mongodb集群配置主從模式

   

• 測試環境

  操作系統：CentOS 7.2 最小化安裝

  主服務器IP地址：192.168.197.21 master-node

  從服務器IP地址：192.168.197.22 slave-node

  關閉selinux，關閉防火牆。

  Mongodb版本：mongodb-linux-x86_64-3.4.10.tgz

• 上傳mongodb包到/software目錄下，然后解壓縮該包

  [root@localhost software]# tar -zxvf mongodb-linux-x86_64-3.4.10.tgz

• 移動解壓縮之后的文件至/usr/local/mongodb目錄

  [root@localhost software]# mv mongodb-linux-x86_64-3.4.10 /usr/local/mongodb

• 在mongodb下面創建data目錄和logs目錄，用於存放data和logs

  [root@localhost local]# mkdir -p /usr/local/mongodb/data

  [root@localhost local]# mkdir -p /usr/local/mongodb/logs

• 增加環境變量，並使環境變量生效

  [root@localhost data]# vi /etc/profile

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

  [root@localhost data]# source /etc/profile

• 創建mongodb.conf文件並寫入一下內容

  [root@localhost data]# touch /usr/local/mongodb/bin/mongodb.conf

  [root@localhost data]# vi /usr/local/mongodb/bin/mongodb.conf

• 主服務器配置

  [root@master-node software]# more /usr/local/mongodb/bin/mongodb.conf

  port=27017

  dbpath= /usr/local/mongodb/data

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

  logappend=true

  fork=true

  maxConns=100

  noauth=true

  journal=true

  storageEngine=wiredTiger

  bind_ip = 192.168.197.21

  master=true

• 從服務器配置

  [root@slave-node software]# more /usr/local/mongodb/bin/mongodb.conf

  port=27017

  dbpath= /usr/local/mongodb/data

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

  logappend=true

  fork=true

  maxConns=100

  noauth=true

  slave=true

  journal=true

  storageEngine=wiredTiger

  bind_ip = 192.168.197.22

  source=192.168.197.21:27017

• 使用配置文件啟動兩台服務器上的數據庫

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

• 在主服務器上登陸數據庫創建testa數據庫，並寫入20條數據

  [root@master-node software]# mongo 192.168.197.21:27017

  MongoDB shell version v3.4.10

  connecting to: 192.168.197.21:27017

  MongoDB server version: 3.4.10

  Server has startup warnings:

  2019-02-10T21:38:04.484-0500 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.

  2019-02-10T21:38:04.484-0500 I CONTROL [initandlisten]

  2019-02-10T21:38:04.485-0500 I CONTROL [initandlisten]

  2019-02-10T21:38:04.485-0500 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.

  2019-02-10T21:38:04.485-0500 I CONTROL [initandlisten] ** We suggest setting it to 'never'

  2019-02-10T21:38:04.485-0500 I CONTROL [initandlisten]

  2019-02-10T21:38:04.485-0500 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.

  2019-02-10T21:38:04.485-0500 I CONTROL [initandlisten] ** We suggest setting it to 'never'

  2019-02-10T21:38:04.485-0500 I CONTROL [initandlisten]

  > use testa

  switched to db testa

  > function add(){var i = 0;for(;i<20;i++){db.persons.insert({"nameA":"li"+i})}}

  > add()

  > db.persons.find()

  { "_id" : ObjectId("5c61272206144917c514f1a3"), "nameA" : "li0" }

  { "_id" : ObjectId("5c61272206144917c514f1a4"), "nameA" : "li1" }

  { "_id" : ObjectId("5c61272206144917c514f1a5"), "nameA" : "li2" }

  { "_id" : ObjectId("5c61272206144917c514f1a6"), "nameA" : "li3" }

  { "_id" : ObjectId("5c61272206144917c514f1a7"), "nameA" : "li4" }

  { "_id" : ObjectId("5c61272206144917c514f1a8"), "nameA" : "li5" }

  { "_id" : ObjectId("5c61272206144917c514f1a9"), "nameA" : "li6" }

  { "_id" : ObjectId("5c61272206144917c514f1aa"), "nameA" : "li7" }

  { "_id" : ObjectId("5c61272206144917c514f1ab"), "nameA" : "li8" }

  { "_id" : ObjectId("5c61272206144917c514f1ac"), "nameA" : "li9" }

  { "_id" : ObjectId("5c61272206144917c514f1ad"), "nameA" : "li10" }

  { "_id" : ObjectId("5c61272206144917c514f1ae"), "nameA" : "li11" }

  { "_id" : ObjectId("5c61272206144917c514f1af"), "nameA" : "li12" }

  { "_id" : ObjectId("5c61272206144917c514f1b0"), "nameA" : "li13" }

  { "_id" : ObjectId("5c61272206144917c514f1b1"), "nameA" : "li14" }

  { "_id" : ObjectId("5c61272206144917c514f1b2"), "nameA" : "li15" }

  { "_id" : ObjectId("5c61272206144917c514f1b3"), "nameA" : "li16" }

  { "_id" : ObjectId("5c61272206144917c514f1b4"), "nameA" : "li17" }

  { "_id" : ObjectId("5c61272206144917c514f1b5"), "nameA" : "li18" }

  { "_id" : ObjectId("5c61272206144917c514f1b6"), "nameA" : "li19" }

• 登陸從服務器的數據庫查看數據是否同步過來

  [root@slave-node software]# mongo 192.168.197.22:27017

  MongoDB shell version v3.4.10

  connecting to: 192.168.197.22:27017

  MongoDB server version: 3.4.10

  Server has startup warnings:

  2019-02-10T21:43:16.796-0500 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.

  2019-02-10T21:43:16.796-0500 I CONTROL [initandlisten]

  2019-02-10T21:43:16.796-0500 I CONTROL [initandlisten]

  2019-02-10T21:43:16.796-0500 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.

  2019-02-10T21:43:16.796-0500 I CONTROL [initandlisten] ** We suggest setting it to 'never'

  2019-02-10T21:43:16.796-0500 I CONTROL [initandlisten]

  2019-02-10T21:43:16.796-0500 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.

  2019-02-10T21:43:16.796-0500 I CONTROL [initandlisten] ** We suggest setting it to 'never'

  2019-02-10T21:43:16.796-0500 I CONTROL [initandlisten]

  > show dbs

  2019-02-11T02:43:26.999-0500 E QUERY [thread1] Error: listDatabases failed:{

  "ok" : 0,

  "errmsg" : "not master and slaveOk=false",

  "code" : 13435,

  "codeName" : "NotMasterNoSlaveOk"

  } :

  _getErrorWithCode@src/mongo/shell/utils.js:25:13

  Mongo.prototype.getDBs@src/mongo/shell/mongo.js:62:1

  shellHelper.show@src/mongo/shell/utils.js:781:19

  shellHelper@src/mongo/shell/utils.js:671:15

  @(shellhelp2):1:1

  > rs.slaveOk()

  > show dbs

  admin 0.000GB

  local 0.000GB

  master_slave 0.000GB

  testa 0.000GB

  > use testa

  switched to db testa

  > db.persons.find()

  { "_id" : ObjectId("5c61272206144917c514f1a3"), "nameA" : "li0" }

  { "_id" : ObjectId("5c61272206144917c514f1a4"), "nameA" : "li1" }

  { "_id" : ObjectId("5c61272206144917c514f1a5"), "nameA" : "li2" }

  { "_id" : ObjectId("5c61272206144917c514f1a6"), "nameA" : "li3" }

  { "_id" : ObjectId("5c61272206144917c514f1a7"), "nameA" : "li4" }

  { "_id" : ObjectId("5c61272206144917c514f1a8"), "nameA" : "li5" }

  { "_id" : ObjectId("5c61272206144917c514f1a9"), "nameA" : "li6" }

  { "_id" : ObjectId("5c61272206144917c514f1aa"), "nameA" : "li7" }

  { "_id" : ObjectId("5c61272206144917c514f1ab"), "nameA" : "li8" }

  { "_id" : ObjectId("5c61272206144917c514f1ac"), "nameA" : "li9" }

  { "_id" : ObjectId("5c61272206144917c514f1ad"), "nameA" : "li10" }

  { "_id" : ObjectId("5c61272206144917c514f1ae"), "nameA" : "li11" }

  { "_id" : ObjectId("5c61272206144917c514f1af"), "nameA" : "li12" }

  { "_id" : ObjectId("5c61272206144917c514f1b0"), "nameA" : "li13" }

  { "_id" : ObjectId("5c61272206144917c514f1b1"), "nameA" : "li14" }

  { "_id" : ObjectId("5c61272206144917c514f1b2"), "nameA" : "li15" }

  { "_id" : ObjectId("5c61272206144917c514f1b3"), "nameA" : "li16" }

  { "_id" : ObjectId("5c61272206144917c514f1b4"), "nameA" : "li17" }

  { "_id" : ObjectId("5c61272206144917c514f1b5"), "nameA" : "li18" }

  { "_id" : ObjectId("5c61272206144917c514f1b6"), "nameA" : "li19" }

• 關於報錯

  如果在slave-node節點上的數據庫中查看，有報錯："errmsg" : "not master and slaveOk=false"！！！

  首先這是正常的，因為SECONDARY是不允許讀寫的， 在寫多讀少的應用中，使用Replica Sets來實現讀寫分離。通過在連接時指定或者在主庫指定slaveOk，由Secondary來分擔讀的壓力，Primary只承擔寫操作。對於replica set 中的secondary 節點默認是不可讀的。

  解決辦法：在slave-node節點數據庫中執行"rs.slaveOk();"命令即可

  在slave-node節點數據庫中發現已經同步過來了testa庫的20條數據，說明mongodb的主從復制環境已經成功了！當配置完主從服務器后，一但主服務器上的數據發生變化，從服務器也會發生變化。

• 設置mongodb的開機啟動。

  首先要在系統服務目錄下創建啟動文件mongodb.servicer然后寫入一下內容

  [root@localhost system]# cd /lib/systemd/system

  [root@localhost system]# vi mongodb.service

  [Unit]

  Description=mongodb

  After=network.target remote-fs.target nss-lookup.target

  [Service]

  Type=forking

  ExecStart=/usr/local/mongodb/bin/mongod -f /usr/local/mongodb/bin/mongodb.conf

  ExecReload=/bin/kill -s HUP $MAINPID

  ExecStop=/usr/local/mongodb/bin/mongod --shutdown

  PrivateTmp=true

  [Install]

  WantedBy=multi-user.target

  注冊到開機啟動

  [root@localhost system]# systemctl enable mongodb.service

  Created symlink from /etc/systemd/system/multi-user.target.wants/mongodb.service to /usr/lib/systemd/system/mongodb.service.

  啟動

  systemctl start mongodb.service

  關閉

  systemctl stop mongodb.service