副本集概述
副本集(Replica Set)是一组带有故障转移的 MongoDB 实例组成的集群,由一个主(Primary)服务器和多个从(Secondary)服务器构成。通过Replication,将数据的更新由Primary推送到其他实例上,在一定的延迟之后,每个MongoDB实例维护相同的数据集副本。通过维护冗余的数据库副本,能够实现数据的异地备份,读写分离和自动故障转移。
MongoDB 副本集中没有固定的主节点,在启动后,多个服务节点间将自动选举产生一个主节点。该主节点被称为primary,一个或多个从节点被称为secondaries。primary基本上就是master节点,不同之处在于primary节点在不同时间可能是不同的服务器。如果当前的主节点失效了,副本集中的其余节点将会试图选出一个新的主节点。
节点说明
MongoDB副本集架构通过部署多种节点来达到高可用和读写分离的效果,每个副本集实例包含一个主节点(Primary节点)、一个或多个从节点(Secondary节点)、隐藏节点(Hidden节点)、仲裁节点(Arbiter节点)和可选的一个或多个只读节点(ReadOnly节点)。其中主节点、从节点和隐藏节点合起来统称为“主备节点”。各节点的说明如下:
主节点(Primary节点)
- 负责执行和响应数据读写请求。每个副本集实例中只能有一个主节点。主节点将其数据集的所有更改记录在其操作日志(即oplog小于50 GB)中。
从节点(Secondary节点)
通过操作日志(oplog)同步主节点的数据,可在主节点故障时通过选举成为新的主节点,保障高可用。
通过从节点的连接地址进行连接时,只能读取数据不能写入数据。
从节点具有高可用保障,即某个从节点故障时,系统会自动将其与隐藏节点切换,若未自动切换,您可以自行切换,从节点的连接地址保持不变。
触发节点的角色切换后,会产生1次30秒内的连接闪断,建议您在业务低峰期操作或确保应用具备重连机制。
隐藏节点(Hidden节点)
通过操作日志(oplog)同步主节点的数据,可在从节点故障时接替该故障节点成为新的从节点,也可在只读节点故障时接替该故障节点成为新的只读节点,保障高可用。
隐藏节点仅用作高可用,对客户端不可见。
隐藏节点不在“主节点的备用列表”中,不会被选举为主节点,但会参与投票选举主节点。
每个副本集实例中只能有一个隐藏节点。
仲裁节点(Arbiter节点)
仲裁节点,只是用来投票,且投票的权重只能为1,不复制数据,也不能提升为primary。
仲裁节点常用于节点数量是偶数的副本集中。
通常将Arbiter部署在业务服务器上,切忌将其部署在Primary节点或Secondary节点服务器上。
只读节点(ReadOnly节点)
通过操作日志(oplog)从延迟最低的主节点或从节点同步数据,应用于有大量读请求的场景,以减轻主节点和从节点的访问压力。两个或以上只读节点可以使用ReadOnly Connection String URI连接实现读请求负载均衡。
只读节点具有高可用保障,即某个只读节点故障时,系统会自动将其与隐藏节点切换,若未自动切换,您可以自行切换,只读节点的连接地址保持不变。
触发节点的角色切换后,会产生1次30秒内的连接闪断,建议您在业务低峰期操作或确保应用具备重连机制。
只读节点具有独立的连接地址,适合独立系统直连访问,与已有主从节点的连接互不干扰。
只读节点不在“主节点的备用列表”中,不会被选举为主节点,也不会参与投票选举主节点。
副本集部署架构
MongoDB 6.x 官方介绍副本节点最少为3台,建议副本集成员为奇数,最多50个副本节点,最多7个节点参与选举。
限制副本节点的数量,主要是因为一个集群中过多的副本节点,增加了复制的成本,反而拖累了集群的整体性能。
太多的副本节点参与选举,也会增加选举的时间。而官方建议奇数的节点,是为了避免脑裂的发生。
副本集搭建过程环境准备
主机名 | IP地址 | 成员 |
---|---|---|
MongoDB-Master | 172.16.70.181 | 主节点 |
MongoDB-Slave01 | 172.16.70.182 | 从节点 |
MongoDB-Slave02 | 172.16.70.183 | 从节点 |
# 三个节点统一设置,这里以 MongoDB-Master 为例[root@MongoDB-Master ~]# cat /etc/redhat-releaseCentOS Linux release 7.9.2009 (Core)[root@MongoDB-Master ~]# uname -r3.10.0-1160.el7.x86_64# 修改ulimit 系统资源限制[root@MongoDB-Master ~]# cat /etc/security/limits.conf....末行追加以下内容....root soft nproc 65535root hard nproc 65535root hard nofile 65535root soft nofile 65535[root@MongoDB-Master ~]# setenforce 0[root@MongoDB-Master ~]# sed -i.bak '7s/enforcing/disabled/' /etc/selinux/config[root@MongoDB-Master ~]# systemctl stop firewalld[root@MongoDB-Master ~]# systemctl status firewalld● firewalld.service - firewalld - dynamic firewall daemon Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled) Active: inactive (dead) Docs: man:firewalld(1)
安装 MongoDB 6.0
# 使用Yum方式安装当前最新稳定版本,这里以 MongoDB-Master 为例,其他两从节点一样操作。[root@MongoDB-Master ~]# cat /etc/yum.repos.d/mongodb-org-6.0.repo[mongodb-org-6.0]name=MongoDB Repositorybaseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/6.0/x86_64/gpgcheck=1enabled=1gpgkey=https://www.mongodb.org/static/pgp/server-6.0.asc[root@MongoDB-Master ~]# yum install -y mongodb-org=========================================================================================================# 如要安装特定版本的 MongoDB,请单独指定每个组件包并将版本号附加到包名称,例如yum install -y mongodb-org-6.0.10 mongodb-org-database-6.0.10 mongodb-org-server-6.0.10 mongodb-org-mongos-6.0.10 mongodb-org-tools-6.0.10# yum当更新版本可用时升级软件包。为防止意外升级,请固定包。要固定包,请将以下exclude指令添加到您的/etc/yum.conf文件中exclude=mongodb-org,mongodb-org-database,mongodb-org-server,mongodb-mongosh,mongodb-org-mongos,mongodb-org-tools=========================================================================================================# 查看安装版本[root@MongoDB-Master ~]# mongod --versiondb version v6.0.11Build Info: { "version": "6.0.11", "gitVersion": "f797f841eaf1759c770271ae00c88b92b2766eed", "openSSLVersion": "OpenSSL 1.0.1e-fips 11 Feb 2013", "modules": [], "allocator": "tcmalloc", "environment": { "distmod": "rhel70", "distarch": "x86_64", "target_arch": "x86_64" }}# 修改配置文件 (bindIp: 127.0.0.1,172.16.70.181) [root@MongoDB-Master ~]# grep -Ev "^$" /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:# wiredTiger:# how the process runsprocessManagement: timeZoneInfo: /usr/share/zoneinfo# network interfacesnet: port: 27017 # 注意:本机的ip地址。否则后面进行副本集初始化的时候可能会失败! bindIp: 127.0.0.1,172.16.70.181 # Enter 0.0.0.0,:: to bind to all IPv4 and IPv6 addresses or, alternatively, use the net.bindIpAll setting.#security:#operationProfiling:replication: # 定义副本集名称 replSetName: testrs0#sharding:## Enterprise-Only Options#auditLog:#snmp:# 确保运行MongoDB的用户有权访问相关目录[root@MongoDB-Master ~]# grep mongo /etc/passwdmongod:x:997:996:mongod:/var/lib/mongo:/bin/false[root@MongoDB-Master ~]# ls -ld /var/log/mongodb/mongod.log /var/lib/mongodrwxr-xr-x 4 mongod mongod 4096 Oct 20 10:25 /var/lib/mongo-rw-r----- 1 mongod mongod 171974 Oct 20 10:22 /var/log/mongodb/mongod.log# 启动MongoDB[root@MongoDB-Master ~]# systemctl start mongod && systemctl enable mongod[root@MongoDB-Master ~]# systemctl list-units | grep mongodmongod.service loaded active running MongoDB Database Server[root@MongoDB-Master ~]# ps axu | grep mongodmongod 1563 1.8 2.4 2805700 97536 ? Ssl 11:26 0:01 /usr/bin/mongod -f /etc/mongod.confroot 1703 0.0 0.0 112808 968 pts/0 S+ 11:27 0:00 grep --color=auto mongod[root@MongoDB-Master ~]# netstat -ntpl | grep mongodtcp 0 0 172.16.70.181:27017 0.0.0.0:* LISTEN 1563/mongodtcp 0 0 127.0.0.1:27017 0.0.0.0:* LISTEN 1563/mongod[root@MongoDB-Master ~]# ls -l /tmp/mongodb-27017.socksrwx------ 1 mongod mongod 0 Oct 20 11:26 /tmp/mongodb-27017.sock
部署副本集
这里的_id
与配置文件mongod.conf中replSetName
保持一致。
# 在任意节点执行 rs.initiate,这里选择在MongoDB-Master操作初始化。[root@MongoDB-Master ~]# mongoshtest> rs.initiate( {... _id : "testrs0",... members: [... { _id: 0, host: "172.16.70.181:27017" },... { _id: 1, host: "172.16.70.182:27017" },... { _id: 2, host: "172.16.70.183:27017" }... ]... }){ ok: 1 }# 查看副本集配置,确保只有一个主节点testrs0 [direct: primary] test> rs.conf(){ _id: 'testrs0', version: 1, term: 1, members: [ { _id: 0, host: '172.16.70.181:27017', arbiterOnly: false, # 是否为仲裁者,默认为false buildIndexes: true, # 是否为构建索引成员 hidden: false, # 是否为隐藏成员 priority: 1, # 范围0~1000,默认为1,值大为主节点primary,值为0则不能成为primay(仲裁) tags: {}, secondaryDelaySecs: Long("0"), # 从节点复制延迟时间,单位秒s votes: 1 # 选举投票的数量 }, { _id: 1, host: '172.16.70.182:27017', arbiterOnly: false, buildIndexes: true, hidden: false, priority: 1, # 默认为1 tags: {}, secondaryDelaySecs: Long("0"), votes: 1 }, { _id: 2, host: '172.16.70.183:27017', arbiterOnly: false, buildIndexes: true, hidden: false, priority: 1, # 默认为1 tags: {}, secondaryDelaySecs: Long("0"), votes: 1 } ], protocolVersion: Long("1"), writeConcernMajorityJournalDefault: true, settings: { chainingAllowed: true, heartbeatIntervalMillis: 2000, heartbeatTimeoutSecs: 10, electionTimeoutMillis: 10000, catchUpTimeoutMillis: -1, catchUpTakeoverDelayMillis: 30000, getLastErrorModes: {}, getLastErrorDefaults: { w: 1, wtimeout: 0 }, replicaSetId: ObjectId("6531f7207c8f661d6f787810") }}testrs0 [direct: primary] test> rs.status(){ set: 'testrs0', # 副本集名称 date: ISODate("2023-10-20T04:06:56.352Z"), # 当前时间 myState: 1, # 成员的副本状态(0~10);常见 1:PRIMARY,2:SECONDARY,7:ARBITER,8:DOWN term: Long("2"), # 获得选举的票数 syncSourceHost: '', # 实例同步成员的主机名 syncSourceId: -1, # 实例同成员名称 heartbeatIntervalMillis: Long("2000"), # 心跳频率,毫秒ms majorityVoteCount: 2, # 被选举为主节点所需要的票数 writeMajorityCount: 2, # 满足写操作所需要的票数 votingMembersCount: 3, # 该副本集中成员数量 writableVotingMembersCount: 3, # 有投票权的成员数量 optimes: { lastCommittedOpTime: { ts: Timestamp({ t: 1697774807, i: 1 }), t: Long("2") }, lastCommittedWallTime: ISODate("2023-10-20T04:06:47.335Z"), readConcernMajorityOpTime: { ts: Timestamp({ t: 1697774807, i: 1 }), t: Long("2") }, appliedOpTime: { ts: Timestamp({ t: 1697774807, i: 1 }), t: Long("2") }, durableOpTime: { ts: Timestamp({ t: 1697774807, i: 1 }), t: Long("2") }, lastAppliedWallTime: ISODate("2023-10-20T04:06:47.335Z"), lastDurableWallTime: ISODate("2023-10-20T04:06:47.335Z") }, lastStableRecoveryTimestamp: Timestamp({ t: 1697774793, i: 1 }), electionCandidateMetrics: { lastElectionReason: 'stepUpRequestSkipDryRun', lastElectionDate: ISODate("2023-10-20T04:04:37.304Z"), electionTerm: Long("2"), lastCommittedOpTimeAtElection: { ts: Timestamp({ t: 1697774676, i: 1 }), t: Long("1") }, lastSeenOpTimeAtElection: { ts: Timestamp({ t: 1697774676, i: 1 }), t: Long("1") }, numVotesNeeded: 2, priorityAtElection: 1, electionTimeoutMillis: Long("10000"), priorPrimaryMemberId: 1, numCatchUpOps: Long("0"), newTermStartDate: ISODate("2023-10-20T04:04:37.311Z"), wMajorityWriteAvailabilityDate: ISODate("2023-10-20T04:04:38.331Z") }, electionParticipantMetrics: { votedForCandidate: true, electionTerm: Long("1"), lastVoteDate: ISODate("2023-10-20T03:42:36.120Z"), electionCandidateMemberId: 1, voteReason: '', lastAppliedOpTimeAtElection: { ts: Timestamp({ t: 1697773344, i: 1 }), t: Long("-1") }, maxAppliedOpTimeInSet: { ts: Timestamp({ t: 1697773344, i: 1 }), t: Long("-1") }, priorityAtElection: 1 }, members: [ { _id: 0, # 副本集中节点编号 name: '172.16.70.181:27017', # 服务器名称及端口号 health: 1, # 健康状态;1为正常,0为异常 state: 1, # 当前状态;数值小为primary,数值大为secondary stateStr: 'PRIMARY', # 主节点(PRIMARY),从节点(SECONDARY) uptime: 2424, # 在线时间(秒) optime: { ts: Timestamp({ t: 1697774807, i: 1 }), t: Long("2") }, # 最后一次应用日志(oplog)信息 optimeDate: ISODate("2023-10-20T04:06:47.000Z"), # 最后一次应用日志(oplog)时间 lastAppliedWallTime: ISODate("2023-10-20T04:06:47.335Z"), # 该成员在主节点上应用的最后一次操作的时间 lastDurableWallTime: ISODate("2023-10-20T04:06:47.335Z"), # 最后一次写入成员日志的操作首次在主节点上应用时的时间 syncSourceHost: '', syncSourceId: -1, infoMessage: '', electionTime: Timestamp({ t: 1697774677, i: 1 }), # primary从操作日志选举时间戳信息 electionDate: ISODate("2023-10-20T04:04:37.000Z"), # 被选定为primary的时间 configVersion: 1, # 副本集版本 configTerm: 2, self: true, lastHeartbeatMessage: '' }, { _id: 1, name: '172.16.70.182:27017', health: 1, state: 2, # 数值小为primary,数值大为secondary stateStr: 'SECONDARY', # 从节点 uptime: 84, optime: { ts: Timestamp({ t: 1697774807, i: 1 }), t: Long("2") }, optimeDurable: { ts: Timestamp({ t: 1697774807, i: 1 }), t: Long("2") }, optimeDate: ISODate("2023-10-20T04:06:47.000Z"), optimeDurableDate: ISODate("2023-10-20T04:06:47.000Z"), lastAppliedWallTime: ISODate("2023-10-20T04:06:47.335Z"), lastDurableWallTime: ISODate("2023-10-20T04:06:47.335Z"), lastHeartbeat: ISODate("2023-10-20T04:06:55.647Z"), lastHeartbeatRecv: ISODate("2023-10-20T04:06:55.575Z"), pingMs: Long("0"), lastHeartbeatMessage: '', syncSourceHost: '172.16.70.183:27017', syncSourceId: 2, infoMessage: '', configVersion: 1, configTerm: 2 }, { _id: 2, name: '172.16.70.183:27017', health: 1, state: 2, # 数值小为primary,数值大为secondary stateStr: 'SECONDARY', # 从节点 uptime: 1471, optime: { ts: Timestamp({ t: 1697774807, i: 1 }), t: Long("2") }, optimeDurable: { ts: Timestamp({ t: 1697774807, i: 1 }), t: Long("2") }, optimeDate: ISODate("2023-10-20T04:06:47.000Z"), optimeDurableDate: ISODate("2023-10-20T04:06:47.000Z"), lastAppliedWallTime: ISODate("2023-10-20T04:06:47.335Z"), lastDurableWallTime: ISODate("2023-10-20T04:06:47.335Z"), lastHeartbeat: ISODate("2023-10-20T04:06:55.561Z"), lastHeartbeatRecv: ISODate("2023-10-20T04:06:54.598Z"), pingMs: Long("0"), lastHeartbeatMessage: '', syncSourceHost: '172.16.70.181:27017', syncSourceId: 0, infoMessage: '', configVersion: 1, configTerm: 2 } ], ok: 1, '$clusterTime': { clusterTime: Timestamp({ t: 1697774807, i: 1 }), signature: { hash: Binary.createFromBase64("AAAAAAAAAAAAAAAAAAAAAAAAAAA=", 0), keyId: Long("0") } }, operationTime: Timestamp({ t: 1697774807, i: 1 })}testrs0 [direct: primary] test>
复制功能测试
# 在主节点(172.16.70.181)上新增mydb库,并创建myColl文档[root@MongoDB-Master ~]# mongoshtestrs0 [direct: primary] test>testrs0 [direct: primary] test> show dbsadmin 80.00 KiBconfig 208.00 KiBlocal 484.00 KiBtestrs0 [direct: primary] test> use mydbswitched to db mydbtestrs0 [direct: primary] mydb> db.myColl.insertOne({ name: "zhang" }){ acknowledged: true, insertedId: ObjectId("65361759be7d5c1abe9d83ee")}testrs0 [direct: primary] mydb> db.myColl.find()[ { _id: ObjectId("65361759be7d5c1abe9d83ee"), name: 'zhang' } ]# 在从节点(172.16.70.182/183)上查看复制同步数据结果[root@MongoDB-Slave01 ~]# mongoshtestrs0 [direct: secondary] test> use mydbswitched to db mydbtestrs0 [direct: secondary] mydb> show collectionsmyColltestrs0 [direct: secondary] mydb> db.myColl.find()MongoServerError: not primary and secondaryOk=false - consider using db.getMongo().setReadPref() or readPreference in the connection string# MongoServerError 报错!# 这是因为mongodb默认是从主节点读写数据的,副本节点上不允许读,需要设置副本节点可以读testrs0 [direct: secondary] mydb> db.getMongo().setReadPref('secondary')testrs0 [direct: secondary] mydb> db.myColl.find()[ { _id: ObjectId("65361759be7d5c1abe9d83ee"), name: 'zhang' } ]# 此时,主节点数据已经同步到从节点上
故障转移功能测试
# 假设主节点(172.16.70.181)故障[root@MongoDB-Master ~]# systemctl stop mongod[root@MongoDB-Master ~]# netstat -ntpl | grep mongod# 登录从节点查看副本集状态[root@MongoDB-Slave01 ~]# mongoshtestrs0 [direct: primary] test> rs.status(){ set: 'testrs0', date: ISODate("2023-10-23T07:55:53.369Z"), myState: 1, term: Long("2"), syncSourceHost: '', syncSourceId: -1, heartbeatIntervalMillis: Long("2000"), majorityVoteCount: 2, writeMajorityCount: 2, votingMembersCount: 3, writableVotingMembersCount: 3, optimes: { lastCommittedOpTime: { ts: Timestamp({ t: 1698047743, i: 1 }), t: Long("2") }, lastCommittedWallTime: ISODate("2023-10-23T07:55:43.519Z"), readConcernMajorityOpTime: { ts: Timestamp({ t: 1698047743, i: 1 }), t: Long("2") }, appliedOpTime: { ts: Timestamp({ t: 1698047743, i: 1 }), t: Long("2") }, durableOpTime: { ts: Timestamp({ t: 1698047743, i: 1 }), t: Long("2") }, lastAppliedWallTime: ISODate("2023-10-23T07:55:43.519Z"), lastDurableWallTime: ISODate("2023-10-23T07:55:43.519Z") }, lastStableRecoveryTimestamp: Timestamp({ t: 1698047693, i: 1 }), electionCandidateMetrics: { lastElectionReason: 'stepUpRequestSkipDryRun', lastElectionDate: ISODate("2023-10-23T07:51:13.449Z"), electionTerm: Long("2"), lastCommittedOpTimeAtElection: { ts: Timestamp({ t: 1698047468, i: 1 }), t: Long("1") }, lastSeenOpTimeAtElection: { ts: Timestamp({ t: 1698047468, i: 1 }), t: Long("1") }, numVotesNeeded: 2, priorityAtElection: 1, electionTimeoutMillis: Long("10000"), priorPrimaryMemberId: 0, numCatchUpOps: Long("0"), newTermStartDate: ISODate("2023-10-23T07:51:13.456Z"), wMajorityWriteAvailabilityDate: ISODate("2023-10-23T07:51:14.459Z") }, electionParticipantMetrics: { votedForCandidate: true, electionTerm: Long("1"), lastVoteDate: ISODate("2023-10-23T07:47:58.216Z"), electionCandidateMemberId: 0, voteReason: '', lastAppliedOpTimeAtElection: { ts: Timestamp({ t: 1698047267, i: 1 }), t: Long("-1") }, maxAppliedOpTimeInSet: { ts: Timestamp({ t: 1698047267, i: 1 }), t: Long("-1") }, priorityAtElection: 1 }, members: [ { _id: 0, name: '172.16.70.181:27017', health: 0, state: 8, stateStr: '(not reachable/healthy)', uptime: 0, optime: { ts: Timestamp({ t: 0, i: 0 }), t: Long("-1") }, optimeDurable: { ts: Timestamp({ t: 0, i: 0 }), t: Long("-1") }, optimeDate: ISODate("1970-01-01T00:00:00.000Z"), optimeDurableDate: ISODate("1970-01-01T00:00:00.000Z"), lastAppliedWallTime: ISODate("2023-10-23T07:51:14.906Z"), lastDurableWallTime: ISODate("2023-10-23T07:51:14.906Z"), lastHeartbeat: ISODate("2023-10-23T07:55:52.462Z"), lastHeartbeatRecv: ISODate("2023-10-23T07:51:28.493Z"), pingMs: Long("0"), lastHeartbeatMessage: 'Error connecting to 172.16.70.181:27017 :: caused by :: Connection refused', # 提示: Error syncSourceHost: '', syncSourceId: -1, infoMessage: '', configVersion: 1, configTerm: 2 }, { _id: 1, name: '172.16.70.182:27017', health: 1, state: 1, stateStr: 'PRIMARY', uptime: 1005, optime: { ts: Timestamp({ t: 1698047743, i: 1 }), t: Long("2") }, optimeDate: ISODate("2023-10-23T07:55:43.000Z"), lastAppliedWallTime: ISODate("2023-10-23T07:55:43.519Z"), lastDurableWallTime: ISODate("2023-10-23T07:55:43.519Z"), syncSourceHost: '', syncSourceId: -1, infoMessage: '', electionTime: Timestamp({ t: 1698047473, i: 1 }), electionDate: ISODate("2023-10-23T07:51:13.000Z"), configVersion: 1, configTerm: 2, self: true, lastHeartbeatMessage: '' }, { _id: 2, name: '172.16.70.183:27017', health: 1, state: 2, stateStr: 'SECONDARY', uptime: 486, optime: { ts: Timestamp({ t: 1698047743, i: 1 }), t: Long("2") }, optimeDurable: { ts: Timestamp({ t: 1698047743, i: 1 }), t: Long("2") }, optimeDate: ISODate("2023-10-23T07:55:43.000Z"), optimeDurableDate: ISODate("2023-10-23T07:55:43.000Z"), lastAppliedWallTime: ISODate("2023-10-23T07:55:43.519Z"), lastDurableWallTime: ISODate("2023-10-23T07:55:43.519Z"), lastHeartbeat: ISODate("2023-10-23T07:55:52.043Z"), lastHeartbeatRecv: ISODate("2023-10-23T07:55:52.568Z"), pingMs: Long("0"), lastHeartbeatMessage: '', syncSourceHost: '172.16.70.182:27017', syncSourceId: 1, infoMessage: '', configVersion: 1, configTerm: 2 } ], ok: 1, '$clusterTime': { clusterTime: Timestamp({ t: 1698047743, i: 1 }), signature: { hash: Binary.createFromBase64("AAAAAAAAAAAAAAAAAAAAAAAAAAA=", 0), keyId: Long("0") } }, operationTime: Timestamp({ t: 1698047743, i: 1 })}testrs0 [direct: primary] test># 此次,从节点(172.16.70.182)经过选举后,成为新的主节点。# 原主节点(172.16.70.181)故障恢复后,将成为新的主节点(172.16.70.182)的从节点。# 如果想实例预设成为主节点,可设置更高优先级priority(默认优先级为1,m值是0~1000之间的数字,数字越大优先级越高,m=0,则此节点永远不能成为主节点)# 即先移除rs.remove("ip:port"),再新增rs.add( { host: "ip:port", priority: Num } )
更改副本集优先级
# 查看当前副本集配置rs.conf()# n为 _id 值,从0开始为第一个节点,1为第二个节点,....# 默认优先级为1,m值是0~1000之间的数字,数字越大优先级越高,m=0,则此节点永远不能成为主节点(仲裁)cfg.members[n].priority = m# 重新配置当前副本集rs.reconfig(cfg)
新增副本集成员
# 必须在主节点上操作# 新增具有默认投票和优先级的成员到副本集rs.add( { host: "mongodbd4.example.net:27017" } )rs.add( "mongodbd4.example.net:27017" )# 新增优先级0的成员到副本集rs.add( { host: "mongodbd4.example.net:27017", priority: 0 } )# 新增仲裁者成员到副本集rs.add( { host: "mongodb3.example.net:27017", arbiterOnly: true } )rs.add("mongodb3.example.net:27017", true)
删除副本成员
rs.remove("mongod3.example.net:27017")rs.remove("mongod3.example.net")
替换副本集成员
cfg = rs.conf()cfg.members[0].host = "mongo2.example.net"rs.reconfig(cfg)
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作者:上古南城
出处:https://www.cnblogs.com/zhangwencheng
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