mongodb的复制集

baodeyun 发表于 2018-10-20 11:32:41

下载地址：https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-rhel62-3.6.8.tgz

Primary:192.168.20.141

Secondaries:192.168.20.142

Arbiter:192.168.20.143

mongodb安装：(所有节点都安装)

tar xf mongodb-linux-x86_64-rhel62-3.6.8.tgz

mv mongodb-linux-x86_64-rhel62-3.6.8 /usr/local/mongodb

mkdir /usr/local/mongodb/{data,log} -p

# cat /usr/local/mongodb/mongodb.conf

pidfilepath=/usr/local/mongodb/log/mongod.pid

logpath=/usr/local/mongodb/log/mongod.log

dbpath=/usr/local/mongodb/data

logappend=true

bind_ip=192.168.20.141

port=27017

fork=true

replSet=rs0

# cat /etc/profile

......

export PATH=$PATH:/usr/local/mongodb/bin

# mongod --config /usr/local/mongodb/mongodb.conf

常见错误：

# mongod --config /usr/local/mongodb/mongodb.conf
about to fork child process, waiting until server is ready for connections.
forked process: 1529
ERROR: child process failed, exited with error number 48
To see additional information in this output, start without the "--fork" option.

由于我的测试环境下没有数据，我将data数据目录下的文件全部清空，然后--repair

rm -rf data/mongod.lock

mongod --repair

重启：

mongod --config /usr/local/mongodb/mongodb.conf

登陆mongodb主节点：

初始化复制集：（集合："sr0" 第一个成员为："192.168.20.141:27017"）

# mongo 192.168.20.141:27017

> rs.initiate({_id: "rs0",members: [{ _id: 0 , host: "192.168.20.141:27017" }]})

rs0:OTHER>                //接着回车，显示这个节点为Primary主节点
rs0:PRIMARY>

接着添加另一个成员：

rs0:PRIMARY> rs.add("192.168.20.142:27017")

查看成员信息：（或者使用：db.isMaster()）

rs0:PRIMARY> rs.status()
{
"set" : "rs0",
"date" : ISODate("2018-10-15T15:59:47.565Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1539619178, 1),
"t" : NumberLong(1)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1539619178, 1),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1539619178, 1),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1539619178, 1),
"t" : NumberLong(1)
}
},
"members" : [
{
"_id" : 0,
"name" : "192.168.20.141:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 107,
"optime" : {
"ts" : Timestamp(1539619178, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2018-10-15T15:59:38Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1539619130, 2),
"electionDate" : ISODate("2018-10-15T15:58:50Z"),
"configVersion" : 2,
"self" : true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 1,
"name" : "192.168.20.142:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 9,
"optime" : {
"ts" : Timestamp(1539619178, 1),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1539619178, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2018-10-15T15:59:38Z"),
"optimeDurableDate" : ISODate("2018-10-15T15:59:38Z"),
"lastHeartbeat" : ISODate("2018-10-15T15:59:46.107Z"),
"lastHeartbeatRecv" : ISODate("2018-10-15T15:59:47.116Z"),
"pingMs" : NumberLong(1),
"lastHeartbeatMessage" : "",
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "",
"configVersion" : 2
}
],
"ok" : 1,
"operationTime" : Timestamp(1539619178, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1539619178, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}

这中方法也可以查询：

rs0:PRIMARY> use admin
switched to db admin
rs0:PRIMARY> db.runCommand( {replSetGetStatus : 1} )
{
"set" : "rs0",
"date" : ISODate("2018-10-15T17:31:13.924Z"),
"myState" : 1,
"term" : NumberLong(2),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1539624666, 1),
"t" : NumberLong(2)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1539624666, 1),
"t" : NumberLong(2)
},
"appliedOpTime" : {
"ts" : Timestamp(1539624666, 1),
"t" : NumberLong(2)
},
"durableOpTime" : {
"ts" : Timestamp(1539624666, 1),
"t" : NumberLong(2)
}
},
"members" : [
{
"_id" : 0,
"name" : "192.168.20.141:27017",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 4387,
"optime" : {
"ts" : Timestamp(1539624666, 1),
"t" : NumberLong(2)
},
"optimeDurable" : {
"ts" : Timestamp(1539624666, 1),
"t" : NumberLong(2)
},
"optimeDate" : ISODate("2018-10-15T17:31:06Z"),
"optimeDurableDate" : ISODate("2018-10-15T17:31:06Z"),
"lastHeartbeat" : ISODate("2018-10-15T17:31:12.667Z"),
"lastHeartbeatRecv" : ISODate("2018-10-15T17:31:12.668Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "192.168.20.142:27017",
"syncSourceHost" : "192.168.20.142:27017",
"syncSourceId" : 1,
"infoMessage" : "",
"configVersion" : 3
},
{
"_id" : 1,
"name" : "192.168.20.142:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 5600,
"optime" : {
"ts" : Timestamp(1539624666, 1),
"t" : NumberLong(2)
},
"optimeDate" : ISODate("2018-10-15T17:31:06Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "",
"electionTime" : Timestamp(1539620134, 1),
"electionDate" : ISODate("2018-10-15T16:15:34Z"),
"configVersion" : 3,
"self" : true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 2,
"name" : "192.168.20.143:27017",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER",
"uptime" : 4636,
"lastHeartbeat" : ISODate("2018-10-15T17:31:12.677Z"),
"lastHeartbeatRecv" : ISODate("2018-10-15T17:31:13.313Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "",
"configVersion" : 3
}
],
"ok" : 1,
"operationTime" : Timestamp(1539624666, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1539624666, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}

详细说明如下：
"_id" :#集群中节点编号

"name" :#成员服务器名称及端口
"health" :#表示成员中的健康状态（0:down;1:up）

"state" :#为0~10，表示成员的当前状态
"stateStr" :#描述该成员是主库（PRIMARY）还是备库（SECONDARY）

"uptime" :#该成员在线时间（秒）
"optime" :#成员最后一次应用日志(oplog)的信息

"optimeDate" :#成员最后一次应用日志(oplog)的时间
"electionTime" :#当前primary从操作日志中选举信息

"electionDate" :#当前primary被选定为primary的日期
"configVersion" :#mongodb版本

"self" :#为true 表示当前节点
切换到备库中，能连接但是不能操作：

rs0:SECONDARY> show dbs
2018-10-16T01:32:31.781+0800 E QUERY Error: listDatabases failed:{
"operationTime" : Timestamp(1539624746, 1),
"ok" : 0,
"errmsg" : "not master and slaveOk=false",
"code" : 13435,
"codeName" : "NotMasterNoSlaveOk",
"$clusterTime" : {
"clusterTime" : Timestamp(1539624746, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
} :
_getErrorWithCode@src/mongo/shell/utils.js:25:13
Mongo.prototype.getDBs@src/mongo/shell/mongo.js:65:1
shellHelper.show@src/mongo/shell/utils.js:849:19
shellHelper@src/mongo/shell/utils.js:739:15
@(shellhelp2):1:1

从库开启都操作（）

rs0:SECONDARY> rs.slaveOk();
rs0:SECONDARY> show dbs
admin 0.000GB
config0.000GB
local 0.000GB

模拟主库不能使用，把主库停止，经测试从库可以自动升级成主库。

再次启动主库时，主库就变成从库了。

仲裁节点的安装：

# cat /usr/local/mongodb/mongodb.conf

pidfilepath=/usr/local/mongodb/log/mongod.pid

logpath=/usr/local/mongodb/log/mongod.log

dbpath=/usr/local/mongodb/arbiter

logappend=false

bind_ip=192.168.20.143

port=27017

fork=true

replSet=rs0

启动mongodb的仲裁节点：

# mongod --config /usr/local/mongodb/mongodb.conf

在主节点添加仲裁节点并查看结果：

rs0:SECONDARY> rs.addArb("192.168.20.143：27017")

查看结果：

rs0:PRIMARY> db.isMaster()
{
"hosts" : [
"192.168.20.141:27017",
"192.168.20.142:27017"
],
"arbiters" : [
"192.168.20.143:27017"
],
"setName" : "rs0",
"setVersion" : 3,
"ismaster" : true,
"secondary" : false,
"primary" : "192.168.20.142:27017",
"me" : "192.168.20.142:27017",
"electionId" : ObjectId("7fffffff0000000000000002"),
"lastWrite" : {
"opTime" : {
"ts" : Timestamp(1539625486, 1),
"t" : NumberLong(2)
},
"lastWriteDate" : ISODate("2018-10-15T17:44:46Z"),
"majorityOpTime" : {
"ts" : Timestamp(1539625486, 1),
"t" : NumberLong(2)
},
"majorityWriteDate" : ISODate("2018-10-15T17:44:46Z")
},
"maxBsonObjectSize" : 16777216,
"maxMessageSizeBytes" : 48000000,
"maxWriteBatchSize" : 100000,
"localTime" : ISODate("2018-10-15T17:44:50.159Z"),
"logicalSessionTimeoutMinutes" : 30,
"minWireVersion" : 0,
"maxWireVersion" : 6,
"readOnly" : false,
"ok" : 1,
"operationTime" : Timestamp(1539625486, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1539625486, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
至此安装完毕。

登陆到仲裁节点：

# mongo 192.168.20.143:27017
MongoDB shell version v3.6.8
connecting to: mongodb://192.168.20.143:27017/test
MongoDB server version: 3.6.8
Server has startup warnings:
2018-10-16T00:13:05.892+0800 I STORAGE
2018-10-16T00:13:05.892+0800 I STORAGE ** WARNING: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine
2018-10-16T00:13:05.892+0800 I STORAGE **       See http://dochub.mongodb.org/core/prodnotes-filesystem
2018-10-16T00:13:06.958+0800 I CONTROL
2018-10-16T00:13:06.958+0800 I CONTROL ** WARNING: Access control is not enabled for the database.
2018-10-16T00:13:06.958+0800 I CONTROL **       Read and write access to data and configuration is unrestricted.
2018-10-16T00:13:06.958+0800 I CONTROL ** WARNING: You are running this process as the root user, which is not recommended.
2018-10-16T00:13:06.958+0800 I CONTROL
2018-10-16T00:13:06.959+0800 I CONTROL
2018-10-16T00:13:06.959+0800 I CONTROL ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2018-10-16T00:13:06.959+0800 I CONTROL **    We suggest setting it to 'never'
2018-10-16T00:13:06.959+0800 I CONTROL
2018-10-16T00:13:06.959+0800 I CONTROL ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2018-10-16T00:13:06.959+0800 I CONTROL **    We suggest setting it to 'never'
2018-10-16T00:13:06.959+0800 I CONTROL

rs0:ARBITER> rs.slaveOk();

rs0:ARBITER> db.isMaster()
{
"hosts" : [
"192.168.20.141:27017",
"192.168.20.142:27017"
],
"arbiters" : [
"192.168.20.143:27017"
],
"setName" : "rs0",
"setVersion" : 3,
"ismaster" : false,
"secondary" : false,
"primary" : "192.168.20.142:27017",
"arbiterOnly" : true,
"me" : "192.168.20.143:27017",
"lastWrite" : {
"opTime" : {
"ts" : Timestamp(1539625616, 1),
"t" : NumberLong(2)
},
"lastWriteDate" : ISODate("2018-10-15T17:46:56Z"),
"majorityOpTime" : {
"ts" : Timestamp(1539625616, 1),
"t" : NumberLong(2)
},
"majorityWriteDate" : ISODate("2018-10-15T17:46:56Z")
},
"maxBsonObjectSize" : 16777216,
"maxMessageSizeBytes" : 48000000,
"maxWriteBatchSize" : 100000,
"localTime" : ISODate("2018-10-15T17:47:02.962Z"),
"minWireVersion" : 0,
"maxWireVersion" : 6,
"readOnly" : false,
"ok" : 1
}

rs0:ARBITER> show dbs
local0.000GB

arbiter作为仲裁者，没有数据副本存储在本地，能读取复制集的信息

上面介绍的是三台mongodb节点：一主一备一仲裁，这样，主节点挂了后，通过仲裁机制将primary自动切换到备机上！
如果上面的三台mongodb节点：一主两备，没有仲裁节点，那么主节点挂了后，primary会自动切换到其余两台备节点中的一台上！

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40一主两从的mongodb配置和上面一主一从的配置一样。
多加的一个从节点，在主节点登陆mongodb，使用rs.add命令将这个成员加到集群中即可！
一主两从的模式，比如：主节点192.168.20.141的mongodb服务程序挂了后，另外两个从节点中的一个（比如192.168.20.142）会自动变成primary主节点，
另一个节点192.168.20.143则是新的主节点（192.168.20.142）的从节点。
++++++++++++++++++++++++++++++如果想让切换回原来的主节点，做法如下+++++++++++++++++++++++++++++++1）恢复原来的主节点192.168.20.141的mongodb服务，使用命令rs.status() 确认数据集成员运行正常。
2）到次节点192.168.20.143中登录mongodb，运行freeze使其120内不会变为主节点。 > rs.freeze(120)
3) 到新的主节点192.168.20.142中强制切换主节点，stepDown将阻止长事务和写入操作 > rs.stepDown(120)
4）此时sign-mongo01.wangshibo.cn节点变成primary主节点。使用rs.status()命令可以查看到集群状态。
+++++++++++++++++++++++若要使某个节点永远不会变为主节点，设置优先级为0即可+++++++++++++++++++++++登陆当前主节点的mongodb，执行下面操作：
rs0:PRIMARY> cfg = rs.conf() rs0:PRIMARY> cfg.members.priority = 0.5
rs0:PRIMARY> cfg.members.priority = 0.5 rs0:PRIMARY> cfg.members.priority = 0
rs0:PRIMARY> rs.reconfig(cfg)
说明：其中成员编号0/1/2为 rs.status()中的 "_id"值
members表示192.168.20.143，则它将永远不会变成主节点！因为优先级设置为0了！
++++++++++++++++++++++++++++++++移除一个复制成员（两种方法）++++++++++++++++++++++++++++++++++++登陆当前主节点的mongodb，执行下面操作：
rs0:PRIMARY> rs.remove("192.168.20.143:27017") rs0:PRIMARY> rs.conf()
或者：
rs0:PRIMARY> cfg = rs.conf() rs0:PRIMARY> cfg.members.splice(2,1)
rs0:PRIMARY> rs.reconfig(cfg)
移除后到移除的节点服务器（即192.168.20.143），更改配置文件mongod.conf#replSet=rs0    //将这一行注释
然后再重启mongodb服务，这就完成了移除（数据库文件仍保留在当前服务器）。

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运维网's Archiver

mongodb的复制集