在原有副本集的主節點進行操作：
1.1添加數據節點，
#在primary節點上執行
>rs.add( { host: '192.168.254.112:27017', priority: 9 } ) 這個節點被選為主primary
rs.status() ----驗證是否添加成功
查看是否有延遲，如下：
MongoDB Enterprise liuhe_rs:PRIMARY> rs.printSlaveReplicationInfo()
source: 10.9.21.178:27017
syncedTo: Tue Nov 26 2019 21:43:22 GMT+0800 (CST)
0 secs (0 hrs) behind the primary
source: 10.9.21.114:27017
syncedTo: Tue Nov 26 2019 21:43:22 GMT+0800 (CST)
0 secs (0 hrs) behind the primary
source: 10.9.21.115:27017
syncedTo: Tue Nov 26 2019 21:43:22 GMT+0800 (CST)
0 secs (0 hrs) behind the primary
如果新添加的狀態為STARTUP2,那么你可以重啟下新節點，
use admin
db.shutdownServer()
/usr/bin/mongodb/bin/mongod -f /etc/mongod.conf
#在primary節點上執行
>rs.add( { host: '192.168.254.112:27020', priority: 2 } )
rs.status() ----驗證是否添加成功
1.2刪除數據節點
rs.remove("10.9.21.115:27017");
rs.remove("192.168.1.112:27019");
再次查看發現沒有了115這個同步信息了
MongoDB Enterprise liuhe_rs:PRIMARY> rs.printSlaveReplicationInfo()
source: 10.9.21.178:27017
syncedTo: Tue Nov 26 2019 21:47:12 GMT+0800 (CST)
8 secs (0 hrs) behind the primary
source: 10.9.21.114:27017
syncedTo: Tue Nov 26 2019 21:47:12 GMT+0800 (CST)
8 secs (0 hrs) behind the primary
MongoDB Enterprise liuhe_rs:PRIMARY>
1.3添加仲裁節點
rs.addArb("10.9.21.112:27017");
或者
rs.add({host:"192.168.254.112:27018",arbiterOnly:true})
rs.status()
{
"_id" : 3,
"name" : "10.9.21.115:27017",
"health" : 1,
"state" : 7,
"stateStr" :
"ARBITER",
"uptime" : 165,
"lastHeartbeat" : ISODate("2019-11-26T13:55:21.391Z"),
"lastHeartbeatRecv" : ISODate("2019-11-26T13:55:21.150Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "",
"configVersion" : 6
}
1.4查看備份節點的復制信息
rs0:PRIMARY> db.printSlaveReplicationInfo()
source: 172.16.250.234:27017
syncedTo: Thu Nov 15 2018 11:08:36 GMT+0800 (CST)
0 secs (0 hrs) behind the primary
source: 172.16.250.240:27017
syncedTo: Thu Jan 01 1970 08:00:00 GMT+0800 (CST)
1542251316 secs (428403.14 hrs) behind the primary
副本集測試