详细介绍MongoDB复制集
发布时间：2023-10-25 15:06:16 所属栏目：系统 来源：
导读：何为复制集？
复制集是额外的数据副本，是跨多个服务器同步数据的过程，复制集提供了冗余并增加了数据可用性，通过复制集可以对硬件故障和中断的服务进行恢复。
复制集主从同步的原理和mysql类似，主节点记录
复制集是额外的数据副本，是跨多个服务器同步数据的过程，复制集提供了冗余并增加了数据可用性，通过复制集可以对硬件故障和中断的服务进行恢复。
复制集主从同步的原理和mysql类似，主节点记录
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何为复制集？ 复制集是额外的数据副本，是跨多个服务器同步数据的过程，复制集提供了冗余并增加了数据可用性，通过复制集可以对硬件故障和中断的服务进行恢复。 复制集主从同步的原理和mysql类似，主节点记录在其上的所有操作到oplog中，从节点定期轮询主节点获取这些操作，然后对自己的数据副本执行这些操作，从而保证从节点的数据与主节点一致。 复制集的优势如下： （1）让数据更安全 （2）高数据可用性（24*7） （3）灾难恢复 （4）无停机维护（如备份、索引重建、故障转移） （5）读缩放（额外的副本读取） （6）副本集对应用程序是透明。 .mongodb的复制集至少需要两个节点。其中一个是主节点(Primary)，负责处理客户端请求，其余的都是从节点(Secondary)，负责复制主节点上的数据。 mongodb各个节点常见的搭配方式为：一主一从或一主多从。 客户端在主节点写入数据，在从节点读取数据，主节点与从节点进行数据交互，保障数据的一致性。如果其中一个节点出现故障，其他节点马上会将业务接过来而无需停机操作 详解MongoDB复制集 复制集的特点： 1.N 个节点的集群 2.任何节点可作为主节点 3.所有写入操作都在主节点上 4.自动故障转移 5.自动恢复 MongoDB复制集部署 在一台CentOS7主机上使用yum在线安装Mongodb，并创建多实例，进行部署MongoDB复制集 首先配置网络YUM源，baseurl（下载路径）指定为mongodb官网提供的yum仓库 vim /etc/yum.repos.d/mongodb.repo [mongodb-org] name=MongoDB Repository baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/3.6/x86_64/ #指定获得下载的路径 gpgcheck=1 #表示对从这个源下载的rpm包进行校验 enabled=1 #表示启用这个源。 gpgkey=https://www.mongodb.org/static/pgp/server-3.6.asc 重新加载yum源，并使用yum命令下载安装mongodb yum list yum -y install mongodb-org 准备4个实例，暂时开启3个， 1主2从 再额外添加群集（追加实例）也可以撤销实例 创建数据文件和日志文件存储路径，并赋予权限 [root@localhost ~]# mkdir -p /data/mongodb{2,3,4} [root@localhost ~]# mkdir /data/logs [root@localhost ~]# touch /data/logs/mongodb{2,3,4}.log [root@localhost ~]# chmod 777 /data/logs/mongodb* [root@localhost ~]# ll /data/logs/ 总用量 0 -rwxrwxrwx. 1 root root 0 9月 15 22:31 mongodb2.log -rwxrwxrwx. 1 root root 0 9月 15 22:31 mongodb3.log -rwxrwxrwx. 1 root root 0 9月 15 22:31 mongodb4.log 编辑4个MongoDB实例的配置文件 先编辑yum安装的默认实例的配置文件/etc/mongod.conf，指定监听IP，端口默认为27017，开启replication参数配置，replSetName：true（自定义） [root@localhost ~]# vim /etc/mongod.conf # mongod.conf # for documentation of all options, see: # http://docs.mongodb.org/manual/reference/configuration-options/ # where to write logging data. systemLog: destination: file logAppend: true path: /var/log/mongodb/mongod.log # Where and how to store data. storage: dbPath: /var/lib/mongo journal: enabled: true # engine: # mmapv1: # wiredTiger: # how the process runs processManagement: fork: true # fork and run in background pidFilePath: /var/run/mongodb/mongod.pid # location of pidfile timeZoneInfo: /usr/share/zoneinfo # network interfaces net: port: 27017 #默认端口 bindIp: 0.0.0.0 #监听任意地址 #security: #operationProfiling: replication: #去掉前面的“#”注释，开启该参数设置 replSetName: true #设置复制集名称 复制配置文件给其他实例，并将mongodb2.conf 中的port参数配置为27018，mongod3.conf中的port参数配置为27019，mongod4.conf中的port参数配置为27020。 同样也将dbpath和logpath参数修改为对应的路径值 cp /etc/mongod.conf /etc/mongod2.conf cp /etc/mongod2.conf /etc/mongod3.conf cp /etc/mongod2.conf /etc/mongod4.conf 实例2的配置文件mongodb2.conf 修改 vim /etc/mongod2.conf systemLog: destination: file logAppend: true path: /data/logs/mongodb2.log storage: dbPath: /data/mongodb/mongodb2 journal: enabled: true port: 27018 bindIp: 0.0.0.0 # Listen to local interface only, comment to listen on all interfaces. #security: #operationProfiling: replication: replSetName: true 实例3的配置文件mongodb3.conf 修改 vim /etc/mongod3.conf systemLog: destination: file logAppend: true path: /data/logs/mongodb3.log storage: dbPath: /data/mongodb/mongodb3 journal: enabled: true port: 27019 bindIp: 0.0.0.0 # Listen to local interface only, comment to listen on all interfaces. #security: #operationProfiling: replication: replSetName: true 实例4的配置文件mongodb4.conf 修改 vim /etc/mongod4.conf systemLog: destination: file logAppend: true path: /data/logs/mongodb4.log storage: dbPath: /data/mongodb/mongodb4 journal: enabled: true port: 27020 bindIp: 0.0.0.0 # Listen to local interface only, comment to listen on all interfaces. #security: #operationProfiling: replication: replSetName: true 启动mongodb各实例 [root@localhost ~]# mongod -f /etc/mongod.conf about to fork child process, waiting until server is ready for connections. forked process: 93576 child process started successfully, parent exiting [root@localhost ~]# mongod -f /etc/mongod2.conf about to fork child process, waiting until server is ready for connections. forked process: 93608 child process started successfully, parent exiting [root@localhost ~]# mongod -f /etc/mongod3.conf about to fork child process, waiting until server is ready for connections. forked process: 93636 child process started successfully, parent exiting [root@localhost ~]# mongod -f /etc/mongod4.conf about to fork child process, waiting until server is ready for connections. forked process: 93664 child process started successfully, parent exiting [root@localhost ~]# netstat -antp | grep mongod //查看mongodb进程状态 tcp 0 0 0.0.0.0:27019 0.0.0.0:* LISTEN 93636/mongod tcp 0 0 0.0.0.0:27020 0.0.0.0:* LISTEN 93664/mongod tcp 0 0 0.0.0.0:27017 0.0.0.0:* LISTEN 93576/mongod tcp 0 0 0.0.0.0:27018 0.0.0.0:* LISTEN 93608/mongod 配置三个节点的复制集 [root@localhost ~]# mongo //进入其中一个实例 MongoDB shell version v3.6.7 connecting to: mongodb://127.0.0.1:27017 MongoDB server version: 3.6.7 > rs.status() //查看复制集状态，提示复制集还未配置 { "info" : "run rs.initiate(...) if not yet done for the set", "ok" : 0, "errmsg" : "no replset config has been received", "code" : 94, "codeName" : "NotYetInitialized", "operationTime" : Timestamp(0, 0), "$clusterTime" : { "clusterTime" : Timestamp(0, 0), "signature" : { "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="), "keyId" : NumberLong(0) } } > cfg={"_id":"true","members":[{"_id":0,"host":"192.168.195.137:27017"},{"_id":1,"host":"192.168.195.137:27018"},{"_id":2,"host":"192.168.195.137:27019"}]} // 定义cfg初始化参数 { "_id" : "true", "members" : [ { "_id" : 0, "host" : "192.168.195.137:27017" }, { "_id" : 1, "host" : "192.168.195.137:27018" }, { "_id" : 2, "host" : "192.168.195.137:27019" } ] } > rs.initiate(cfg) //初始化并启动复制集 {"ok" : 1} true:PRIMARY> rs.status() //再次查看复制集的状态信息 { "set" : "true", "date" : ISODate("2018-09-15T15:39:48.426Z"), "myState" : 1, "term" : NumberLong(1), "syncingTo" : "", "syncSourceHost" : "", "syncSourceId" : -1, "heartbeatIntervalMillis" : NumberLong(2000), "optimes" : { "lastCommittedOpTime" : { "ts" : Timestamp(1537025984, 1), "t" : NumberLong(1) }, "readConcernMajorityOpTime" : { "ts" : Timestamp(1537025984, 1), "t" : NumberLong(1) }, "appliedOpTime" : { "ts" : Timestamp(1537025984, 1), "t" : NumberLong(1) }, "durableOpTime" : { "ts" : Timestamp(1537025984, 1), "t" : NumberLong(1) } }, "members" : [ { "_id" : 0, "name" : "192.168.195.137:27017", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", //此节点成为主节点 "uptime" : 1371, "optime" : { "ts" : Timestamp(1537025984, 1), "t" : NumberLong(1) }, .................... { "_id" : 1, "name" : "192.168.195.137:27018", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", //此节点为从节点 "uptime" : 18, "optime" : { "ts" : Timestamp(1537025984, 1), "t" : NumberLong(1) }, "optimeDurable" : { "ts" : Timestamp(1537025984, 1), "t" : NumberLong(1) }, ................... { "_id" : 2, "name" : "192.168.195.137:27019", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", //此节点为从节点 "uptime" : 18, "optime" : { "ts" : Timestamp(1537025984, 1), "t" : NumberLong(1) }, "optimeDurable" : { "ts" : Timestamp(1537025984, 1), "t" : NumberLong(1) }, 添加节点 true:PRIMARY> rs.add("192.168.195.137:27020") true:PRIMARY> rs.status() .............. { "_id" : 3, "name" : "192.168.195.137:27020", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 8, "optime" : { "ts" : Timestamp(1537026818, 1), "t" : NumberLong(1) }, "optimeDurable" : { "ts" : Timestamp(1537026818, 1), "t" : NumberLong(1) }, ................. 删除节点 true:PRIMARY> rs.remove("192.168.195.137:27020") 模拟故障自动转移切换 [root@localhost ~]# mongod -f /etc/mongod.conf --shutdown //关闭主节点服务 killing process with pid: 93576 [root@localhost ~]# mongo --port 27018 //进入其中一个从节点 MongoDB shell version v3.6.7 connecting to: mongodb://127.0.0.1:27018/ MongoDB server version: 3.6.7 true:PRIMARY> rs.status() //查看复制集信息 .............. }, "members" : [ { "_id" : 0, "name" : "192.168.195.137:27017", //原来的主节点健康值为0 "health" : 0, "state" : 8, "stateStr" : "(not reachable/healthy)", "uptime" : 0, "optime" : { "ts" : Timestamp(0, 0), "t" : NumberLong(-1) }, "optimeDurable" : { "ts" : Timestamp(0, 0), "t" : NumberLong(-1) }, ................. { "_id" : 1, "name" : "192.168.195.137:27018", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", //此节点切换成主节点 "uptime" : 2657, "optime" : { "ts" : Timestamp(1537027275, 1), "t" : NumberLong(2) }, ................ { "_id" : 2, "name" : "192.168.195.137:27019", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 1312, "optime" : { "ts" : Timestamp(1537027275, 1), "t" : NumberLong(2) }, "optimeDurable" : { "ts" : Timestamp(1537027275, 1), "t" : NumberLong(2) }, 手动进行主从切换 [root@localhost ~]# mongod -f /etc/mongod.conf #开启刚才关闭的端口为27017的节点实例 about to fork child process, waiting until server is ready for connections. forked process: 94723 child process started successfully, parent exiting [root@localhost ~]# mongo --port 27018 #进入主节点服务器实例 MongoDB shell version v3.6.7 connecting to: mongodb://127.0.0.1:27018/ MongoDB server version: 3.6.7 true:PRIMARY> rs.freeze(30) //暂停30s不参与选举 true:PRIMARY> rs.stepDown(60.30) //交出主节点位置，维持从节点状态不少于60秒，等待30秒使主节点和从节点日志同步 true:SECONDARY> rs.status() //可以看到本实例已经切换成从节点 ................ "members" : [ { "_id" : 0, "name" : "192.168.195.137:27017", // 端口27017的节点变成了主节点 "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "uptime" : 167, "optime" : { "ts" : Timestamp(1537027620, 1), "t" : NumberLong(3) }, "optimeDurable" : { "ts" : Timestamp(1537027620, 1), "t" : NumberLong(3) }, .................. { "_id" : 1, "name" : "192.168.195.137:27018", // 端口27018的节点变成了从节点 "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 2997, "optime" : { "ts" : Timestamp(1537027620, 1), "t" : NumberLong(3) }, ................... { "_id" : 2, "name" : "192.168.195.137:27019", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 1651, "optime" : { "ts" : Timestamp(1537027620, 1), "t" : NumberLong(3) }, "optimeDurable" : { "ts" : Timestamp(1537027620, 1), "t" : NumberLong(3) }, （编辑：聊城站长网） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |
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