除,然后用新生成的Pod进行替换。 有状态的服务:需要记录前一次或者多次通信中的相关时间,以作为下一次通信的分类标准。比如:MySQL等数据库服务。(Pod的名称,不能随意变化。数据持久化的目录也是不一样,每一个Pod都有自己独有的数据持久化存储目录。) 每一个Pod-----对应一个PVC-----每一个PVC对应一个PV。 测试:要求二、以自己的名称创建一个名称空间,以下所有资源都运行在此空间中。用statefuset资源运行一个httpd web服务,要求3个Pod,但是每个Pod的主界面内容不一样,并且都要做专有的数据持久化,尝试删除其中一个Pod,查看新生成的Pod,是否数据与之前一致。 1.基于NFS服务,创建NFS服务。 1.[root@master~]#yum-yinstallnfs-utilsrpcbind2.[root@master~]#mkdir/nfsdatabr/>2.[root@master~]#mkdir/nfsdata3.[root@master~]#vim/etc/exports4./nfsdata*(rw,sync,no_root_squash)5.[root@master~]#systemctlstartnfs-server.servicebr/>4./nfsdata*(rw,sync,no_root_squash)5.[root@master~]#systemctlstartnfs-server.service6.[root@master~]#systemctlstartrpcbind7.[root@master~]#showmount-ebr/>7.[root@master~]#showmount-e8.Exportlistformaster:9./nfsdata* 2.创建RBAC权限vim rbac-rolebind.yaml apiVersion: v1 kind: Namespace metadata: name: lbs-test apiVersion: v1 kind: ServiceAccount 创建rbac授权用户。及定义权限 metadata: name: nfs-provisioner name:lbs-test --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata: name: nfs-provisioner-runner name:lbs-test rules: - apiGroups: [""] resources: ["persistentvolumes"] verbs: ["get", "list", "watch", "create", "delete"] - apiGroups: [""] resources: ["persistentvolumeclaims"] verbs: ["get", "list", "watch", "update"] - apiGroups: ["storage.k8s.io"] resources: ["storageclasses"] verbs: ["get", "list", "watch"] - apiGroups: [""] resources: ["events"] verbs: ["watch", "create", "update", "patch"] - apiGroups: [""] resources: ["services", "endpoints"] verbs: ["get","create","list", "watch","update"] - apiGroups: ["extensions"] resources: ["podsecuritypolicies"] resourceNames: ["nfs-provisioner"] verbs: ["use"] --- kind: ClusterRoleBinding apiVersion: rbac.authorization.k8s.io/v1 metadata: name: run-nfs-provisioner subjects: - kind: ServiceAccount name: nfs-provisioner namespace: lbs-test 如没有名称空间需要添加这个default默认否则报错 roleRef: kind: ClusterRole name: nfs-provisioner-runner apiGroup: rbac.authorization.k8s.io 执行yaml文件: 1.[root@masteryaml]#kubectlapply-frbac-rolebind.yaml2.namespace/lbh-testcreated3.serviceaccount/nfs-provisionercreated4.clusterrole.rbac.authorization.k8s.io/nfs-provisioner-runnercreated5.clusterrolebinding.rbac.authorization.k8s.io/run-nfs-provisionercreated 3.创建Deployment资源对象。 [root@master yaml]# vim nfs-deployment.yaml apiVersion: extensions/v1beta1 kind: Deployment metadata: name: nfs-client-provisioner name:lbs-test spec: replicas: 1#副本数量为1 strategy: type: Recreate#重置 template: metadata: labels: app: nfs-client-provisioner spec: serviceAccount: nfs-provisioner#指定账户 containers: - name: nfs-client-provisioner image: registry.cn-hangzhou.aliyuncs.com/open-ali/nfs-client-provisioner使用的是这个镜像。 volumeMounts: - name: nfs-client-root mountPath: /persistentvolumes#指定容器内的挂载目录 env: - name: PROVISIONER_NAME#容器内置变量 value: bdqn#这是变量的名字 - name: NFS_SERVER value: 192.168.1.1 - name: NFS_PATH#指定Nfs的共享目录 value: /nfsdata volumes:#指定挂载到容器内的nfs路径与IP - name: nfs-client-root nfs: server: 192.168.1.1 path: /nfsdata 执行yaml文件,查看Pod:1.[root@masteryaml]#kubectlapply-fnfs-deployment.yamlbr/>1.[root@masteryaml]#kubectlapply-fnfs-deployment.yaml2.deployment.extensions/nfs-client-provisionercreated3.[root@masteryaml]#kubectlgetpod-nlbs-testbr/>3.[root@masteryaml]#kubectlgetpod-nlbs-test4.NAMEREADYSTATUSRESTARTSAGE5.nfs-client-provisioner-5d88975f6d-wdbnc1/1Running013s 4.创建Storageclass资源对象(sc): root@master yaml]# vim sc.yaml apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: sc-nfs namespace:lbs-test #名称空间 名 provisioner: lbs-test#与deployment资源的env环境变量value值相同 reclaimPolicy: Retain #回收策略 执行yaml文件,查看SC:1.[root@masteryaml]#kubectlapply-fsc.yamlbr/>1.[root@masteryaml]#kubectlapply-fsc.yaml2.storageclass.storage.k8s.io/sc-nfscreated3.[root@masteryaml]#kubectlgetsc-nlbs-testbr/>3.[root@masteryaml]#kubectlgetsc-nlbs-test4.NAMEPROVISIONERAGE5.sc-nfslbs-test8s 5.创建StatefulSet资源对象,自动创建PVC: vim statefulset.yaml apiVersion: v1 kind: Service metadata: name: headless-svc namespace: lbs-test labels: app: headless-svc spec: ports: - port: 80 name: myweb selector: app: headless-pod clusterIP: None --- apiVersion: apps/v1 kind: StatefulSet metadata: name: statefulset-test namespace: lbs-test spec: serviceName: headless-svc replicas: 3 selector: matchLabels: app: headless-pod template: metadata: labels: app: headless-pod spec: containers: - image: httpd name: myhttpd ports: - containerPort: 80 name: httpd volumeMounts: - mountPath: /mnt name: test volumeClaimTemplates: 这个字段:自动创建PVC - metadata: name: test annotations: //这是指定storageclass,名称要一致 volume.beta.kubernetes.io/storage-class: sc-nfs spec: accessModes: - ReadWriteOnce resources: requests: storage: 100Mi 执行yaml文件,查看Pod:1.[root@masteryaml]#kubectlapply-fstatefulset.yamlbr/>1.[root@masteryaml]#kubectlapply-fstatefulset.yaml2.service/headless-svccreated3.statefulset.apps/statefulset-testcreated4.[root@masteryaml]#kubectlgetpod-nlbs-testbr/>3.statefulset.apps/statefulset-testcreated4.[root@masteryaml]#kubectlgetpod-nlbs-test5.NAMEREADYSTATUSRESTARTSAGE6.nfs-client-provisioner-5d88975f6d-wdbnc1/1Running022m 7.statefulset-test-01/1Running08m59s8.statefulset-test-11/1Running02m30s9.statefulset-test-21/1Running0109s **查看是否自动创建PV及PVC** PV: 1.[root@masteryaml]#kubectlgetpv-nlbs-test 2.NAMECAPACITYACCESSMODESRECLAIMPOLICYSTATUSCLAIMSTORAGECLASSREASONAGE 3.pvc-0454e9ad-892f-4e39-8dcb-79664f65d1e5100MiRWODeleteBoundlbh-test/test-statefulset-test-2sc-nfs4m23s 4.pvc-2cb98c60-977f-4f3b-ba97-b84275f3b9e5100MiRWODeleteBoundlbh-test/test-statefulset-test-0sc-nfs11m 5.pvc-99137753-ccd0-4524-bf40-f3576fc97eba100MiRWODeleteBoundlbh-test/test-statefulset-test-1sc-nfs5m4s PVC: 1.[root@masteryaml]#kubectlgetpvc-nlbs-test 2.NAMESTATUSVOLUMECAPACITYACCESSMODESSTORAGECLASSAGE 3.test-statefulset-test-0Boundpvc-2cb98c60-977f-4f3b-ba97-b84275f3b9e5100MiRWOsc-nfs13m 4.test-statefulset-test-1Boundpvc-99137753-ccd0-4524-bf40-f3576fc97eba100MiRWOsc-nfs6m42s 5.test-statefulset-test-2Boundpvc-0454e9ad-892f-4e39-8dcb-79664f65d1e5100MiRWOsc-nfs6m1s 查看是否创建持久化目录: 1.[root@masteryaml]#ls/nfsdata/2.lbh-test-test-statefulset-test-0-pvc-2cb98c60-977f-4f3b-ba97-b84275f3b9e53.lbh-test-test-statefulset-test-1-pvc-99137753-ccd0-4524-bf40-f3576fc97eba4.lbh-test-test-statefulset-test-2-pvc-0454e9ad-892f-4e39-8dcb-79664f65d1e5 6.在pod资源内创建数据。并访问测试。 1.[root@masteryaml]#cd/nfsdata/ 2.[root@masternfsdata]#echo111>lbs-test-test-statefulset-test-0-pvc-2cb98c60-977f-4f3b-ba97-b84275f3b9e5/index.html 3.[root@masternfsdata]#echo222>lbs-test-test-statefulset-test-1-pvc-99137753-ccd0-4524-bf40-f3576fc97eba/index.html 4.[root@masternfsdata]#echo333>lbs-test-test-statefulset-test-2-pvc-0454e9ad-892f-4e39-8dcb-79664f65d1e5/index.html 5.[root@masternfsdata]#kubectlgetpod-owide-nlbs-test 6.NAMEREADYSTATUSRESTARTSAGEIPNODENOMINATEDNODEREADINESSGATES 7.nfs-client-provisioner-5d88975f6d-wdbnc1/1Running030m10.244.2.2node02<none><none> 8.statefulset-test-01/1Running017m10.244.1.2node01<none><none> 9.statefulset-test-11/1Running010m10.244.2.3node02<none><none> 10.statefulset-test-21/1Running09m57s10.244.1.3node01<none><none> 11.[root@masternfsdata]#curl10.244.1.2 12.111 13.[root@masternfsdata]#curl10.244.2.3 14.222 15.[root@masternfsdata]#curl10.244.1.3 16.333 7.删除其中一个pod,查看该pod资源的数据是否会**重新创建并存在。** 1.[root@master~]#kubectlgetpod-nlbs-test 2.NAMEREADYSTATUSRESTARTSAGE 3.nfs-client-provisioner-5d88975f6d-wdbnc1/1Running033m 4.statefulset-test-01/1Running020m 5.statefulset-test-11/1Running013m 6.statefulset-test-21/1Running013m 7.[root@master~]#kubectldeletepod-nlbs-teststatefulset-test-0 8.pod"statefulset-test-0"deleted **9.删除后会重新创建pod资源** 10.[root@master~]#kubectlgetpod-nlbs-test-owide 11.NAMEREADYSTATUSRESTARTSAGEIPNODENOMINATEDNODEREADINESSGATES 12.nfs-client-provisioner-5d88975f6d-wdbnc1/1Running035m10.244.2.2node02<none><none> 13.statefulset-test-01/1Running051s10.244.1.4node01<none><none> 14.statefulset-test-11/1Running015m10.244.2.3node02<none><none> 15.statefulset-test-21/1Running014m10.244.1.3node01<none><none> **数据依旧存在。** 16.[root@master~]#curl10.244.1.4 17.111 18.[root@master~]#cat/nfsdata/lbs-test-test-statefulset-test-0-pvc-2cb98c60-977f-4f3b-ba97-b84275f3b9e5/index.html 19.111 StatefulSet资源对象,针对有状态的服务的数据持久化测试完成。通过测试,即使删除Pod,重新生成调度后,依旧能访问到之前的持久化数据。