MongoDB復制集技術

為什么使用MongogDB復制集技術?

mysql中:一主一從，一主多從結構存在的問題
1、    fileover（故障轉移）
        a)    選主投票
        b)    切換
2、    是否對就用透明化
3、    數據補償的問題
        a)    兩階段數據補償
4、    解決方法 mysql中使用MHA+VIP + binlogserver

  mongodb通過復制集技術解決以上所有問題，不需要第三方軟件，自已原生支持

  MongoDB復制集簡介

一組Mongodb復制集，就是一組mongod進程，這些進程維護同一個數據集合。復制集提供了數據冗余和高等級的可靠性，這是生產部署的基礎。
保證數據在生產部署時的冗余和可靠性，通過在不同的機器上保存副本來保證數據的不會因為單點損壞而丟失。能夠隨時應對數據丟失、機器損壞帶來的風險，牛逼到不行。換一句話來說，還能提高讀取能力，用戶的讀取服務器和寫入服務器在不同的地方，而且，由不同的服務器為不同的用戶提供服務，提高整個系統的負載，簡直就是雲存儲的翻版...一組復制集就是一組mongod實例掌管同一個數據集，實例可以在不同的機器上面。實例中包含一個主導，接受客戶端所有的寫入操作，其他都是副本實例，從主服務器上獲得數據並保持同步。
主服務器很重要，包含了所有的改變操作（寫）的日志。但是副本服務器集群包含有所有的主服務器數據，因此當主服務器掛掉了，就會在副本服務器上重新選取一個成為主服務器。每個復制集還有一個仲裁者，仲裁者不存儲數據，只是負責通過心跳包來確
認集群中集合的數量，並在主服務器選舉的時候作為仲裁決定結果。

 

 復制的基本架構

一個包含3個mongod的復制集架構如下所示

如果主服務器失效，會變成：

如果加上可選的仲裁者：

 

如果主服務器失效：

復制集技術實現

搭建三節點MongoDB復制集

#創建多mongodb多實例
mkdir -p /mongodb/28017/conf /mongodb/28017/data /mongodb/28017/log
mkdir -p /mongodb/28018/conf /mongodb/28018/data /mongodb/28018/log
mkdir -p /mongodb/28019/conf /mongodb/28019/data /mongodb/28019/log
mkdir -p /mongodb/28020/conf /mongodb/28020/data /mongodb/28020/log
#創建mongodb多
vim  /mongodb/28017/conf/mongod.conf
systemLog:
  destination: file
  path: /mongodb/28017/log/mongodb.log
  logAppend: true
storage:
  journal:
    enabled: true
  dbPath: /mongodb/28017/data
  directoryPerDB: true
  #engine: wiredTiger
  wiredTiger:
    engineConfig:
      cacheSizeGB: 1
      directoryForIndexes: true
    collectionConfig:
      blockCompressor: zlib
    indexConfig:
      prefixCompression: true
processManagement:
  fork: true
net:
  port: 28017
replication:
  oplogSizeMB: 2048
  replSetName: my_repl




\cp  /mongodb/28017/conf/mongod.conf  /mongodb/28018/conf/
\cp  /mongodb/28017/conf/mongod.conf  /mongodb/28019/conf/
\cp  /mongodb/28017/conf/mongod.conf  /mongodb/28020/conf/
sed 's#28017#28018#g' /mongodb/28018/conf/mongod.conf -i
sed 's#28017#28019#g' /mongodb/28019/conf/mongod.conf -i
sed 's#28017#28020#g' /mongodb/28020/conf/mongod.conf -i


chown -R mongod:mongod /mongodb/

su - mongod
mongod -f /mongodb/28017/conf/mongod.conf
mongod -f /mongodb/28018/conf/mongod.conf
mongod -f /mongodb/28019/conf/mongod.conf
mongod -f /mongodb/28020/conf/mongod.conf

 

登錄

 

mongo --port=28017
use admin
config = {_id: 'my_repl', members: [
                          {_id: 0, host: '10.0.0.134:28017'},
                          {_id: 1, host: '10.0.0.134:28018'},
                          {_id: 2, host: '10.0.0.134:28019'}]
          }
rs.initiate(config)
use test;
db.movies.insert([ { "title" : "Jaws", "year" : 1975, "imdb_rating" : 8.1 },{ "title" : "Batman", "year" : 1989, "imdb_rating" : 7.6 },
] );

 

 

#復制集狀態查詢 在哪個節點都可以看

[mongod@mongo ~]$ mongo --port=28017
MongoDB shell version: 3.2.8
connecting to: 127.0.0.1:28017/test
my_repl:PRIMARY> rs.status();
{
    "set" : "my_repl",
    "date" : ISODate("2018-01-04T09:06:52.951Z"),
    "myState" : 1,
    "term" : NumberLong(1),
    "heartbeatIntervalMillis" : NumberLong(2000),
    "members" : [
        {
            "_id" : 0,
            "name" : "10.0.0.134:28017", #ip port "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY", "PRIMARY" 主節點 "uptime" : 772,
            "optime" : {
                "ts" : Timestamp(1515056188, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T08:56:28Z"),
            "electionTime" : Timestamp(1515056187, 1),
            "electionDate" : ISODate("2018-01-04T08:56:27Z"),
            "configVersion" : 1,
            "self" : true
        },
        {
            "_id" : 1,
            "name" : "10.0.0.134:28018", #ip port "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY", #從節點 "uptime" : 635,
            "optime" : {
                "ts" : Timestamp(1515056188, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T08:56:28Z"),
            "lastHeartbeat" : ISODate("2018-01-04T09:06:52.289Z"),
            "lastHeartbeatRecv" : ISODate("2018-01-04T09:06:51.722Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "10.0.0.134:28017",
            "configVersion" : 1
        },
        {
            "_id" : 2,
            "name" : "10.0.0.134:28019", #ip port "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY", #從節點 "uptime" : 635,
            "optime" : {
                "ts" : Timestamp(1515056188, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T08:56:28Z"),
            "lastHeartbeat" : ISODate("2018-01-04T09:06:52.289Z"),
            "lastHeartbeatRecv" : ISODate("2018-01-04T09:06:51.601Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "10.0.0.134:28017",
            "configVersion" : 1
        }
    ],
    "ok" : 1
}

 

 

 

#查看當前是否為主節點

 

 

#主節點檢測
my_repl:PRIMARY>  rs.isMaster();
{
    "hosts" : [
        "10.0.0.134:28017",
        "10.0.0.134:28018",
        "10.0.0.134:28019"
    ],
    "setName" : "my_repl",
    "setVersion" : 1,
    "ismaster" : true, #主節點 "secondary" : false,
    "primary" : "10.0.0.134:28017",
    "me" : "10.0.0.134:28017",
    "electionId" : ObjectId("7fffffff0000000000000001"),
    "maxBsonObjectSize" : 16777216,
    "maxMessageSizeBytes" : 48000000,
    "maxWriteBatchSize" : 1000,
    "localTime" : ISODate("2018-01-04T09:11:15.204Z"),
    "maxWireVersion" : 4,
    "minWireVersion" : 0,
    "ok" : 1
}

#從節點檢測
[mongod@mongo ~]$ mongo --port=28018
MongoDB shell version: 3.2.8
connecting to: 127.0.0.1:28018/test
my_repl:SECONDARY> rs.isMaster()
{
    "hosts" : [
        "10.0.0.134:28017",
        "10.0.0.134:28018",
        "10.0.0.134:28019"
    ],
    "setName" : "my_repl", 
    "setVersion" : 1,
    "ismaster" : false, 
    "secondary" : true, #從節點 "primary" : "10.0.0.134:28017",
    "me" : "10.0.0.134:28018",
    "maxBsonObjectSize" : 16777216,
    "maxMessageSizeBytes" : 48000000,
    "maxWriteBatchSize" : 1000,
    "localTime" : ISODate("2018-01-04T09:11:40.092Z"),
    "maxWireVersion" : 4,
    "minWireVersion" : 0,
    "ok" : 1
}

 

 

#在主節點上添加節點

my_repl:PRIMARY> rs.add ("10.0.0.134:28020") #添加從節點
{ "ok" : 1 }
my_repl:PRIMARY> rs.status()
{
    "set" : "my_repl",
    "date" : ISODate("2018-01-04T09:16:33.144Z"),
    "myState" : 1,
    "term" : NumberLong(1),
    "heartbeatIntervalMillis" : NumberLong(2000),
    "members" : [
        {
            "_id" : 0,
            "name" : "10.0.0.134:28017",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 1353,
            "optime" : {
                "ts" : Timestamp(1515057249, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T09:14:09Z"),
            "electionTime" : Timestamp(1515056187, 1),
            "electionDate" : ISODate("2018-01-04T08:56:27Z"),
            "configVersion" : 2,
            "self" : true
        },
        {
            "_id" : 1,
            "name" : "10.0.0.134:28018",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 1216,
            "optime" : {
                "ts" : Timestamp(1515057249, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T09:14:09Z"),
            "lastHeartbeat" : ISODate("2018-01-04T09:16:31.632Z"),
            "lastHeartbeatRecv" : ISODate("2018-01-04T09:16:31.693Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "10.0.0.134:28017",
            "configVersion" : 2
        },
        {
            "_id" : 2,
            "name" : "10.0.0.134:28019",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 1216,
            "optime" : {
                "ts" : Timestamp(1515057249, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T09:14:09Z"),
            "lastHeartbeat" : ISODate("2018-01-04T09:16:31.632Z"),
            "lastHeartbeatRecv" : ISODate("2018-01-04T09:16:31.693Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "10.0.0.134:28017",
            "configVersion" : 2
        },
        {
            "_id" : 3,
            "name" : "10.0.0.134:28020",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY", #從節點10.0.0.134：28020 "uptime" : 143,
            "optime" : {
                "ts" : Timestamp(1515057249, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T09:14:09Z"),
            "lastHeartbeat" : ISODate("2018-01-04T09:16:31.647Z"),
            "lastHeartbeatRecv" : ISODate("2018-01-04T09:16:30.645Z"),
            "pingMs" : NumberLong(0),
            "configVersion" : 2
        }
    ],
    "ok" : 1
}

 

 

#刪除節點

my_repl:PRIMARY> rs.remove("10.0.0.134:28020") #刪除從節點
{ "ok" : 1 }
my_repl:PRIMARY> rs.status()
{
    "set" : "my_repl",
    "date" : ISODate("2018-01-04T09:18:10.582Z"),
    "myState" : 1,
    "term" : NumberLong(1),
    "heartbeatIntervalMillis" : NumberLong(2000),
    "members" : [
        {
            "_id" : 0,
            "name" : "10.0.0.134:28017",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 1450,
            "optime" : {
                "ts" : Timestamp(1515057484, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T09:18:04Z"),
            "electionTime" : Timestamp(1515056187, 1),
            "electionDate" : ISODate("2018-01-04T08:56:27Z"),
            "configVersion" : 3,
            "self" : true
        },
        {
            "_id" : 1,
            "name" : "10.0.0.134:28018",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 1313,
            "optime" : {
                "ts" : Timestamp(1515057484, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T09:18:04Z"),
            "lastHeartbeat" : ISODate("2018-01-04T09:18:10.231Z"),
            "lastHeartbeatRecv" : ISODate("2018-01-04T09:18:10.241Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "10.0.0.134:28017",
            "configVersion" : 3
        },
        {
            "_id" : 2,
            "name" : "10.0.0.134:28019",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 1313,
            "optime" : {
                "ts" : Timestamp(1515057484, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T09:18:04Z"),
            "lastHeartbeat" : ISODate("2018-01-04T09:18:10.231Z"),
            "lastHeartbeatRecv" : ISODate("2018-01-04T09:18:10.243Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "10.0.0.134:28017",
            "configVersion" : 3
        }
    ],
    "ok" : 1
}

 

 #添加仲裁節點

my_repl:PRIMARY> rs.addArb("10.0.0.134:28020");#添加仲裁節點
{ "ok" : 1 }
my_repl:PRIMARY> rs.status();
{
    "set" : "my_repl",
    "date" : ISODate("2018-01-04T09:19:32.814Z"),
    "myState" : 1,
    "term" : NumberLong(1),
    "heartbeatIntervalMillis" : NumberLong(2000),
    "members" : [
        {
            "_id" : 0,
            "name" : "10.0.0.134:28017",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 1532,
            "optime" : {
                "ts" : Timestamp(1515057570, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T09:19:30Z"),
            "electionTime" : Timestamp(1515056187, 1),
            "electionDate" : ISODate("2018-01-04T08:56:27Z"),
            "configVersion" : 6,
            "self" : true
        },
        {
            "_id" : 1,
            "name" : "10.0.0.134:28018",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 1395,
            "optime" : {
                "ts" : Timestamp(1515057570, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T09:19:30Z"),
            "lastHeartbeat" : ISODate("2018-01-04T09:19:30.915Z"),
            "lastHeartbeatRecv" : ISODate("2018-01-04T09:19:30.926Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "10.0.0.134:28017",
            "configVersion" : 5
        },
        {
            "_id" : 2,
            "name" : "10.0.0.134:28019",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 1395,
            "optime" : {
                "ts" : Timestamp(1515057534, 1),
                "t" : NumberLong(1)
            },
            "optimeDate" : ISODate("2018-01-04T09:18:54Z"),
            "lastHeartbeat" : ISODate("2018-01-04T09:19:30.902Z"),
            "lastHeartbeatRecv" : ISODate("2018-01-04T09:19:30.922Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "10.0.0.134:28017",
            "configVersion" : 5
        },
        {
            "_id" : 4,
            "name" : "10.0.0.134:28020",
            "health" : 1,
            "state" : 7,
            "stateStr" : "ARBITER", #仲裁節點 "uptime" : 34,
            "lastHeartbeat" : ISODate("2018-01-04T09:19:30.903Z"),
            "lastHeartbeatRecv" : ISODate("2018-01-04T09:19:30.924Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "10.0.0.134:28019",
            "configVersion" : 5
        }
    ],
    "ok" : 1
}

 

 #主、從、仲裁節點對比

#主節點操作
[mongod@mongo ~]$ mongo --port=28017
MongoDB shell version: 3.2.8
connecting to: 127.0.0.1:28017/test
my_repl:PRIMARY> use test
switched to db test
my_repl:PRIMARY> db.anyux.insert([{"language":"C"},{"language":"C++"}]) #插入數據
BulkWriteResult({
    "writeErrors" : [ ],
    "writeConcernErrors" : [ ],
    "nInserted" : 2,
    "nUpserted" : 0,
    "nMatched" : 0,
    "nModified" : 0,
    "nRemoved" : 0,
    "upserted" : [ ]
})
my_repl:PRIMARY> db.anyux.find().pretty() 　　　　　　　　　　　　　　　　　　#主節點顯示數據
{ "_id" : ObjectId("5a4df337c702312dedac9176"), "language" : "C" }
{ "_id" : ObjectId("5a4df337c702312dedac9177"), "language" : "C++" }

#從節點操作
MongoDB shell version: 3.2.8
connecting to: 127.0.0.1:28018/test
my_repl:SECONDARY> use test
my_repl:SECONDARY> rs.slaveOk();
my_repl:SECONDARY> db.anyux.find().pretty()                             #從節點顯示數據
{ "_id" : ObjectId("5a4df337c702312dedac9176"), "language" : "C" }
{ "_id" : ObjectId("5a4df337c702312dedac9177"), "language" : "C++" }

#仲裁節點
[mongod@mongo ~]$ mongo --port=28020
MongoDB shell version: 3.2.8
connecting to: 127.0.0.1:28020/test
my_repl:ARBITER> rs.slaveOk();
my_repl:ARBITER> show dbs;
local  0.000GB
test   0.000GB
my_repl:ARBITER> db.anyux.find().pretty();                               #仲裁節點不會存儲數據
Error: error: { "ok" : 0, "errmsg" : "node is recovering", "code" : 13436 }