MongoDB副本集

关于副本集的理论我就不介绍了。下面说下如何实现副本集的操作。

前提

  1. 首先就是要安装mongoDB服务器了。我建议按照我之前写的这篇文章进行安装。
  2. 准备三台以上的服务器。然后同时安装MongoDB。我们三台服务器的IP分别是(10.55.160.91,10.55.160.92,10.55.160.93)

部署一个副本集

  1. 修改配置文件。
    首先我们打开配置文件。

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    vim /etc/mongod.conf

    找到bindIp: 127.0.0.1这行,我们需要对这行进行注释。变成如下这样:

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    #bindIp: 127.0.0.1  # Listen to local interface only, comment to listen on all interfaces.

    因为这个bindIp代表只允许本机进行连接,然后不允许其他服务器进行连接,那么,下面就没有办法继续执行了。

    找到#replication:这行我们将其注释去掉,然后下面增加一行,变成下面这样:

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    replication:
    replSetName: test

    replSetName表示副本集组的名字(test是我自己写的,你们也可以写你们自己的喜欢的名字),比如,我们要将三台服务器进行关联,那么我们就要将三台服务器都设置为相同的名字。

    然后如果三台服务器的MongoDB都已经启动了,那么就执行以下命令:

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    service mongod restart

    如果没有启动就执行以下命令:

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    service mongod start
  2. 链接到任意一台服务器。
    我选择的是链接到10.55.160.91。也就是我现在正在操作的这一台服务器。然后登录:

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    mongo
  3. 初始化副本集。
    初始化副本集,我们需要使用rs.initiate()方法。
    我现在需要添加的是三台服务器,我们可以执行以下方法:

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    rs.initiate({
    _id: "test",
    version: 1,
    members: [
    { _id: 0, host : "10.55.160.91:27017" },
    { _id: 1, host : "10.55.160.92:27017" },
    { _id: 2, host : "10.55.160.93:27017" }
    ]
    })

    当返回值显示为如下的时候,就代表成功了:

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    { "ok" : 1 }
  4. 这样就完成了,是不是很简单。哈哈。

然后你就发现你的输入命令的标题就变了。变成如下这样了:

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test:OTHER>

不管它,我们继续执行操作,执行rs.status(),查看当前状态。

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rs.status()

查看返回值:

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{
"set" : "test",
"date" : ISODate("2016-09-22T08:08:36.607Z"),
"myState" : 1,
"term" : NumberLong(1),
"heartbeatIntervalMillis" : NumberLong(2000),
"members" : [
{
"_id" : 0,
"name" : "10.55.160.91:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 154,
"optime" : {
"ts" : Timestamp(1474531710, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2016-09-22T08:08:30Z"),
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1474531709, 1),
"electionDate" : ISODate("2016-09-22T08:08:29Z"),
"configVersion" : 1,
"self" : true
},
{
"_id" : 1,
"name" : "10.55.160.92:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 17,
"optime" : {
"ts" : Timestamp(1474531710, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2016-09-22T08:08:30Z"),
"lastHeartbeat" : ISODate("2016-09-22T08:08:35.966Z"),
"lastHeartbeatRecv" : ISODate("2016-09-22T08:08:32.078Z"),
"pingMs" : NumberLong(0),
"syncingTo" : "10.55.160.91:27017",
"configVersion" : 1
},
{
"_id" : 2,
"name" : "10.55.160.93:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 17,
"optime" : {
"ts" : Timestamp(1474531710, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2016-09-22T08:08:30Z"),
"lastHeartbeat" : ISODate("2016-09-22T08:08:35.966Z"),
"lastHeartbeatRecv" : ISODate("2016-09-22T08:08:32.078Z"),
"pingMs" : NumberLong(0),
"syncingTo" : "10.55.160.91:27017",
"configVersion" : 1
}
],
"ok" : 1
}

我们主要是看members字段里面的stateStr的值。

很幸运,我当前执行命令的服务器被推举为主服务器。

如果你们现在服务器显示当前的服务器的状态是:SECONDARY。表示该服务器是从服务器,我们需要查看哪台服务器为主服务器,也就是"stateStr" : "PRIMARY"。我们需要在主服务器才进行进行操作,当然,也有强行在从服务器进行操作的办法。这里先不说。

这样我们就可以在主服务器进行操作了。比如存储数据。

添加成员

比如现在又有了一台服务器(10.55.160.94)需要加入到这个副本集中。我们可以使用rs.add()进行添加服务器。

首先我们还是别忘了修改配置文件的步骤。。。。。。修改完成配置文件之后重启Mongod,然后在主服务器执行如下命令:

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rs.add("10.55.160.94:27017")

在执行该命令之后,可能会出现主服务器的选择,我们要注意主服务器是否已经变成了别的服务器。我们可以使用rs.status()查看新的主服务器是什么。

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{
"set" : "test",
"date" : ISODate("2016-09-22T09:28:53.913Z"),
"myState" : 1,
"term" : NumberLong(6),
"heartbeatIntervalMillis" : NumberLong(2000),
"members" : [
{
"_id" : 0,
"name" : "10.55.160.91:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1202,
"optime" : {
"ts" : Timestamp(1474536460, 1),
"t" : NumberLong(6)
},
"optimeDate" : ISODate("2016-09-22T09:27:40Z"),
"lastHeartbeat" : ISODate("2016-09-22T09:28:52.089Z"),
"lastHeartbeatRecv" : ISODate("2016-09-22T09:28:52.095Z"),
"pingMs" : NumberLong(0),
"syncingTo" : "10.55.160.93:27017",
"configVersion" : 6
},
{
"_id" : 1,
"name" : "10.55.160.92:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1202,
"optime" : {
"ts" : Timestamp(1474536460, 1),
"t" : NumberLong(6)
},
"optimeDate" : ISODate("2016-09-22T09:27:40Z"),
"lastHeartbeat" : ISODate("2016-09-22T09:28:52.089Z"),
"lastHeartbeatRecv" : ISODate("2016-09-22T09:28:52.095Z"),
"pingMs" : NumberLong(0),
"syncingTo" : "10.55.160.93:27017",
"configVersion" : 6
},
{
"_id" : 2,
"name" : "10.55.160.93:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 1207,
"optime" : {
"ts" : Timestamp(1474536460, 1),
"t" : NumberLong(6)
},
"optimeDate" : ISODate("2016-09-22T09:27:40Z"),
"electionTime" : Timestamp(1474536383, 1),
"electionDate" : ISODate("2016-09-22T09:26:23Z"),
"configVersion" : 6,
"self" : true
},
{
"_id" : 3,
"name" : "10.55.160.94:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 71,
"optime" : {
"ts" : Timestamp(1474536460, 1),
"t" : NumberLong(6)
},
"optimeDate" : ISODate("2016-09-22T09:27:40Z"),
"lastHeartbeat" : ISODate("2016-09-22T09:28:52.089Z"),
"lastHeartbeatRecv" : ISODate("2016-09-22T09:28:52.059Z"),
"pingMs" : NumberLong(0),
"configVersion" : 6
}
],
"ok" : 1
}

修改服务器的优先级

比如我们新添加的服务器(10.55.160.94),这个服务器的配置较高。我希望优先让它成为主服务器。我们可以通过如下方式进行修改:

首先我们可以通过rs.conf来查看是第几个游标。

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rs.conf()

返回值如下:

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{
"_id" : "test",
"version" : 6,
"protocolVersion" : NumberLong(1),
"members" : [
{
"_id" : 0,
"host" : "10.55.160.91:27017",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {

},
"slaveDelay" : NumberLong(0),
"votes" : 1
},
{
"_id" : 1,
"host" : "10.55.160.92:27017",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {

},
"slaveDelay" : NumberLong(0),
"votes" : 1
},
{
"_id" : 2,
"host" : "10.55.160.93:27017",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {

},
"slaveDelay" : NumberLong(0),
"votes" : 1
},
{
"_id" : 3,
"host" : "10.55.160.94:27017",
"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("57e391736b7581c82cc75a83")
}
}

我们可以看到它的游标是第3个(从0开始计算)。
我们可以这样进行修改:

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cfg = rs.conf()
cfg.members[3].priority = 10
rs.reconfig(cfg)

过了一会,我们就看到主服务器变成(10.55.160.94)了。

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{
"set" : "test",
"date" : ISODate("2016-09-22T10:18:48.348Z"),
"myState" : 2,
"term" : NumberLong(7),
"syncingTo" : "10.55.160.94:27017",
"heartbeatIntervalMillis" : NumberLong(2000),
"members" : [
{
"_id" : 0,
"name" : "10.55.160.91:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 4197,
"optime" : {
"ts" : Timestamp(1474539241, 2),
"t" : NumberLong(7)
},
"optimeDate" : ISODate("2016-09-22T10:14:01Z"),
"lastHeartbeat" : ISODate("2016-09-22T10:18:46.676Z"),
"lastHeartbeatRecv" : ISODate("2016-09-22T10:18:46.535Z"),
"pingMs" : NumberLong(0),
"syncingTo" : "10.55.160.94:27017",
"configVersion" : 7
},
{
"_id" : 1,
"name" : "10.55.160.92:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 4197,
"optime" : {
"ts" : Timestamp(1474539241, 2),
"t" : NumberLong(7)
},
"optimeDate" : ISODate("2016-09-22T10:14:01Z"),
"lastHeartbeat" : ISODate("2016-09-22T10:18:46.676Z"),
"lastHeartbeatRecv" : ISODate("2016-09-22T10:18:46.674Z"),
"pingMs" : NumberLong(0),
"syncingTo" : "10.55.160.94:27017",
"configVersion" : 7
},
{
"_id" : 2,
"name" : "10.55.160.93:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 4202,
"optime" : {
"ts" : Timestamp(1474539241, 2),
"t" : NumberLong(7)
},
"optimeDate" : ISODate("2016-09-22T10:14:01Z"),
"syncingTo" : "10.55.160.94:27017",
"configVersion" : 7,
"self" : true
},
{
"_id" : 3,
"name" : "10.55.160.94:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 3066,
"optime" : {
"ts" : Timestamp(1474539241, 2),
"t" : NumberLong(7)
},
"optimeDate" : ISODate("2016-09-22T10:14:01Z"),
"lastHeartbeat" : ISODate("2016-09-22T10:18:46.676Z"),
"lastHeartbeatRecv" : ISODate("2016-09-22T10:18:47.546Z"),
"pingMs" : NumberLong(0),
"electionTime" : Timestamp(1474539241, 1),
"electionDate" : ISODate("2016-09-22T10:14:01Z"),
"configVersion" : 7
}
],
"ok" : 1
}

添加仲裁者服务器

仲裁者服务器只参与投票,而不是进行数据的存储。别忘了定义副本集名称。

我们可以使用rs.addArb()来进行添加一台新的服务器(10.55.160.95)为仲裁服务器。

命令如下:

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rs.addArb('10.55.160.95')

返回{ "ok" : 1 }就正常执行了。这时我们通过rs.status()来看一下服务器的状态。

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{
"set" : "test",
"date" : ISODate("2016-09-23T02:54:44.854Z"),
"myState" : 2,
"term" : NumberLong(9),
"syncingTo" : "10.55.160.94:27017",
"heartbeatIntervalMillis" : NumberLong(2000),
"members" : [
{
"_id" : 0,
"name" : "10.55.160.91:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 141,
"optime" : {
"ts" : Timestamp(1474599221, 1),
"t" : NumberLong(9)
},
"optimeDate" : ISODate("2016-09-23T02:53:41Z"),
"syncingTo" : "10.55.160.94:27017",
"configVersion" : 8,
"self" : true
},
{
"_id" : 1,
"name" : "10.55.160.92:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 95,
"optime" : {
"ts" : Timestamp(1474599221, 1),
"t" : NumberLong(9)
},
"optimeDate" : ISODate("2016-09-23T02:53:41Z"),
"lastHeartbeat" : ISODate("2016-09-23T02:54:43.113Z"),
"lastHeartbeatRecv" : ISODate("2016-09-23T02:54:44.091Z"),
"pingMs" : NumberLong(0),
"syncingTo" : "10.55.160.94:27017",
"configVersion" : 8
},
{
"_id" : 2,
"name" : "10.55.160.93:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 86,
"optime" : {
"ts" : Timestamp(1474599221, 1),
"t" : NumberLong(9)
},
"optimeDate" : ISODate("2016-09-23T02:53:41Z"),
"lastHeartbeat" : ISODate("2016-09-23T02:54:43.113Z"),
"lastHeartbeatRecv" : ISODate("2016-09-23T02:54:43.121Z"),
"pingMs" : NumberLong(0),
"syncingTo" : "10.55.160.94:27017",
"configVersion" : 8
},
{
"_id" : 3,
"name" : "10.55.160.94:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 83,
"optime" : {
"ts" : Timestamp(1474599221, 1),
"t" : NumberLong(9)
},
"optimeDate" : ISODate("2016-09-23T02:53:41Z"),
"lastHeartbeat" : ISODate("2016-09-23T02:54:43.113Z"),
"lastHeartbeatRecv" : ISODate("2016-09-23T02:54:43.134Z"),
"pingMs" : NumberLong(0),
"electionTime" : Timestamp(1474599220, 1),
"electionDate" : ISODate("2016-09-23T02:53:40Z"),
"configVersion" : 8
},
{
"_id" : 4,
"name" : "10.55.160.95:27017",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER",
"uptime" : 79,
"lastHeartbeat" : ISODate("2016-09-23T02:54:43.113Z"),
"lastHeartbeatRecv" : ISODate("2016-09-23T02:54:42.775Z"),
"pingMs" : NumberLong(0),
"configVersion" : 8
}
],
"ok" : 1
}

我们可以看到IP为10.55.160.95这台服务器,它的stateStr的值是ARBITER。这个就代表是仲裁者的角色。

移除成员

移除成员我们使用rs.remove()方法就可以了。

比如我们要移除10.55.160.93。我们可以使用如下命令:

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rs.remove('10.55.160.93:27017')

我们可以使用rs.status()查看一下返回值:

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{
"set" : "test",
"date" : ISODate("2016-09-23T03:15:21Z"),
"myState" : 2,
"term" : NumberLong(9),
"syncingTo" : "10.55.160.94:27017",
"heartbeatIntervalMillis" : NumberLong(2000),
"members" : [
{
"_id" : 0,
"name" : "10.55.160.91:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1377,
"optime" : {
"ts" : Timestamp(1474600512, 1),
"t" : NumberLong(9)
},
"optimeDate" : ISODate("2016-09-23T03:15:12Z"),
"syncingTo" : "10.55.160.94:27017",
"configVersion" : 9,
"self" : true
},
{
"_id" : 1,
"name" : "10.55.160.92:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 1331,
"optime" : {
"ts" : Timestamp(1474600512, 1),
"t" : NumberLong(9)
},
"optimeDate" : ISODate("2016-09-23T03:15:12Z"),
"lastHeartbeat" : ISODate("2016-09-23T03:15:20.593Z"),
"lastHeartbeatRecv" : ISODate("2016-09-23T03:15:20.592Z"),
"pingMs" : NumberLong(0),
"syncingTo" : "10.55.160.94:27017",
"configVersion" : 9
},
{
"_id" : 3,
"name" : "10.55.160.94:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 1319,
"optime" : {
"ts" : Timestamp(1474600512, 1),
"t" : NumberLong(9)
},
"optimeDate" : ISODate("2016-09-23T03:15:12Z"),
"lastHeartbeat" : ISODate("2016-09-23T03:15:20.595Z"),
"lastHeartbeatRecv" : ISODate("2016-09-23T03:15:20.582Z"),
"pingMs" : NumberLong(0),
"electionTime" : Timestamp(1474599220, 1),
"electionDate" : ISODate("2016-09-23T02:53:40Z"),
"configVersion" : 9
},
{
"_id" : 4,
"name" : "10.55.160.95:27017",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER",
"uptime" : 1315,
"lastHeartbeat" : ISODate("2016-09-23T03:15:20.596Z"),
"lastHeartbeatRecv" : ISODate("2016-09-23T03:15:17.585Z"),
"pingMs" : NumberLong(0),
"configVersion" : 9
}
],
"ok" : 1
}

发现10.55.160.93这个服务器已经从副本集中消失了。

更换副本集成员

我们可以使用如下办法进行快速更换成员:

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cfg = rs.conf()
cfg.members[0].host = "10.55.160.93"
rs.reconfig(cfg)

我们看之前被替换走的成员,它的状态已经变成这样了:

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{
"state" : 10,
"stateStr" : "REMOVED",
"uptime" : 3162,
"optime" : {
"ts" : Timestamp(1474602195, 1),
"t" : NumberLong(9)
},
"optimeDate" : ISODate("2016-09-23T03:43:15Z"),
"ok" : 0,
"errmsg" : "Our replica set config is invalid or we are not a member of it",
"code" : 93
}