MongoDB副本集--管理命令

这篇文档主要介绍MongoDB副本集的日常查看和管理的命令.

1)命令行的查看命令:db.serverCmdLineOpts()

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arps:SECONDARY> db.serverCmdLineOpts()
{
        "argv" : [
                "/opt/software/mongodb-linux-x86_64-3.0.1/bin/mongod",//启动参数mongod
                "-f",
                "/opt/software/mongodb-linux-x86_64-3.0.1/bin/mongodb.conf"  
        ],//参数配置文件
        "parsed" : {
                "config" : "/opt/software/mongodb-linux-x86_64-3.0.1/bin/mongodb.conf",
                "net" : {
                        "port" : 27017   //端口
                },
                "processManagement" : {
                        "fork" : true,
                        "pidFilePath" : "/opt/data/mongodb/mongodb.pid"  //进程文件
                },
                "replication" : {
                        "oplogSizeMB" : 10000,       //oplog日志大小
                        "replSet" : "arps"           //副本集的名称arps
                },
                "storage" : {
                        "dbPath" : "/opt/data/mongodb",   //数据存储的位置
                        "directoryPerDB" : true,
                        "mmapv1" : {
                                "preallocDataFiles" : false
                        }
                },
                "systemLog" : {
                        "destination" : "file",
                        "logAppend" : true,
                        "path" : "/opt/data/mongodb/log/mongodb.log"  //系统日志的位置
                }
        },
        "ok" : 1
}

2）查看副本集状态的命令：rs.status()

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arps:SECONDARY> rs.status()
{
        "set" : "arps",                                //副本集名称
        "date" : ISODate("2017-12-22T06:12:21.904Z"),  //执行时间
        "myState" : 2,                                
        "syncingTo" : "172.17.4.37:27017",             //同步源:172.17.4.37:27017
        "members" : [                                  //成员
                {
                        "_id" : 0,                    
                        "name" : "172.17.4.37:27017",
                        "health" : 1,                 //健康状态值，1为UP，0为down
                        "state" : 2,                  //成员状态值，2为secondary
                        "stateStr" : "SECONDARY",
                        "uptime" : 12354,
                        "optime" : Timestamp(1513923135, 3),  //最近一次更改数据库的时间。
                        "optimeDate" : ISODate("2017-12-22T06:12:15Z"),                                                   //最后一个操作发生的时间
                        "lastHeartbeat" : ISODate("2017-12-22T06:12:20.999Z"),                                                   //最后一次心跳接收的时间值
                        "lastHeartbeatRecv" : ISODate("2017-12-22T06:12:20.999Z"),                                                   //最近心跳的发送到达的时间值
                        "pingMs" : 0,
                        "syncingTo" : "172.17.4.38:27017",
                        "configVersion" : 1
                },
                {
                        "_id" : 1,
                        "name" : "172.17.4.38:27017",
                        "health" : 1,
                        "state" : 1,                  //成员状态值，1位primary
                        "stateStr" : "PRIMARY",
                        "uptime" : 12354,
                        "optime" : Timestamp(1513923135, 3),
                        "optimeDate" : ISODate("2017-12-22T06:12:15Z"),
                        "lastHeartbeat" : ISODate("2017-12-22T06:12:21.805Z"),
                        "lastHeartbeatRecv" : ISODate("2017-12-22T06:12:20.956Z"),
                        "pingMs" : 1,
                        "electionTime" : Timestamp(1506330005, 1),
                        "electionDate" : ISODate("2017-09-25T09:00:05Z"),
                        "configVersion" : 1
                },
                {
                        "_id" : 2,
                        "name" : "172.17.4.39:27017",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 12356,
                        "optime" : Timestamp(1513923135, 3),
                        "optimeDate" : ISODate("2017-12-22T06:12:15Z"),
                        "syncingTo" : "172.17.4.37:27017",
                        "configVersion" : 1,
                        "self" : true
                }
        ],
        "ok" : 1
}

mongod实例每隔两秒就会向其他成员发送一个心跳包，并且通过rs.status()中返回的成员的health来判断成员的状态。如果primary节点不可用了，那么复制集中的所有secondary节点都会触发一次选举操作。选出新的primary节点。如果secondary节点有多个，则会选举拥有最新oplog时间戳记录的或者有较高权限的节点成为primary

3）添加、删除副本集成员：rs.add，rs.addArb()，rs.remove()，rs.reconfig()

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1)添加成员 rs.add('172.17.4.39:27017')  //在添加成员之前，需要在目标成员里加上repset参数。
2)添加选举节点，不会同步数据
rs.add({,"host":"192.168.200.252:27017","arbiterOnly":true}) rs.addArb()
3）修改配置
通过rs.reconfig()来实现。
4）删除成员
rs.remove('172.17.4.39:27017')

4）副本集的配置：rs.config()

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arps:PRIMARY> rs.config()
{
        "_id" : "arps",
        "version" : 3,
        "members" : [
                {
                        "_id" : 0,
                        "host" : "172.17.4.37:27017",//主机名
                        "arbiterOnly" : false,       //是否为选举节点
                        "buildIndexes" : true,       //是否建立索引
                        "hidden" : false,            //是否隐藏
                        "priority" : 1,              //优先级
                        "tags" : {

                        },
                        "slaveDelay" : 0,
                        "votes" : 1                 
                },
                {
                        "_id" : 1,
                        "host" : "172.17.4.38:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 1,
                        "tags" : {

                        },
                        "slaveDelay" : 0,
                        "votes" : 1
                },
                {
                        "_id" : 2,
                        "host" : "172.17.4.39:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 1,
                        "tags" : {

                        },
                        "slaveDelay" : 0,
                        "votes" : 1
                }
        ],
        "settings" : {
                "chainingAllowed" : true,                  //自动寻找数据源功能
                "heartbeatTimeoutSecs" : 10,               //心跳连接超时时间
                "getLastErrorModes" : {                    

                },
                "getLastErrorDefaults" : {                //write concern写入安全机制
                        "w" : 1,                          //1为(应答时写入）                               //确认写入操作已经发送到指定的单个mongodb实例或者副本集的Primary
                        "wtimeout" : 0                   
                }
        }
}

5.Secondary进入维护模式：replSetMaintenance

如何让一个成员远落后于Primary的，进入维护模式

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arps:RECOVERING> db.adminCommand({"replSetMaintenance":true})   //进入维护模式

arps:RECOVERING> rs.status().members
[
        {
                "_id" : 0,
                "name" : "172.17.4.37:27017",
                "health" : 1,
                "state" : 2,
                "stateStr" : "SECONDARY",
                "uptime" : 15241,
                "optime" : Timestamp(1513926020, 4),
                "optimeDate" : ISODate("2017-12-22T07:00:20Z"),
                "lastHeartbeat" : ISODate("2017-12-22T07:00:28.772Z"),
                "lastHeartbeatRecv" : ISODate("2017-12-22T07:00:28.771Z"),
                "pingMs" : 0,
                "syncingTo" : "172.17.4.38:27017",
                "configVersion" : 3
        },
        {
                "_id" : 1,
                "name" : "172.17.4.38:27017",
                "health" : 1,
                "state" : 1,
                "stateStr" : "PRIMARY",
                "uptime" : 15241,
                "optime" : Timestamp(1513926020, 4),
                "optimeDate" : ISODate("2017-12-22T07:00:20Z"),
                "lastHeartbeat" : ISODate("2017-12-22T07:00:28.772Z"),
                "lastHeartbeatRecv" : ISODate("2017-12-22T07:00:26.849Z"),
                "pingMs" : 0,
                "electionTime" : Timestamp(1506330005, 1),
                "electionDate" : ISODate("2017-09-25T09:00:05Z"),
                "configVersion" : 3
        },
        {
                "_id" : 2,
                "name" : "172.17.4.39:27017",
                "health" : 1,
                "state" : 3,
                "stateStr" : "RECOVERING",   //进入维护模式，会强制进入RECOVERING状态，不提供服务
                "uptime" : 15243,
                "optime" : Timestamp(1513926020, 4),
                "optimeDate" : ISODate("2017-12-22T07:00:20Z"),
                "syncingTo" : "172.17.4.38:27017",
                "maintenanceMode" : 1,
                "configVersion" : 3,
                "self" : true
        }
]

arps:RECOVERING> db.adminCommand({"replSetMaintenance":false})  //退出维护模式

6.主节点变成备份节点：rs.stepDown(time)，rs.freeze(time)

rs.stepDown(time)  可以让主节点退成备份节点，timie单位是秒，默认60s。60s内主被副本集的其他成员获得，时间到后，会重新进行选举，一般都会重新成为主（优先级）。

rs.freeze(time)：阻止选举，始终出于备份节点状态。比如主节点需要做一些维护，不希望其他成员选举为主节点，可以在每个备份节点上执行。强制他们出于备份节点状态。

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arps:PRIMARY> rs.stepDown(30) //退出主节点，成为secondary节点
.......
.......
2017-12-22T15:05:52.110+0800 I NETWORK trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2017-12-22T15:05:52.111+0800 I NETWORK reconnect 127.0.0.1:27017 (127.0.0.1) ok
arps:SECONDARY>

arps:SECONDARY> rs.status().members
[
        {
                "_id" : 0,
                "name" : "172.17.4.37:27017",
                "health" : 1,
                "state" : 1,
                "stateStr" : "PRIMARY",  //升级为主节点
                "uptime" : 15797,
                "optime" : Timestamp(1513926601, 3),
                "optimeDate" : ISODate("2017-12-22T07:10:01Z"),
                "lastHeartbeat" : ISODate("2017-12-22T07:09:43.092Z"),
                "lastHeartbeatRecv" : ISODate("2017-12-22T07:09:43.130Z"),
                "pingMs" : 0,
                "electionTime" : Timestamp(1513926357, 1),
                "electionDate" : ISODate("2017-12-22T07:05:57Z"),
                "configVersion" : 3
        },
        {
                "_id" : 1,
                "name" : "172.17.4.38:27017",
                "health" : 1,
                "state" : 2,
                "stateStr" : "SECONDARY",  //退位至备份节点
                "uptime" : 15797,
                "optime" : Timestamp(1513926601, 3),
                "optimeDate" : ISODate("2017-12-22T07:10:01Z"),
                "lastHeartbeat" : ISODate("2017-12-22T07:09:43.092Z"),
                "lastHeartbeatRecv" : ISODate("2017-12-22T07:09:43.245Z"),
                "pingMs" : 0,
                "syncingTo" : "172.17.4.37:27017",
                "configVersion" : 3
        },
        {
                "_id" : 2,
                "name" : "172.17.4.39:27017",
                "health" : 1,
                "state" : 2,
                "stateStr" : "SECONDARY",
                "uptime" : 15799,
                "optime" : Timestamp(1513926601, 3),
                "optimeDate" : ISODate("2017-12-22T07:10:01Z"),
                "syncingTo" : "172.17.4.37:27017",
                "configVersion" : 3,
                "self" : true
        }
]

7.复制延迟状态查看db.printReplicationInfo()和db.printSlaveReplicationInfo()

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arps:PRIMARY> db.printReplicationInfo()    //主上面执行的复制状态信息
configured oplog size: 10000.003845214844MB
log length start to end: 31637996secs (8788.33hrs)
oplog first event time: Wed Dec 21 2016 10:54:05 GMT+0800 (CST)
oplog last event time: Fri Dec 22 2017 15:14:01 GMT+0800 (CST)
now: Fri Dec 22 2017 15:14:01 GMT+0800 (CST)

arps:SECONDARY> db.printSlaveReplicationInfo()  //从上面执行的复制延迟信息
source: 172.17.4.38:27017
        syncedTo: Fri Dec 22 2017 15:14:01 GMT+0800 (CST)
        0 secs (0 hrs) behind the primary
source: 172.17.4.39:27017
        syncedTo: Fri Dec 22 2017 15:14:01 GMT+0800 (CST)
        0 secs (0 hrs) behind the primary