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-Master172.16.70.181主节点
MongoDB-Slave01172.16.70.182从节点
MongoDB-Slave02172.16.70.183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
版权:本文版权归作者和博客园共有,欢迎转载,但未经作者同意必须保留此段声明,且在文章页面明显位置给出 原文链接