mongodb副本集群搭建
1、启动replSet模式
（1）修改monodb.conf （所有节点均加入）
replSet=k01 #加入参数，k01为副本集名称#
（2）启动mongod是加入参数 --replSet {副本集名称}
2、初始化副本集 #只能初始化一次，从库只保持能连通状态即可#
> rs.initiate({"_id":"k01","members":[
{"_id":1,
"host":"10.120.126.122:27017",
"priority":1
},
{"_id":2,
"host":"10.120.126.123:27017",
"priority":1
}
]})
"_id": 副本集的名称
"members": 副本集的服务器列表
"_id": 服务器的唯一ID
"host": 服务器主机
"priority": 是优先级，默认为1，优先级0为被动节点，不能成为活跃节点。优先级不位0则按照有大到小选出活跃节点。
"arbiterOnly": 仲裁节点，只参与投票，不接收数据，也不能成为活跃节点。
k01:PRIMARY> rs.status() #查看副本集状态#
{
"set" : "k01",
"date" : ISODate("2018-09-25T09:08:06.039Z"),
"myState" : 1,
"term" : NumberLong(1),
"heartbeatIntervalMillis" : NumberLong(2000),
"members" : [
{
"_id" : 1,
"name" : "10.120.126.122:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 2636,
"optime" : {
"ts" : Timestamp(1537864674, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2018-09-25T08:37:54Z"),
"electionTime" : Timestamp(1537864018, 1),
"electionDate" : ISODate("2018-09-25T08:26:58Z"),
"configVersion" : 1,
"self" : true
},
{
"_id" : 2,
"name" : "10.120.126.123:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 2478,
"optime" : {
"ts" : Timestamp(1537864674, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2018-09-25T08:37:54Z"),
"lastHeartbeat" : ISODate("2018-09-25T09:08:04.418Z"),
"lastHeartbeatRecv" : ISODate("2018-09-25T09:08:05.853Z"),
"pingMs" : NumberLong(0),
"syncingTo" : "10.120.126.122:27017",
"configVersion" : 1
}
],
"ok" : 1
}
k01:SECONDARY> rs.slaveOk(); #可使从库从不可读写状态变成只读状态#
k01:PRIMARY> rs.add() #添加节点#
k01:SECONDARY> rs.isMaster()
{
"hosts" : [
"10.120.126.122:27017",
"10.120.126.123:27017"
],
"setName" : "k01",
"setVersion" : 1,
"ismaster" : false,
"secondary" : true,
"primary" : "10.120.126.122:27017",
"me" : "10.120.126.123:27017",
"maxBsonObjectSize" : 16777216,
"maxMessageSizeBytes" : 48000000,
"maxWriteBatchSize" : 1000,
"localTime" : ISODate("2018-09-25T08:44:48.708Z"),
"maxWireVersion" : 4,
"minWireVersion" : 0,
"ok" : 1
}