基于K8S的StatefulSet部署MySQL集群

2025-05-27 0 85

基于K8S的StatefulSet部署MySQL集群

环境:

基于K8S的StatefulSet部署MySQL集群

# 采用NFS存储卷的方式 持久化存储mysql数据目录

需求:

展示如何使用 StatefulSet 控制器运行一个有状态的应用程序。此例是多副本的 MySQL 数据库。 示例应用的拓扑结构有一个主服务器和多个副本,使用异步的基于行(Row-Based) 的数据复制。

基于K8S的StatefulSet部署MySQL集群

  • 搭建一个“主从复制”(Maser-Slave Replication)的 MySQL 集群
  • 存在一个主节点【master】,有多个从节点【slave】
  • 从节点可以水平拓展
  • 所有的写操作,只能在主节点上执行
  • 读操作可以在所有节点上执行

一、部署NFS服务器

  1. #服务器安装nfs服务,提供nfs存储功能
  2. 1、安装nfs-utils
  3. yuminstallnfs-utils(centos)
  4. 或者apt-getinstallnfs-kernel-server(ubuntu)
  5. 2、启动服务
  6. systemctlenablenfs-server
  7. systemctlstartnfs-server
  8. 3、创建共享目录完成共享配置
  9. mkdir/home/nfs#创建共享目录
  10. 4、编辑共享配置
  11. vim/etc/exports
  12. #语法格式:共享文件路径客户机地址(权限)#这里的客户机地址可以是IP,网段,域名,也可以是任意*
  13. /home/nfs*(rw,async,no_root_squash)
  1. #服务器安装nfs服务,提供nfs存储功能
  2. 1、安装nfs-utils
  3. yuminstallnfs-utils(centos)
  4. 或者apt-getinstallnfs-kernel-server(ubuntu)
  5. 2、启动服务
  6. systemctlenablenfs-server
  7. systemctlstartnfs-server
  8. 3、创建共享目录完成共享配置
  9. mkdir/home/nfs#创建共享目录
  10. 4、编辑共享配置
  11. vim/etc/exports
  12. #语法格式:共享文件路径客户机地址(权限)#这里的客户机地址可以是IP,网段,域名,也可以是任意*
  13. /home/nfs*(rw,async,no_root_squash)
  1. 服务自检命令
  2. exportfs-arv
  3. 5、重启服务
  4. systemctlrestartnfs-server
  5. 6、本机查看nfs共享目录
  6. #showmount-e服务器IP地址(如果提示命令不存在,则需要yuminstallshowmount)
  7. showmount-e127.0.0.1
  8. /home/nfs*
  9. 7、客户端模拟挂载[所有k8s的节点都需要安装客户端]
  10. [root@master-1~]#yuminstallnfs-utils(centos)
  11. 或者apt-getinstallnfs-common(ubuntu)
  12. [root@master-1~]#mkdir/test
  13. [root@master-1~]#mount-tnfs172.16.201.209:/home/nfs/test
  14. #取消挂载
  15. [root@master-1~]#umount/test

二、配置PV 动态供给(NFS StorageClass),创建pvc

部署NFS实现自动创建PV插件: 一共设计到4个yaml 文件 ,官方的文档有详细的说明

https://github.com/kubernetes-incubator/external-storage

基于K8S的StatefulSet部署MySQL集群

基于K8S的StatefulSet部署MySQL集群

  1. root@k8s-master1:~#mkdir/root/pvc
  2. root@k8s-master1:~#cd/root/pvc

创建rbac.yaml 文件

  1. root@k8s-master1:pvc#catrbac.yaml
  2. kind:ServiceAccount
  3. apiVersion:v1
  4. metadata:
  5. name:nfs-client-provisioner
  6. kind:ClusterRole
  7. apiVersion:rbac.authorization.k8s.io/v1
  8. metadata:
  9. name:nfs-client-provisioner-runner
  10. rules:
  11. -apiGroups:[""]
  12. resources:["persistentvolumes"]
  13. verbs:["get","list","watch","create","delete"]
  14. -apiGroups:[""]
  15. resources:["persistentvolumeclaims"]
  16. verbs:["get","list","watch","update"]
  17. -apiGroups:["storage.k8s.io"]
  18. resources:["storageclasses"]
  19. verbs:["get","list","watch"]
  20. -apiGroups:[""]
  21. resources:["events"]
  22. verbs:["create","update","patch"]
  23. kind:ClusterRoleBinding
  24. apiVersion:rbac.authorization.k8s.io/v1
  25. metadata:
  26. name:run-nfs-client-provisioner
  27. subjects:
  28. -kind:ServiceAccount
  29. name:nfs-client-provisioner
  30. namespace:default
  31. roleRef:
  32. kind:ClusterRole
  33. name:nfs-client-provisioner-runner
  34. apiGroup:rbac.authorization.k8s.io
  35. kind:Role
  36. apiVersion:rbac.authorization.k8s.io/v1
  37. metadata:
  38. name:leader-locking-nfs-client-provisioner
  39. rules:
  40. -apiGroups:[""]
  41. resources:["endpoints"]
  42. verbs:["get","list","watch","create","update","patch"]
  43. kind:RoleBinding
  44. apiVersion:rbac.authorization.k8s.io/v1
  45. metadata:
  46. name:leader-locking-nfs-client-provisioner
  47. subjects:
  48. -kind:ServiceAccount
  49. name:nfs-client-provisioner
  50. #replacewithnamespacewhereprovisionerisdeployed
  51. namespace:default
  52. roleRef:
  53. kind:Role
  54. name:leader-locking-nfs-client-provisioner
  55. apiGroup:rbac.authorization.k8s.io

创建deployment.yaml 文件

官方默认的镜像地址,国内可能无法下载,可以使用 image:

fxkjnj/nfs-client-provisioner:latest

#定义NFS 服务器的地址,共享目录名称

  1. root@k8s-master1:pvc#catdeployment.yaml
  2. apiVersion:v1
  3. kind:ServiceAccount
  4. metadata:
  5. name:nfs-client-provisioner
  6. kind:Deployment
  7. apiVersion:apps/v1
  8. metadata:
  9. name:nfs-client-provisioner
  10. spec:
  11. replicas:1
  12. strategy:
  13. type:Recreate
  14. selector:
  15. matchLabels:
  16. app:nfs-client-provisioner
  17. template:
  18. metadata:
  19. labels:
  20. app:nfs-client-provisioner
  21. spec:
  22. serviceAccountName:nfs-client-provisioner
  23. containers:
  24. name:nfs-client-provisioner
  25. image:fxkjnj/nfs-client-provisioner:latest
  26. volumeMounts:
  27. name:nfs-client-root
  28. mountPath:/persistentvolumes
  29. env:
  30. name:PROVISIONER_NAME
  31. value:fuseim.pri/ifs
  32. name:NFS_SERVER
  33. value:172.16.201.209
  34. name:NFS_PATH
  35. value:/home/nfs
  36. volumes:
  37. name:nfs-client-root
  38. nfs:
  39. server:172.16.201.209
  40. path:/home/nfs

创建class.yaml

  1. root@k8s-master1:pvc#catclass.yaml
  2. apiVersion:storage.k8s.io/v1
  3. kind:StorageClass
  4. metadata:
  5. name:managed-nfs-storage
  6. provisioner:fuseim.pri/ifs#orchooseanothername,mustmatchdeployment'senvPROVISIONER_NAME'
  7. parameters:
  8. archiveOnDelete:"true"

部署

  1. root@k8s-master1:pvc#kubectlapply-f.
  2. #查看存储卷
  3. root@k8s-master1:pvc#kubectlgetsc
  4. NAMEPROVISIONERRECLAIMPOLICYVOLUMEBINDINGMODEALLOWVOLUMEEXPANSIONAGE
  5. managed-nfs-storagefuseim.pri/ifsDeleteImmediatefalse25h

三、编写mysql 相关yaml文件

MySQL 示例部署包含一个 ConfigMap、两个 Service 与一个 StatefulSet

ConfigMap:

vim mysql-configmap.yaml

  1. apiVersion:v1
  2. kind:ConfigMap
  3. metadata:
  4. name:mysql
  5. labels:
  6. app:mysql
  7. data:
  8. master.cnf:|
  9. #Applythisconfigonlyonthemaster.
  10. [mysqld]
  11. log-bin
  12. slave.cnf:|
  13. #Applythisconfigonlyonslaves.
  14. [mysqld]
  15. super-readonly

说明:

在这里,我们定义了 master.cnf 和 slave.cnf 两个 MySQL 的配置文件

  • master.cnf 开启了log-bin,可以使用二进制日志文件的方式进行主从复制.
  • slave.cnf 开启了 super-read-only ,表示从节点只接受主节点的数据同步的所有写的操作,拒绝其他的写入操作,对于用户来说就是只读的
  • master.cnf 和 slave.cnf 已配置文件的形式挂载到容器的目录中

Service:

vim mysql-services.yaml

  1. #HeadlessserviceforstableDNSentriesofStatefulSetmembers.
  2. apiVersion:v1
  3. kind:Service
  4. metadata:
  5. name:mysql
  6. labels:
  7. app:mysql
  8. spec:
  9. ports:
  10. name:mysql
  11. port:3306
  12. clusterIP:None
  13. selector:
  14. app:mysql
  15. #ClientserviceforconnectingtoanyMySQLinstanceforreads.
  16. #Forwrites,youmustinsteadconnecttothemaster:mysql-0.mysql.
  17. apiVersion:v1
  18. kind:Service
  19. metadata:
  20. name:mysql-read
  21. labels:
  22. app:mysql
  23. spec:
  24. ports:
  25. name:mysql
  26. port:3306
  27. selector:
  28. app:mysql

说明:

clusterIP: None,使用无头服务 Headless Service(相比普通Service只是将spec.clusterIP定义为None,也就是没有clusterIP,直接使用endport 来通信)来维护Pod网络身份,会为每个Pod分配一个数字编号并且按照编号顺序部署。还需要在StatefulSet添加serviceName: “mysql”字段指定StatefulSet控制器

另外statefulset控制器网络标识,体现在主机名和Pod A记录:

• 主机名:-<编号>

例如: mysql-0

• Pod DNS A记录:. ..svc.cluster.local (POD 之间通过DNS A 记录互相通信)

例如:

mysql-0.mysql.default.svc.cluster.local

StatefulSet:

vim mysql-statefulset.yaml

  1. apiVersion:apps/v1
  2. kind:StatefulSet
  3. metadata:
  4. name:mysql
  5. spec:
  6. selector:
  7. matchLabels:
  8. app:mysql
  9. serviceName:mysql
  10. replicas:3
  11. template:
  12. metadata:
  13. labels:
  14. app:mysql
  15. spec:
  16. initContainers:
  17. name:init-mysql
  18. image:mysql:5.7
  19. command:
  20. -bash
  21. "-c"
  22. -|
  23. set-ex
  24. #Generatemysqlserver-idfrompodordinalindex.
  25. [[`hostname`=~-([0-9]+)$]]||exit1
  26. ordinal=${BASH_REMATCH[1]}
  27. echo[mysqld]>/mnt/conf.d/server-id.cnf
  28. #Addanoffsettoavoidreservedserver-id=0value.
  29. echoserver-id=$((100+$ordinal))>>/mnt/conf.d/server-id.cnf
  30. #Copyappropriateconf.dfilesfromconfig-maptoemptyDir.
  31. if[[$ordinal-eq0]];then
  32. cp/mnt/config-map/master.cnf/mnt/conf.d/
  33. else
  34. cp/mnt/config-map/slave.cnf/mnt/conf.d/
  35. fi
  36. volumeMounts:
  37. name:conf
  38. mountPath:/mnt/conf.d
  39. name:config-map
  40. mountPath:/mnt/config-map
  41. name:clone-mysql
  42. image:fxkjnj/xtrabackup:1.0
  43. command:
  44. -bash
  45. "-c"
  46. -|
  47. set-ex
  48. #Skipthecloneifdataalreadyexists.
  49. [[-d/var/lib/mysql/mysql]]&&exit0
  50. #Skipthecloneonmaster(ordinalindex0).
  51. [[`hostname`=~-([0-9]+)$]]||exit1
  52. ordinal=${BASH_REMATCH[1]}
  53. [[$ordinal-eq0]]&&exit0
  54. #Clonedatafrompreviouspeer.
  55. ncat–recv-onlymysql-$(($ordinal-1)).mysql3307|xbstream-x-C/var/lib/mysql
  56. #Preparethebackup.
  57. xtrabackup–prepare–target-dir=/var/lib/mysql
  58. volumeMounts:
  59. name:data
  60. mountPath:/var/lib/mysql
  61. subPath:mysql
  62. name:conf
  63. mountPath:/etc/mysql/conf.d
  64. containers:
  65. name:mysql
  66. image:mysql:5.7
  67. env:
  68. name:MYSQL_ALLOW_EMPTY_PASSWORD
  69. value:"1"
  70. ports:
  71. name:mysql
  72. containerPort:3306
  73. volumeMounts:
  74. name:data
  75. mountPath:/var/lib/mysql
  76. subPath:mysql
  77. name:conf
  78. mountPath:/etc/mysql/conf.d
  79. resources:
  80. requests:
  81. cpu:500m
  82. memory:1Gi
  83. livenessProbe:
  84. exec:
  85. command:["mysqladmin","ping"]
  86. initialDelaySeconds:30
  87. periodSeconds:10
  88. timeoutSeconds:5
  89. readinessProbe:
  90. exec:
  91. #CheckwecanexecutequeriesoverTCP(skip-networkingisoff).
  92. command:["mysql","-h","127.0.0.1","-e","SELECT1"]
  93. initialDelaySeconds:5
  94. periodSeconds:2
  95. timeoutSeconds:1
  96. name:xtrabackup
  97. image:fxkjnj/xtrabackup:1.0
  98. ports:
  99. name:xtrabackup
  100. containerPort:3307
  101. command:
  102. -bash
  103. "-c"
  104. -|
  105. set-ex
  106. cd/var/lib/mysql
  107. #Determinebinlogpositionofcloneddata,ifany.
  108. if[[-fxtrabackup_slave_info&&"x$(<xtrabackup_slave_info)\"!="x"]];then</xtrabackup_slave_info)\"
  109. #XtraBackupalreadygeneratedapartial"CHANGEMASTERTO"query
  110. #becausewe'recloningfromanexistingslave.(Needtoremovethetailingsemicolon!)
  111. catxtrabackup_slave_info|sed-E's/;$//g'>change_master_to.sql.in
  112. #Ignorextrabackup_binlog_infointhiscase(it'suseless).
  113. rm-fxtrabackup_slave_infoxtrabackup_binlog_info
  114. elif[[-fxtrabackup_binlog_info]];then
  115. #We'recloningdirectlyfrommaster.Parsebinlogposition.
  116. [[`catxtrabackup_binlog_info`=~^(.*?)[[:space:]]+(.*?)$]]||exit1
  117. rm-fxtrabackup_binlog_infoxtrabackup_slave_info
  118. echo"CHANGEMASTERTOMASTER_LOG_FILE='${BASH_REMATCH[1]}',\\
  119. MASTER_LOG_POS=${BASH_REMATCH[2]}">change_master_to.sql.in
  120. fi
  121. #Checkifweneedtocompleteaclonebystartingreplication.
  122. if[[-fchange_master_to.sql.in]];then
  123. echo"Waitingformysqldtobeready(acceptingconnections)"
  124. untilmysql-h127.0.0.1-e"SELECT1";dosleep1;done
  125. echo"Initializingreplicationfromcloneposition"
  126. mysql-h127.0.0.1\\
  127. -e"$(<change_master_to.sql.in</change_master_to.sql.),\\
  128. MASTER_HOST='mysql-0.mysql',\\
  129. MASTER_USER='root',\\
  130. MASTER_PASSWORD='',\\
  131. MASTER_CONNECT_RETRY=10;\\
  132. STARTSLAVE;"||exit1
  133. #Incaseofcontainerrestart,attemptthisat-most-once.
  134. mvchange_master_to.sql.inchange_master_to.sql.orig
  135. fi
  136. #Startaservertosendbackupswhenrequestedbypeers.
  137. execncat–listen–keep-open–send-only–max-conns=13307-c\\
  138. "xtrabackup–backup–slave-info–stream=xbstream–host=127.0.0.1–user=root"
  139. volumeMounts:
  140. name:data
  141. mountPath:/var/lib/mysql
  142. subPath:mysql
  143. name:conf
  144. mountPath:/etc/mysql/conf.d
  145. resources:
  146. requests:
  147. cpu:100m
  148. memory:100Mi
  149. volumes:
  150. name:conf
  151. emptyDir:{}
  152. name:config-map
  153. configMap:
  154. name:mysql
  155. volumeClaimTemplates:
  156. -metadata:
  157. name:data
  158. spec:
  159. storageClassName:"managed-nfs-storage"
  160. accessModes:["ReadWriteOnce"]
  161. resources:
  162. requests:
  163. storage:0.5Gi

说明:

  • 使用xtrbackup 工具进行容器初始化数据的备份,https://www.toutiao.com/i6999565563710292484
  • 使用linux 自带的ncat 工具进行容器初始化数据的拷贝[使用ncat指令,远程地从前一个节点拷贝数据到本地] https://www.cnblogs.com/chengd/p/7565280.html
  • 使用mysql的binlog 主从复制 来保证主从之间的数据一致
  • 利用pod的主机名的序号来判断当前节点为主节点还是从节点,再根据对于节点拷贝不同的配置文件到指定位置
  • 使用mysqladmin的ping 作为数据库的健康检测方式
  • 使用nfs存储的 PV 动态供给(StorageClass),持久化mysql的数据文件

四、部署并测试

  1. root@k8s-master1:~/kubernetes/mysql#ll
  2. total24
  3. drwxr-xr-x2rootroot4096Nov316:42./
  4. drwxr-xr-x8rootroot4096Nov313:33../
  5. -rw-r–r–1rootroot278Nov222:15mysql-configmap.yaml
  6. -rw-r–r–1rootroot556Nov222:08mysql-services.yaml
  7. -rw-r–r–1rootroot5917Nov314:22mysql-statefulset.yaml
  8. root@k8s-master1:~/kubernetes/mysql#kubectlapply-f.
  9. configmap/mysqlcreate
  10. service/mysqlcreate
  11. service/mysql-readcreate
  12. statefulset.apps/mysqlcreate
  13. #动态追踪查看Pod的状态:
  14. root@k8s-master1:~/kubernetes/mysql#kubectlgetpods-lapp=mysql–watch
  15. NAMEREADYSTATUSRESTARTSAGE
  16. mysql-02/2Running03h12m
  17. mysql-12/2Running03h11m
  18. mysql-22/2Running03h10m

可以看到,StatefulSet 启动成功后,将会有三个 Pod 运行。

接下来,我们可以尝试向这个 MySQL 集群发起请求,执行一些 SQL 操作来验证它是否正常:

  1. kubectlrunmysql-client–image=mysql:5.7-i–rm–restart=Never–\\
  2. mysql-hmysql-0.mysql<<eof </eof
  3. CREATEDATABASEtest;
  4. CREATETABLEtest.messages(messageVARCHAR(250));
  5. INSERTINTOtest.messagesVALUES('hello');
  6. EOF

如上所示,我们通过启动一个容器,使用 MySQL client 执行了创建数据库和表、以及插入数据的操作。需要注意的是,我们连接的 MySQL 的地址必须是 mysql-0.mysql(即:Master 节点的 DNS A 记录, 因为POD 之间通过DNS A 记录互相通信)只有 Master 节点才能处理写操作。

而通过连接 mysql-read 这个 Service,我们就可以用 SQL 进行读操作,如下所示:

  1. kubectlrunmysql-client–image=mysql:5.7-i-t–rm–restart=Never–\\
  2. mysql-hmysql-read-e"SELECT*FROMtest.messages"
  3. #你应该获得如下输出:
  4. Waitingforpoddefault/mysql-clienttoberunning,statusisPending,podready:false
  5. +———+
  6. |message|
  7. +———+
  8. |hello|
  9. +———+
  10. pod"mysql-client"deleted

或者:

  1. root@k8s-master1:~/kubernetes/mysql#kubectlrun-it–rm–image=mysql:5.7–restart=Nevermysql-client–mysql-hmysql-read
  2. Ifyoudon'tseeacommandprompt,trypressingenter.
  3. WelcometotheMySQLmonitor.Commandsendwith;or\\g.
  4. YourMySQLconnectionidis7251
  5. Serverversion:5.7.36MySQLCommunityServer(GPL)
  6. Copyright(c)2000,2021,Oracleand/oritsaffiliates.
  7. OracleisaregisteredtrademarkofOracleCorporationand/orits
  8. affiliates.Othernamesmaybetrademarksoftheirrespective
  9. owners.
  10. Type'help;'or'\\h'forhelp.Type'\\c'toclearthecurrentinputstatement.
  11. mysql>SELECT*FROMtest.messages;
  12. +———+
  13. |message|
  14. +———+
  15. |hello|
  16. +———+
  17. 1rowinset(0.00sec)
  18. mysql>

原文链接:https://www.toutiao.com/a7026278182844350984/

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