MongoDB副本集

MongoDB提供两种复制风格：主从复制、副本集

两种方式都是在一个主节点进行写操作（写入的数据被异步地同步到所有的从节点），并从节点上读取数据。
副本集保证自动故障转移，如果主节点由于某种原因下线，可能的花，会自动将一哥从节点提升为主节点。
只有一种情况需要选择MongoDB的主从复制，即需要超过11个从节点时，因为副本集不能包含12个以上的成员。

为副本集的每个成员创建数据目录：
[root@vhost2 ~]# mkdir -p /data/mongo1
[root@vhost2 ~]# mkdir -p /data/mongo2
[root@vhost2 ~]# mkdir -p /data/mongo3
启动mongod
[root@vhost2 ~]# mongod --replSet myapp --dbpath /data/mongo1 --port 40001 &
[root@vhost2 ~]# mongod --replSet myapp --dbpath /data/mongo2 --port 40002 &
[root@vhost2 ~]# mongod --replSet myapp --dbpath /data/mongo3 --port 40003 &
配置副本集，先连接到一个刚启动的非冲裁节点的mongod上,
[root@vhost2 ~]# mongo 127.0.0.1:40001/admin

MongoDB Enterprise > rs.initiate()
{
"info2" : "no configuration specified. Using a default configuration for the set",
"me" : "vhost2:40001",
"ok" : 1
}
MongoDB Enterprise myapp:OTHER>
1分钟之后，配置了拥有一个单成员的副本集，通过rs.add()添加其他两个成员：
MongoDB Enterprise myapp:PRIMARY> rs.add("vhost2:40002")
{ "ok" : 1 }
MongoDB Enterprise myapp:PRIMARY> rs.add("vhost2.local:40003",{arbiterOnly:true})
{ "ok" : 1 }
#arbiterOnly,创建仲裁节点，1分钟之后，所有成员都在线
db.isMaster():获取副本集状态的摘要信息

MongoDB Enterprise myapp:PRIMARY> db.isMaster()

{
    "hosts" : [
        "vhost2:40001",
        "vhost2:40002"
    ],
    "arbiters" : [
        "vhost2:40003"
    ],
    "setName" : "myapp",
    "setVersion" : 5,
    "ismaster" : true,
    "secondary" : false,
    "primary" : "vhost2:40001",
    "me" : "vhost2:40001",
    "electionId" : ObjectId("7fffffff0000000000000001"),
    "lastWrite" : {
        "opTime" : {
            "ts" : Timestamp(1512824958, 1),
            "t" : NumberLong(1)
        },
        "lastWriteDate" : ISODate("2017-12-09T13:09:18Z")
    },
    "maxBsonObjectSize" : 16777216,
    "maxMessageSizeBytes" : 48000000,
    "maxWriteBatchSize" : 1000,
    "localTime" : ISODate("2017-12-09T13:09:24.062Z"),
    "maxWireVersion" : 5,
    "minWireVersion" : 0,
    "readOnly" : false,
    "ok" : 1
}

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#rs.status()提供详细的系统信息，除非MongoDB数据库中包含数据量比较大，否则副本集能在30s内上线，在此期间，每个节点的
statStr字段应该会从RECOVERING变为PRIMARY,SECONDARY或ARBITER。

rs.status() 查看副本集主从节点的状态
MongoDB Enterprise myapp:PRIMARY> rs.status()

{
    "set" : "myapp",
    "date" : ISODate("2017-12-09T13:08:41.030Z"),
    "myState" : 1,
    "term" : NumberLong(1),
    "heartbeatIntervalMillis" : NumberLong(2000),
    "optimes" : {
        "lastCommittedOpTime" : {
            "ts" : Timestamp(1512824918, 1),
            "t" : NumberLong(1)
        },
        "appliedOpTime" : {
            "ts" : Timestamp(1512824918, 1),
            "t" : NumberLong(1)
        },
        "durableOpTime" : {
            "ts" : Timestamp(1512824918, 1),
            "t" : NumberLong(1)
        }
    },
    "members" : [
        {
            "_id" : 0,
            "name" : "vhost2:40001",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 4026,
            "optime" : {
                "ts" : Timestamp(1512824918, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2017-12-09T13:08:38Z"),
            "electionTime" : Timestamp(1512820966, 2),
            "electionDate" : ISODate("2017-12-09T12:02:46Z"),
            "configVersion" : 5,
            "self" : true
        },
        {
            "_id" : 1,
            "name" : "vhost2:40002",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 3501,
            "optime" : {
                "ts" : Timestamp(1512824918, 1),
                "t" : NumberLong(1)
            },
            "optimeDurable" : {
                "ts" : Timestamp(1512824918, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2017-12-09T13:08:38Z"),
            "optimeDurableDate" : ISODate("2017-12-09T13:08:38Z"),
            "lastHeartbeat" : ISODate("2017-12-09T13:08:39.445Z"),
            "lastHeartbeatRecv" : ISODate("2017-12-09T13:08:40.483Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "vhost2:40001",
            "configVersion" : 5
        },
        {
            "_id" : 2,
            "name" : "vhost2:40003",
            "health" : 1,
            "state" : 7,
            "stateStr" : "ARBITER",
            "uptime" : 2942,
            "lastHeartbeat" : ISODate("2017-12-09T13:08:40.900Z"),
            "lastHeartbeatRecv" : ISODate("2017-12-09T13:08:39.725Z"),
            "pingMs" : NumberLong(0),
            "configVersion" : 5
        }
    ],
    "ok" : 1
}

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"health" : 1, #1 表明正常; 0 表明异常
"state" : 1, # 1 表明是Primary; 2 表明是Secondary;
"stateStr" : "PRIMARY", #表明此机器是主库

MongoDB Enterprise myapp:PRIMARY>
主节点插入数据
[root@vhost2 ~]# mongo vhost2:40001/admin
MongoDB Enterprise myapp:PRIMARY> use bookstore;
switched to db bookstore
MongoDB Enterprise myapp:PRIMARY> db.books.insert({title:"Oliver Twist"})
WriteResult({ "nInserted" : 1 })
MongoDB Enterprise myapp:PRIMARY> show dbs;
admin 0.000GB
bookstore 0.000GB
local 0.000GB
MongoDB Enterprise myapp:PRIMARY> db.books.find()
{ "_id" : ObjectId("5a2be17a65e2395a10373f77"), "title" : "Oliver Twist" }
从节点：
[root@vhost2 ~]# mongo vhost2:40002
MongoDB Enterprise myapp:SECONDARY> show dbs;
2017-12-09T08:16:59.482-0500 E QUERY [thread1] Error: listDatabases failed:{
"ok" : 0,
"errmsg" : "not master and slaveOk=false",
"code" : 13435,
"codeName" : "NotMasterNoSlaveOk"
} :
_getErrorWithCode@src/mongo/shell/utils.js:25:13
Mongo.prototype.getDBs@src/mongo/shell/mongo.js:62:1
shellHelper.show@src/mongo/shell/utils.js:781:19
shellHelper@src/mongo/shell/utils.js:671:15
@(shellhelp2):1:1
MongoDB Enterprise myapp:SECONDARY>
SECONDARY是不允许读写的，如果非要解决，方法如下：
rs.slaveOk();
MongoDB Enterprise myapp:SECONDARY> rs.slaveOk();
MongoDB Enterprise myapp:SECONDARY> show dbs;
admin 0.000GB
bookstore 0.000GB
local 0.000GB
MongoDB Enterprise myapp:SECONDARY> use bookstore
switched to db bookstore
MongoDB Enterprise myapp:SECONDARY> db.books.find()
{ "_id" : ObjectId("5a2be17a65e2395a10373f77"), "title" : "Oliver Twist" }
冲裁节点：
[root@vhost2 ~]# mongo vhost2:40003
MongoDB Enterprise myapp:ARBITER> rs.slaveOk();
MongoDB Enterprise myapp:ARBITER> show dbs;
local 0.000GB
切换：关闭主节点，CTRL-C、kill -2 或在SHELL中运行db.shutdownServer()
[root@vhost2 ~]# kill -2 26036
[root@vhost2 ~]# mongo vhost2:40002
MongoDB Enterprise myapp:PRIMARY> show dbs;
admin 0.000GB
bookstore 0.000GB
local 0.000GB
MongoDB Enterprise myapp:PRIMARY> rs.status()

{
    "set" : "myapp",
    "date" : ISODate("2017-12-09T14:22:06.153Z"),
    "myState" : 1,
    "term" : NumberLong(2),
    "heartbeatIntervalMillis" : NumberLong(2000),
    "optimes" : {
        "lastCommittedOpTime" : {
            "ts" : Timestamp(1512829209, 1),
            "t" : NumberLong(1)
        },
        "appliedOpTime" : {
            "ts" : Timestamp(1512829322, 1),
            "t" : NumberLong(2)
        },
        "durableOpTime" : {
            "ts" : Timestamp(1512829322, 1),
            "t" : NumberLong(2)
        }
    },
    "members" : [
        {
            "_id" : 0,
            "name" : "vhost2:40001",
            "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)
            },
            "optimeDate" : ISODate("1970-01-01T00:00:00Z"),
            "optimeDurableDate" : ISODate("1970-01-01T00:00:00Z"),
            "lastHeartbeat" : ISODate("2017-12-09T14:22:04.668Z"),
            "lastHeartbeatRecv" : ISODate("2017-12-09T14:20:08.573Z"),
            "pingMs" : NumberLong(0),
            "lastHeartbeatMessage" : "Connection refused",
            "configVersion" : -1
        },
        {
            "_id" : 1,
            "name" : "vhost2:40002",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 8409,
            "optime" : {
                "ts" : Timestamp(1512829322, 1),
                "t" : NumberLong(2)
            },
            "optimeDate" : ISODate("2017-12-09T14:22:02Z"),
            "infoMessage" : "could not find member to sync from",
            "electionTime" : Timestamp(1512829220, 1),
            "electionDate" : ISODate("2017-12-09T14:20:20Z"),
            "configVersion" : 5,
            "self" : true
        },
        {
            "_id" : 2,
            "name" : "vhost2:40003",
            "health" : 1,
            "state" : 7,
            "stateStr" : "ARBITER",
            "uptime" : 7304,
            "lastHeartbeat" : ISODate("2017-12-09T14:22:04.428Z"),
            "lastHeartbeatRecv" : ISODate("2017-12-09T14:22:05.986Z"),
            "pingMs" : NumberLong(0),
            "configVersion" : 5
        }
    ],
    "ok" : 1
}
MongoDB Enterprise myapp:PRIMARY>

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故障转移后，副本集就只有两个节点，仲裁节点没有数据。假设旧的主节点正常关闭，启动该节点，
它将以从节点的身份重新键入副本集：
重启主节点：
[root@vhost2 ~]# mongo vhost2:40001/admin
MongoDB Enterprise myapp:SECONDARY> show dbs;
2017-12-09T09:24:34.262-0500 E QUERY [thread1] Error: listDatabases failed:{
"ok" : 0,
"errmsg" : "not master and slaveOk=false",
"code" : 13435,
"codeName" : "NotMasterNoSlaveOk"
} :
_getErrorWithCode@src/mongo/shell/utils.js:25:13
Mongo.prototype.getDBs@src/mongo/shell/mongo.js:62:1
shellHelper.show@src/mongo/shell/utils.js:781:19
shellHelper@src/mongo/shell/utils.js:671:15
@(shellhelp2):1:1
MongoDB Enterprise myapp:SECONDARY> rs.slaveOk()
MongoDB Enterprise myapp:SECONDARY> show dbs;
admin 0.000GB
bookstore 0.000GB
local 0.000GB
MongoDB Enterprise myapp:SECONDARY> rs.st
rs.status( rs.stepDown(
MongoDB Enterprise myapp:SECONDARY> rs.status()
{
"set" : "myapp",
"date" : ISODate("2017-12-09T14:24:47.063Z"),
"myState" : 2,
"term" : NumberLong(2),
"syncingTo" : "vhost2:40002",
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1512829482, 1),
"t" : NumberLong(2)
},
"appliedOpTime" : {
"ts" : Timestamp(1512829482, 1),
"t" : NumberLong(2)
},
"durableOpTime" : {
"ts" : Timestamp(1512829482, 1),
"t" : NumberLong(2)
}
},
"members" : [
{
"_id" : 0,
"name" : "vhost2:40001",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 77,
"optime" : {
"ts" : Timestamp(1512829482, 1),
"t" : NumberLong(2)
},
"optimeDate" : ISODate("2017-12-09T14:24:42Z"),
"syncingTo" : "vhost2:40002",
"configVersion" : 5,
"self" : true
},
{
"_id" : 1,
"name" : "vhost2:40002",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 63,
"optime" : {
"ts" : Timestamp(1512829482, 1),
"t" : NumberLong(2)
},
"optimeDurable" : {
"ts" : Timestamp(1512829482, 1),
"t" : NumberLong(2)
},
"optimeDate" : ISODate("2017-12-09T14:24:42Z"),
"optimeDurableDate" : ISODate("2017-12-09T14:24:42Z"),
"lastHeartbeat" : ISODate("2017-12-09T14:24:45.594Z"),
"lastHeartbeatRecv" : ISODate("2017-12-09T14:24:47.010Z"),
"pingMs" : NumberLong(0),
"electionTime" : Timestamp(1512829220, 1),
"electionDate" : ISODate("2017-12-09T14:20:20Z"),
"configVersion" : 5
},
{
"_id" : 2,
"name" : "vhost2:40003",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER",
"uptime" : 63,
"lastHeartbeat" : ISODate("2017-12-09T14:24:45.598Z"),
"lastHeartbeatRecv" : ISODate("2017-12-09T14:24:46.216Z"),
"pingMs" : NumberLong(0),
"configVersion" : 5
}
],
"ok" : 1
}
MongoDB Enterprise myapp:SECONDARY>

https://www.cnblogs.com/wadeyu/p/7930608.html

posted on 2018-04-19 18:39 HelonTian 阅读(190) 评论(0) 编辑收藏举报