增加和减少mongodb复制集中的节点

MongoDB Replica Sets不仅提供高可用性的解决方案，同时也提供负载均衡的解决方案，增减 Replica Sets节点在实际应用中非常普通。例如，当应用的读压力暴增时，3台节点的环境已不能满足需求，那么就需要增加一些节点将压力平均分配一下；当应用的压力小时，可以减少一些节点来减少硬件资源的成本，总之这是一个长期且持续的工作。

增加节点步骤

1） 配置并启动新节点，启用 28013 这个端口给新的节点

[root@node222 mongodb]# mkdir -p /data02/mongors/data/r3

[root@node222 mongodb]# echo " this is rs1 super secret key " > /data02/mongors/key/r3

[root@node222 mongodb]# chmod 600 /data02/mongors/key/r3

[root@node222 mongodb]# /usr/local/mongodb/bin/mongod --replSet rs1 --keyFile /data02/mongors/key/r3 --fork --port 28013 --dbpath /data02/mongors/data/r3 --logpath=/data02/mongors/log/r3.log --logappend

about to fork child process, waiting until server is ready for connections.

forked process: 17718

child process started successfully, parent exiting

[root@node222 mongodb]#

2) 在primary节点上执行命令添加此新节点到现有的 Replica Sets

rs1:PRIMARY> rs.add("localhost:28013");rs.add("localhost:28013");

{ "ok" : 1 }

rs1:PRIMARY> rs.status();rs.status();

{

"set" : "rs1",

"date" : ISODate("2016-07-22T10:26:06.175Z"),

"myState" : 1,

"term" : NumberLong(2),

"heartbeatIntervalMillis" : NumberLong(2000),

"members" : [

{

"_id" : 0,

"name" : "localhost:28010",

"health" : 1,

"state" : 2,

"stateStr" : "SECONDARY",

"uptime" : 235,

"optime" : {

"ts" : Timestamp(1469183031, 1),

"t" : NumberLong(2)

},

"optimeDate" : ISODate("2016-07-22T10:23:51Z"),

"lastHeartbeat" : ISODate("2016-07-22T10:26:05.493Z"),

"lastHeartbeatRecv" : ISODate("2016-07-22T10:26:05.603Z"),

"pingMs" : NumberLong(0),

"syncingTo" : "localhost:28012",

"configVersion" : 2

},

{

"_id" : 1,

"name" : "localhost:28011",

"health" : 1,

"state" : 2,

"stateStr" : "SECONDARY",

"uptime" : 2749,

"optime" : {

"ts" : Timestamp(1469183031, 1),

"t" : NumberLong(2)

},

"optimeDate" : ISODate("2016-07-22T10:23:51Z"),

"lastHeartbeat" : ISODate("2016-07-22T10:26:05.493Z"),

"lastHeartbeatRecv" : ISODate("2016-07-22T10:26:05.603Z"),

"pingMs" : NumberLong(0),

"syncingTo" : "localhost:28012",

"configVersion" : 2

},

{

"_id" : 2,

"name" : "localhost:28012",

"health" : 1,

"state" : 1,

"stateStr" : "PRIMARY",

"uptime" : 2956,

"optime" : {

"ts" : Timestamp(1469183031, 1),

"t" : NumberLong(2)

},

"optimeDate" : ISODate("2016-07-22T10:23:51Z"),

"electionTime" : Timestamp(1469182400, 1),

"electionDate" : ISODate("2016-07-22T10:13:20Z"),

"configVersion" : 2,

"self" : true

},

{

"_id" : 3,

"name" : "localhost:28013",

"health" : 1,

"state" : 2,

"stateStr" : "SECONDARY",

"uptime" : 65,

"optime" : {

"ts" : Timestamp(1469177570, 1),

"t" : NumberLong(1)

},

"optimeDate" : ISODate("2016-07-22T08:52:50Z"),

"lastHeartbeat" : ISODate("2016-07-22T08:53:54.701Z"),

"lastHeartbeatRecv" : ISODate("2016-07-22T08:53:51.755Z"),

"pingMs" : NumberLong(0),

"configVersion" : 2

}

],

"ok" : 1

}

rs1:PRIMARY> rs.config();rs.config();

{

"_id" : "rs1",

"version" : 2,

"protocolVersion" : NumberLong(1),

"members" : [

{

"_id" : 0,

"host" : "localhost:28010",

"arbiterOnly" : false,

"buildIndexes" : true,

"hidden" : false,

"priority" : 1,

"tags" : {

},

"slaveDelay" : NumberLong(0),

"votes" : 1

},

{

"_id" : 1,

"host" : "localhost:28011",

"arbiterOnly" : false,

"buildIndexes" : true,

"hidden" : false,

"priority" : 1,

"tags" : {

},

"slaveDelay" : NumberLong(0),

"votes" : 1

},

{

"_id" : 2,

"host" : "localhost:28012",

"arbiterOnly" : false,

"buildIndexes" : true,

"hidden" : false,

"priority" : 1,

"tags" : {

},

"slaveDelay" : NumberLong(0),

"votes" : 1

},

{

"_id" : 3,

"host" : "localhost:28013",

"arbiterOnly" : false,

"buildIndexes" : true,

"hidden" : false,

"priority" : 1,

"tags" : {

},

"slaveDelay" : NumberLong(0),

"votes" : 1

}

],

"settings" : {

"chainingAllowed" : true,

"heartbeatIntervalMillis" : 2000,

"heartbeatTimeoutSecs" : 10,

"electionTimeoutMillis" : 10000,

"getLastErrorModes" : {

},

"getLastErrorDefaults" : {

"w" : 1,

"wtimeout" : 0

},

"replicaSetId" : ObjectId("5791ea00a9dbf7228bb1ec0c")

}

}

rs1:PRIMARY>

3）验证数据是否已经同步过来了

# /usr/local/mongodb/bin/mongo -port 28013

> rs.slaveOK()

> db.c1.find()

删除节点步骤

下面将刚刚添加的两个新节点 28013 从复制集中去除掉，只需 rs.remove 指令就可以了，具体如下：

登录到primary 节点，执行下面的命令将28013 从复制集中去掉：

> rs.remove("localhsots:28013");

查看复制集状态，可以看到只有三个成员，原来的两个成员都已经成功去除了：

> rs.status()

rs1:PRIMARY> rs.remove("localhost:28013");rs.remove("localhost:28013");

{ "ok" : 1 }

rs1:PRIMARY> rs.conf() rs.conf()

{

"_id" : "rs1",

"version" : 3,

"protocolVersion" : NumberLong(1),

"members" : [

{

"_id" : 0,

"host" : "localhost:28010",

"arbiterOnly" : false,

"buildIndexes" : true,

"hidden" : false,

"priority" : 1,

"tags" : {

},

"slaveDelay" : NumberLong(0),

"votes" : 1

},

{

"_id" : 1,

"host" : "localhost:28011",

"arbiterOnly" : false,

"buildIndexes" : true,

"hidden" : false,

"priority" : 1,

"tags" : {

},

"slaveDelay" : NumberLong(0),

"votes" : 1

},

{

"_id" : 2,

"host" : "localhost:28012",

"arbiterOnly" : false,

"buildIndexes" : true,

"hidden" : false,

"priority" : 1,

"tags" : {

},

"slaveDelay" : NumberLong(0),

"votes" : 1

}

],

"settings" : {

"chainingAllowed" : true,

"heartbeatIntervalMillis" : 2000,

"heartbeatTimeoutSecs" : 10,

"electionTimeoutMillis" : 10000,

"getLastErrorModes" : {

},

"getLastErrorDefaults" : {

"w" : 1,

"wtimeout" : 0

},

"replicaSetId" : ObjectId("5791d785947160a5bdbd700b")

}

}

rs1:PRIMARY>