MongoDB学习记录08-复制(副本集)

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什么是复制?

保障数据的安全性
数据高可用性 (24*7)
灾难恢复
无需停机维护（如备份，重建索引，压缩）
分布式读取数据
故障自动转移

副本集配置

新建如下文件夹

这里写图片描述

启动三个mongodb节点(一个仲裁节点，两个对等节点)

第一个成员

./mongod --replSet myapp --dbpath /usr/local/mongodb-linux-x86_64-3.4.4/nodes/01/ --logpath /usr/local/mongodb-linux-x86_64-3.4.4/nodes/01/1.log --port 40000 --fork

about to fork child process, waiting until server is ready for connections.forked process: 3099child process started successfully, parent exiting

第二个成员

./mongod --replSet myapp --dbpath /usr/local/mongodb-linux-x86_64-3.4.4/nodes/02/ --logpath /usr/local/mongodb-linux-x86_64-3.4.4/nodes/02/2.log --port 40001 --fork

about to fork child process, waiting until server is ready for connections.forked process: 3126child process started successfully, parent exiting

仲裁成员

./mongod --replSet myapp --dbpath /usr/local/mongodb-linux-x86_64-3.4.4/nodes/arbiter/ --logpath /usr/local/mongodb-linux-x86_64-3.4.4/nodes/arbiter/3.log --port 40002 --fork

about to fork child process, waiting until server is ready for connections.forked process: 3154child process started successfully, parent exiting

配置副本集节点

随便连接上其中一个非仲裁节点 , 这里连接上4000端口的，执行shell

执行命令

rs.initiate(    {        "_id":"myapp",         "members":[            {                "_id":0,                 "host":"192.168.7.127:40000"            }            ]    }    );

执行结果

{    "info2" : "no configuration specified. Using a default configuration for the set",    "me" : "localhost.localdomain:40000",    "ok" : 1}

在添加另外一个节点+

rs.add("192.168.7.127:40001");

{    "ok" : 1}

添加仲裁节点

rs.add("192.168.7.127:40002", {"arbiterOnly":true})

{    "ok" : 1}

查看节点信息

db.isMaster()

{    "hosts" : [        "localhost.localdomain:40000",        "192.168.7.127:40001"    ],    "arbiters" : [        "192.168.7.127:40002"    ],    "setName" : "myapp",    "setVersion" : 3,    "ismaster" : true,    "secondary" : false,    "primary" : "localhost.localdomain:40000",    "me" : "localhost.localdomain:40000",    "electionId" : ObjectId("7fffffff0000000000000001"),    "lastWrite" : {        "opTime" : {            "ts" : Timestamp(1494225341, 1),            "t" : NumberLong("1")        },        "lastWriteDate" : ISODate("2017-05-08T06:35:41.000Z")    },    "maxBsonObjectSize" : 16777216,    "maxMessageSizeBytes" : 48000000,    "maxWriteBatchSize" : 1000,    "localTime" : ISODate("2017-05-08T06:35:42.244Z"),    "maxWireVersion" : 5,    "minWireVersion" : 0,    "readOnly" : false,    "ok" : 1}

更加详细的信息查看

rs.status()

{    "set" : "myapp",    "date" : ISODate("2017-05-08T06:36:54.793Z"),    "myState" : 1,    "term" : NumberLong("1"),    "heartbeatIntervalMillis" : NumberLong("2000"),    "optimes" : {        "lastCommittedOpTime" : {            "ts" : Timestamp(1494225411, 1),            "t" : NumberLong("1")        },        "appliedOpTime" : {            "ts" : Timestamp(1494225411, 1),            "t" : NumberLong("1")        },        "durableOpTime" : {            "ts" : Timestamp(1494225411, 1),            "t" : NumberLong("1")        }    },    "members" : [        {            "_id" : 0,            "name" : "localhost.localdomain:40000",            "health" : 1,            "state" : 1,            "stateStr" : "PRIMARY",            "uptime" : 1382,            "optime" : {                "ts" : Timestamp(1494225411, 1),                "t" : NumberLong("1")            },            "optimeDate" : ISODate("2017-05-08T06:36:51.000Z"),            "electionTime" : Timestamp(1494224538, 2),            "electionDate" : ISODate("2017-05-08T06:22:18.000Z"),            "configVersion" : 3,            "self" : true        },        {            "_id" : 1,            "name" : "192.168.7.127:40001",            "health" : 1,            "state" : 2,            "stateStr" : "SECONDARY",            "uptime" : 522,            "optime" : {                "ts" : Timestamp(1494225411, 1),                "t" : NumberLong("1")            },            "optimeDurable" : {                "ts" : Timestamp(1494225411, 1),                "t" : NumberLong("1")            },            "optimeDate" : ISODate("2017-05-08T06:36:51.000Z"),            "optimeDurableDate" : ISODate("2017-05-08T06:36:51.000Z"),            "lastHeartbeat" : ISODate("2017-05-08T06:36:54.541Z"),            "lastHeartbeatRecv" : ISODate("2017-05-08T06:36:54.548Z"),            "pingMs" : NumberLong("0"),            "syncingTo" : "localhost.localdomain:40000",            "configVersion" : 3        },        {            "_id" : 2,            "name" : "192.168.7.127:40002",            "health" : 1,            "state" : 7,            "stateStr" : "ARBITER",            "uptime" : 128,            "lastHeartbeat" : ISODate("2017-05-08T06:36:54.541Z"),            "lastHeartbeatRecv" : ISODate("2017-05-08T06:36:51.512Z"),            "pingMs" : NumberLong("0"),            "configVersion" : 3        }    ],    "ok" : 1}

测试复制数据同步

添加一条测试数据到 40000
这里写图片描述

查看40001节点
这里写图片描述

到这里就说明成功配置了副本集

说明1：主节点可以读写数据，从节点只能读取数据，无法写数据.

{    "code" : 10107,    "codeName" : "NotMaster",    "errmsg" : "not master",    "message" : "not master",    "name" : "MongoError",    "ok" : 0}

说明2 : 主节点挂掉，从节点自动升级为主节点，这时候可以进行读写，重启旧的主节点，那么旧的主节点改成从节点

副本集在驱动中的应用

当一个连接指向一个副本集的时候，会发送 isMaster 来自动辨别是否为主节点.
如果主节点挂了，会重新获取主节点，从而进行自动转移故障.

        List servers = new ArrayList();        servers.add(new ServerAddress("192.168.7.127", 40000));        servers.add(new ServerAddress("192.168.7.127", 40001));        MongoClient client = new MongoClient(servers);

移除节点

rs.remove("ip:port")

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