MongoDB复制集——如何将单节点转换成复制集
具体步骤如下：
1. 停止单节点的mongod
我们可以从mongo shell里运行db.shutdownServer()命令来停止mongod
[java script] > use admin; switched to db admin > db.shutdownServer()
2. 使用--replSet的选项加上新的复制集的名字来重新启动这个mongod
[java script] bash-3.2$ mongod --dbpath /data/db --logpath /data/mongod.log --logappend --fork --port 30000 --replSet rs0 about to fork child process, waiting until server is ready for connections. forked process: 3092 all output going to: /data/mongod.log child process started successfully, parent exiting
3. 连接刚才启动的
数据库
[java script] bash-3.2$ mongo --port 30000 MongoDB shell version: 2.4.5 connecting to: 127.0.0.1:30000/test Server has startup warnings: Mon Jul 29 11:28:02.291 [initandlisten] Mon Jul 29 11:28:02.291 [initandlisten] ** WARNING: soft rlimits too low. Number of files is 256, should be at least 1000
4. 在mongo shell里创建一个包含复制集配置信息的对象
[java script]
rsconf = {
_id: "rs0",
members: [
{
_id: 0,
host: "localhost:30000"
}
]
}
5. 用rs.initiate()来初始化复制集
[java script]
> rs.initiate( rsconf )
{
"info" : "Config now saved locally. Should come online in about a minute.",
"ok" : 1
}
6. 初始化完毕后，我们可以用rs.conf()来查看复制集的配置
[java script]
> rs.conf()
{
"_id" : "rs0",
"version" : 1,
"members" : [
{
"_id" : 0,
"host" : "localhost:30000"
}
]
}
7. 我们还可以用rs.status()来查看复制集的运行状态
[java script]
rs0:PRIMARY> rs.status()
{
"set" : "rs0",
"date" : ISODate("2013-07-29T02:15:07Z"),
"myState" : 1,
"members" : [
{
"_id" : 0,
"name" : "localhost:30000",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 2185,
"optime" : Timestamp(1375062044, 1),
"optimeDate" : ISODate("2013-07-29T01:40:44Z"),
"self" : true
}
],
"ok" : 1
}
8. 启动一个新的mongod服务
[java script] bash-3.2$ mkdir -p /data/db2 bash-3.2$ mongod --dbpath /data/db2 --logpath /data/db2/mongod.log --logappend --fork --port 30001 --replSet rs0 about to fork child process, waiting until server is ready for connections. forked process: 3118 all output going to: /data/db2/mongod.log child process started successfully, parent exiting
9. 将新的mongod添加到复制集里
[java script]
rs0:PRIMARY> rs.add("localhost:30001")
{ "ok" : 1 }
10. 再启动一个新的mongod服务来作为仲裁节点
[java script] bash-3.2$ mkdir -p /data/arb bash-3.2$ mongod --dbpath /data/arb --logpath /data/arb/mongod.log --logappend --fork --port 30002 --replSet rs0 about to fork child process, waiting until server is ready for connections. forked process: 3124 all output going to: /data/arb/mongod.log child process started successfully, parent exiting
11. 将新启动的mongod服务作为仲裁节点添加到复制集中
[java script]
rs0:PRIMARY> rs.addArb("localhost:30002")
{ "ok" : 1 }
12. 查看复制集的状态
[java script]
rs0:PRIMARY> rs.status()
{
"set" : "rs0",
"date" : ISODate("2013-07-29T02:18:20Z"),
"myState" : 1,
"members" : [
{
"_id" : 0,
"name" : "localhost:30000",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 2378,
"optime" : Timestamp(1375064276, 1),
"optimeDate" : ISODate("2013-07-29T02:17:56Z"),
"self" : true
},
{
"_id" : 1,
"name" : "localhost:30001",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 34,
"opti