mongoDB之Replica Set集群安装

Replica Set准确讲不完全是集群，只是一个主从复制的加强版

概念如下：

primary：主节点客户端写操作发生在这里。

secondary：副本，可以负载读操作，通过复制primary的oplog来实现数据同步

arbiter：仲裁节点，作用是当primary宕掉之后从secondarys选择一个变成primary

环境准备：

linux系统版本：

$ cat /proc/version
Linux version 2.6.32-358.el6.x86_64 (mockbuild@x86-022.build.eng.bos.redhat.com) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-3) (GCC) ) #1 SMP Tue Jan 29 11:47:41 EST 2013

三台服务器，详情如下：

192.168.38.17   --primary
192.168.38.18   --secondary
192.168.38.19   --arbiter

mongoDB版本：

mongodb-linux-x86_64-2.6.9

安装部署：

1.配置primary.conf，secondary.conf和arbiter.conf

#primary.conf：

#primary.conf
dbpath=/home/admin/data/p
logpath=/home/admin/log/primary.log
pidfilepath=/home/admin/data/primary.pid
directoryperdb=true
logappend=true
replSet=testrs
bind_ip=192.168.38.17
port=27017
oplogSize=10000
fork=true
noprealloc=true

#secondary.conf：

#secondary.conf
dbpath=/home/admin/data/s
logpath=/home/admin/log/secondary.log
pidfilepath=/home/admin/data/secondary.pid
directoryperdb=true
logappend=true
replSet=testrs
bind_ip=192.168.38.18
port=27017
oplogSize=10000
fork=true
noprealloc=true

#arbiter.conf：

dbpath=/home/admin/data/a
logpath=/home/admin/log/arbiter.log
pidfilepath/home/admin/data/arbiter.pid
directoryperdb=true
logappend=true
replSet=testrs
bind_ip=192.168.38.19
port=27017
oplogSize=10000
fork=true
noprealloc=true

上述配置文件最好在每个集群上都放置，这样就能保证配置文件一致

2.启动

分别在不同的节点上加载不同的配置

192.168.38.17启动：

bin/mongod -f /home/admin/mongodb/primary.conf

192.168.38.18启动：

bin/mongod -f /home/admin/mongodb/secondary.conf

192.168.38.19启动：

bin/mongod -f /home/admin/mongodb/arbiter.conf

3.登陆系统配置各个节点

bin/mongo 192.168.38.17:27017   

执行如下命令：

>use admin
>cfg={"_id": "testrs","members": [{"_id": 0,"host": "192.168.38.17:27017","priority": 2},{"_id": 1,"host": "192.168.38.18:27017","priority": 1},{"_id": 2,"host": "192.168.38.19:27017","arbiterOnly": true}]
}; 
>rs.initiate(cfg)  

此时配置已生效，可以通过命令查看相应的信息

4.查看目前各个节点的状态：

rs.status()

结果如下：

{"set" : "testrs","date" : ISODate("2015-04-03T09:02:29Z"),"myState" : 1,"members" : [{"_id" : 0,"name" : "192.168.38.17:27017","health" : 1,"state" : 1,"stateStr" : "PRIMARY","uptime" : 21104,"optime" : Timestamp(1428032802, 2),"optimeDate" : ISODate("2015-04-03T03:46:42Z"),"electionTime" : Timestamp(1428030689, 1),"electionDate" : ISODate("2015-04-03T03:11:29Z"),"self" : true},{"_id" : 1,"name" : "192.168.38.18:27017","health" : 1,"state" : 2,"stateStr" : "SECONDARY","uptime" : 21070,"optime" : Timestamp(1428032802, 2),"optimeDate" : ISODate("2015-04-03T03:46:42Z"),"lastHeartbeat" : ISODate("2015-04-03T09:02:27Z"),"lastHeartbeatRecv" : ISODate("2015-04-03T09:02:28Z"),"pingMs" : 0,"syncingTo" : "192.168.38.17:27017"},{"_id" : 2,"name" : "192.168.38.19:27017","health" : 1,"state" : 7,"stateStr" : "ARBITER","uptime" : 21070,"lastHeartbeat" : ISODate("2015-04-03T09:02:29Z"),"lastHeartbeatRecv" : ISODate("2015-04-03T09:02:29Z"),"pingMs" : 0}],"ok" : 1
}

此时配置已经完成，kill主节点之后查看状态会自动切换

PS：默认情况下副本是不会负载读操作的，如果打算让副本负载一部分读操作那么可以参见另外一篇博客