搭建mongodb集群（副本集+分片）

完整的搭建mongodb集群（副本集+分片）的例子。。。

准备四台机器，分别是bluejoe1,bluejoe2,bluejoe3，以及bluejoe0

副本集及分片策略确定如下：

将创建3个副本集，命名为shard1,shard2,shard3；
以上3个副本集作为3个分片；
每个副本集包含3个副本（主、辅1、辅2）；
副本分开存储，即shard1存在bluejoe1、bluejoe2、bluejoe3上各一份。。。以此类推
将创建3个配置库实例，一台机器一个
bluejoe0上配置一个mongos（mongos一般可以配置在应用端）

画了一个图：



具体操作步骤如下：

在bluejoe1上下载mongdb安装包；
解压至/usr/local/mongdb（注意改名）；
创建data/brick1,brick2,brick3目录，启动3个mongod实例，注意它们分别是shard1,shard2和shard3：

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/usr/local/mongodb/bin/mongod --dbpath /usr/local/mongodb/data/brick1 --port 10001 --replSet shard1 --logpath=/usr/local/mongodb/log/brick1.log

/usr/local/mongodb/bin/mongod --dbpath /usr/local/mongodb/data/brick2 --port 10002 --replSet shard2 --logpath=/usr/local/mongodb/log/brick2.log

/usr/local/mongodb/bin/mongod --dbpath /usr/local/mongodb/data/brick3 --port 10003 --replSet shard3 --logpath=/usr/local/mongodb/log/brick3.log

使用scp命令，将mongodb目录复制至bluejoe2和bluejoe3机器，并按照第3步启动每台机器上的3个实例；

初始化副本：

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mongo bluejoe1:10001



>use admin

>db.runCommand(

{

"replSetInitiate":

{

"_id":"shard1",

"members":

[

{

"_id":1,

"host":"bluejoe1:10001"

},

{

"_id":2,

"host":"bluejoe2:10003"

},

{

"_id":3,

"host":"bluejoe3:10002"

}

]

}

})



mongo bluejoe2:10001



>use admin

>db.runCommand(

{

"replSetInitiate":

{

"_id":"shard2",

"members":

[

{

"_id":1,

"host":"bluejoe2:10001"

},

{

"_id":2,

"host":"bluejoe1:10002"

},

{

"_id":3,

"host":"bluejoe3:10003"

}

]

}

})





mongo bluejoe3:10001

>use admin

>db.runCommand(

{

"replSetInitiate":

{

"_id":"shard3",

"members":

[

{

"_id":1,

"host":"bluejoe3:10001"

},

{

"_id":2,

"host":"bluejoe2:10002"

},

{

"_id":3,

"host":"bluejoe1:10003"

}

]

}

})

观察副本集的实时复制特性

连接上bluejoe1:10001，看到shard1:PRIMARY>的字样，说明它是shard1的主节点
创建一张新表，创建几条测试记录
连接上bluejoe3:10002，看到shard1:SECONDARY>的字样，说明它是shard1的辅助节点
注意此时无法查询前面新增的记录，会报错not master and slaveOk=false
回到bluejoe1:10001，设置slaveOk

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db.getMongo().setSlaveOk()

再回到bluejoe3:10002，即可看到主节点写入的记录

观察副本集的故障转移特性

杀掉bluejoe1:10001的进程
再次连接上bluejoe3:10002，看到shard1:PRIMARY>的字样，说明它已经变成shard1的主节点
如果这时再启动bluejoe1:10001，则发现它已经变成shard1:SECONDARY>

创建data/configdb，启动配置库实例：

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/usr/local/mongodb/bin/mongod --dbpath /usr/local/mongodb/data/configdb --port 20000 --logpath=/usr/local/mongodb/log/configdb.log

到现在为止应该有12个mongd实例，其中3个为配置库实例，剩下的属于3个副本集；
接下来管理分片，在bluejoe0上启动mongs：

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/usr/local/mongodb/bin/mongos --port 30000 --configdb bluejoe1:20000,bluejoe2:20000,bluejoe3:20000

连接上mongos，配置分片信息：

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mongos> use admin

switched to db admin



db.runCommand({"addShard":"shard1/bluejoe1:10001"})

db.runCommand({"addShard":"shard2/bluejoe2:10001"})

db.runCommand({"addShard":"shard3/bluejoe3:10001"})

查看分片情况：

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mongos> db.runCommand({listshards:1})

{

"shards" : [

{

"_id" : "shard1",

"host" : "shard1/bluejoe1:10001,bluejoe2:10003,bluejoe3:10002"

},

{

"_id" : "shard2",

"host" : "shard2/bluejoe1:10002,bluejoe2:10001,bluejoe3:10003"

},

{

"_id" : "shard3",

"host" : "shard3/bluejoe1:10003,bluejoe2:10002,bluejoe3:10001"

}

],

"ok" : 1

}

可以看出，尽管注册的时候只是提供了副本集的主节点，但mongos已知晓了各辅助节点；

对某个库开启分片功能：

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mongos> db.runCommand({"enablesharding":"test"})

{ "ok" : 1 }

mongos> db.runCommand({"shardcollection":"test.person","key":{_id:'hashed'}})

{ "collectionsharded" : "test.person", "ok" : 1 }

插入测试数据：

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mongos> for(var i=0;i<10;i++){db.person.insert({name:"bluejoe"+i});}

WriteResult({ "nInserted" : 1 })

查看数据分片存储情况：

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[root@hadoop0 ~]# mongo bluejoe3:10002

MongoDB shell version: 2.6.5

connecting to: bluejoe3:10002/test

shard1:PRIMARY> db.person.find()

{ "_id" : ObjectId("546ff1013a0d0ec68b42a914"), "name" : "bluejoe0" }

{ "_id" : ObjectId("546ff1013a0d0ec68b42a915"), "name" : "bluejoe1" }

{ "_id" : ObjectId("546ff1013a0d0ec68b42a91a"), "name" : "bluejoe6" }

{ "_id" : ObjectId("546ff1013a0d0ec68b42a91b"), "name" : "bluejoe7" }

{ "_id" : ObjectId("546ff1013a0d0ec68b42a91c"), "name" : "bluejoe8" }

shard1:PRIMARY> exit

bye

[root@hadoop0 ~]# mongo bluejoe2:10001

MongoDB shell version: 2.6.5

connecting to: bluejoe2:10001/test

shard2:PRIMARY> db.person.find()

{ "_id" : ObjectId("546ff1013a0d0ec68b42a918"), "name" : "bluejoe4" }

shard2:PRIMARY> exit

bye

[root@hadoop0 ~]# mongo bluejoe3:10001

MongoDB shell version: 2.6.5

connecting to: bluejoe3:10001/test

shard3:PRIMARY> db.person.find()

{ "_id" : ObjectId("546ff1013a0d0ec68b42a916"), "name" : "bluejoe2" }

{ "_id" : ObjectId("546ff1013a0d0ec68b42a917"), "name" : "bluejoe3" }

{ "_id" : ObjectId("546ff1013a0d0ec68b42a919"), "name" : "bluejoe5" }

{ "_id" : ObjectId("546ff1013a0d0ec68b42a91d"), "name" : "bluejoe9" }

shard3:PRIMARY>