MongoDB副本集
一、节点类型
standard：常规节点，它存储一份完整的数据副本，参与选举投票，有可能成为活跃节点。
passive：存储了完整的数据副本，参与投票，不能成为活跃节点。
arbiter：仲裁节点，只参与投票，不接收复制的数据，也不能成为活跃节点。
二、参数说明
--dbpath 数据文件路径
--logpath 日志文件路径
--port 端口号，默认是27017.我这里使用的也是这个端口号.
--replSet 复制集的名字，一个replica sets中的每个节点的这个参数都要用一个复制集名字，这里是test.
--replSet 这个后面跟的是其他standard节点的ip和端口
--maxConns 最大连接数
--fork 后台运行
--logappend 日志文件循环使用，如果日志文件已满，那么新日志覆盖最久日志。
三、创建副本集
环境说明:
ip:10.0.0.3 ip:10.0.0.4 ip:10.0.0.5
启动第一个standard节点（ip:10.0.0.3)
hww@ubuntu:~$ mkdir -p ~/mongo/db ~/mongo/log hww@ubuntu:~$ mongod -dbpath ~/mongo/db -logpath ~/mongo/log/mongod.log -port 27037 -replSet test -maxConns=2000 -fork -logappend
启动第一个standard节点（ip:10.0.0.4)
hww@ubuntu:~$ mkdir -p ~/mongo/db ~/mongo/log hww@ubuntu:~$ mongod -dbpath ~/mongo/db -logpath ~/mongo/log/mongod.log -port 27037 -replSet test -maxConns=2000 -fork -logappend
启动arbiter节点，也就是仲裁节点 （ip:10.0.0.5)
hww@ubuntu:~$ mkdir -p ~/mongo/db ~/mongo/log hww@ubuntu:~$ mongod -dbpath ~/mongo/db -logpath ~/mongo/log/mongod.log -port 27037 -replSet test -maxConns=2000 -fork -logappend
启动了以上服务器后，日志告诉你副本集没有初始化。因为还差最后一步：在shell中初始化副本集。
连接其中一台standard节点服务器。初始化命令只能执行一次 ：
hww@ubuntu:~$ mongo 10.0.0.3:27037/admin
MongoDB shell version: 2.0.1
connecting to: 10.0.0.3:27037/admin
> db.runCommand({"replSetInitiate" : {
... "_id" : "test",
... "members" : [
... {
... "_id" : 0,
... "host" : "10.0.0.3:27037"
... },
... {
... "_id" : 1,
... "host" : "10.0.0.4:27037"
... }
... ]}})
{
"info" : "Config now saved locally. Should come online in about a minute.",
"ok" : 1
}
>
执行以下shell命令后，如果看见红色字体标记的内容，则表示初始化成功
shell命令：
db.runCommand({"replSetInitiate" : {
"_id" : "test",
"members" : [
{
"_id" : 0,
"host" : "10.0.0.3:27037"
},
{
"_id" : 1,
"host" : "10.0.0.4:27037"
}
]}})
你也可以通过命令查看效果：
> rs.status()
{
"set" : "test",
"date" : ISODate("2011-12-06T07:44:29Z"),
"myState" : 1,
"members" : [
{
"_id" : 0,
"name" : "10.0.0.3:27037",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"optime" : {
"t" : 1323157008000,
"i" : 1
},
"optimeDate" : ISODate("2011-12-06T07:36:48Z"),
"self" : true
},
{
"_id" : 1,
"name" : "10.0.0.4:27037",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 455,
"optime" : {
"t" : 1323157008000,
"i" : 1
},
"optimeDate" : ISODate("2011-12-06T07:36:48Z"),
"lastHeartbeat" : ISODate("2011-12-06T07:44:28Z"),
"pingMs" : 2
}
],
"ok" : 1
}
加入仲裁节点
执行以下命令：
PRIMARY> rs.addArb("10.0.0.5:27037");
{ "ok" : 1 }
我们可以再次查看当前状态：
PRIMARY> rs.status()
{
"set" : "test",
"date" : ISODate("2011-12-06T07:46:21Z"),
"myState" : 1,
"members" : [
{
"_id" : 0,
"name" : "10.0.0.3:27037",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"optime" : {
"t" : 1323157549000,
"i" : 1
},
"optimeDate" : ISODate("2011-12-06T07:45:49Z"),
"self" : true
},
{
"_id" : 1,
"name" : "10.0.0.4:27037",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 567,
"optime" : {PRIMARY> db.isMaster();
{
"setName" : "test",
"ismaster" : true,
"secondary" : false,
"hosts" : [
"10.0.0.3:27037",
"10.0.0.4:27037"
],
"arbiters" : [
"10.0.0.5:27037"
],
"primary" : "10.0.0.3:27037",
"me" : "10.0.0.3:27037",
"maxBsonObjectSize" : 16777216,
"ok" : 1
}
"t" : 1323157549000,
"i" : 1
},
"optimeDate" : ISODate("2011-12-06T07:45:49Z"),
"lastHeartbeat" : ISODate("2011-12-06T07:46:20Z"),
"pingMs" : 0
},
{
"_id" : 2,
"name" : "10.0.0.5:27037",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER",
"uptime" : 22,
"optime" : {
"t" : 0,
"i" : 0
},
"optimeDate" : ISODate("1970-01-01T00:00:00Z"),
"lastHeartbeat" : ISODate("2011-12-06T07:46:19Z"),
"pingMs" : 0
}
],
"ok" : 1
}
rs.status()通过这个命令，可以查看各个节点的ip、角色已经是否正常
我们看到已经成功配置。
查看活跃节点：
PRIMARY> db.isMaster();
{
"setName" : "test",
"ismaster" : true,
"secondary" : false,
"hosts" : [
"10.0.0.3:27037",
"10.0.0.4:27037"
],
"arbiters" : [
"10.0.0.5:27037"
],
"primary" : "10.0.0.3:27037",
"me" : "10.0.0.3:27037",
"maxBsonObjectSize" : 16777216,
"ok" : 1
}
可以看到现在10.0.0.3：27037为活跃节点。
检测是否配置成功
可以强制primary和standard节点角色互换，从而验证是否能够实现副本集功能
rs.stepDown()
执行完成后：
SECONDARY> db.isMaster();
{
"setName" : "test",
"ismaster" : false,
"secondary" : true,
"hosts" : [
"10.0.0.3:27037",
"10.0.0.4:27037"
],
"arbiters" : [
"10.0.0.5:27037"
],
"primary" : "10.0.0.4:27037",
"me" : "10.0.0.3:27037",
"maxBsonObjectSize" : 16777216,
"ok" : 1
}
可以看到现在主节点已经修改为10.0.0.4：27037了。
我们也可以动态扩展增加节点（ip:10.0.0.5:27047）
hww@ubuntu:~$ mkdir -p ~/mongo1/db ~/mongo1/log hww@ubuntu:~$ mongod -dbpath ~/mongo1/db -logpath ~/mongo1/log/mongod.log -port 27037 -replSet test -maxConns=2000 -fork -logappend
进入活跃节点的服务器
hww@ubuntu4:~$ mongo 10.0.0.4:27037/admin
MongoDB shell version: 2.0.1
connecting to: 10.0.0.4:27037/admin
PRIMARY> rs.add("10.0.0.5:27047");
{ "ok" : 1 }
PRIMARY>
PRIMARY> rs.status()
{
"set" : "test",
"date" : ISODate("2011-12-06T07:59:36Z"),
"myState" : 1,
"syncingTo" : "10.0.0.3:27037",
"members" : [
{
"_id" : 0,
"name" : "10.0.0.3:27037",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1263,
"optime" : {
"t" : 1323158245000,
"i" : 1
},
"optimeDate" : ISODate("2011-12-06T07:57:25Z"),
"lastHeartbeat" : ISODate("2011-12-06T07:59:35Z"),
"pingMs" : 0
},
{
"_id" : 1,
"name" : "10.0.0.4:27037",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"optime" : {
"t" : 1323158245000,
"i" : 1
},
"optimeDate" : ISODate("2011-12-06T07:57:25Z"),
"self" : true
},
{
"_id" : 2,
"name" : "10.0.0.5:27037",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER",
"uptime" : 717,
"optime" : {
"t" : 0,
"i" : 0
},
"optimeDate" : ISODate("1970-01-01T00:00:00Z"),
"lastHeartbeat" : ISODate("2011-12-06T07:59:35Z"),
"pingMs" : 0
},
{
"_id" : 3,
"name" : "10.0.0.5:27047",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 125,
"optime" : {
"t" : 1323158245000,
"i" : 1
},
"optimeDate" : ISODate("2011-12-06T07:57:25Z"),
"lastHeartbeat" : ISODate("2011-12-06T07:59:35Z"),
"pingMs" : 0
}
],
"ok" : 1
}