在CentOS7上部署MongoDB複製集和複製集的管理維護
MongoDB複製集的概述
複製集是額外的數據副本，是跨多個服務器同步數據的過程，複製集提供了冗餘並增長了數據可用性，經過複製集能夠對硬件故障和中斷的服務進行恢復。mongodb
複製集工做原理
- MongoDB的複製集至少須要兩個節點。其中一個是主節點（primary），負責處理客戶端的請求，其他都是從節點（Secondary）,負責複製主節點上的數據。
- MongoDB各個節點常見的搭配方式爲：一主一從或一主多從。主節點記錄其上的全部操做到oplog中，從節點按期輪詢主節點獲取這些操做，而後對本身的數副本執行這些操做，從而保證從節點的數據與主節點一致。
複製集的特色
- N個節點的羣集
- 任何節點可做爲主節點
- 全部寫入操做都在主節點上
- 自動故障轉移
- 自動恢復
MongoDB複製集部署
1.配置複製集shell
（1）建立數據文件和日誌文件存儲路徑數據庫
[root@localhost ~]# mkdir -p /data/mongodb/mongodb{2,3,4}
[root@localhost ~]# cd /data/mongodb/
[root@localhost mongodb]# mkdir logs
[root@localhost mongodb]# touch logs/mongodb{2,3,4}.log
[root@localhost mongodb]# cd logs/
[root@localhost logs]# ls
mongodb2.log mongodb3.log mongodb4.log
[root@localhost logs]# chmod 777 *.log
（2）編輯4個MongoDB實例的配置文件vim
先編輯Mongodb的配置文件，配置replSet參數值都爲kgcrs,並複製3份，具體操做以下：服務器
[root@localhost etc]# vim mongod.conf
path: /var/log/mongodb/mongod.log
# Where and how to store data.
storage:
dbPath: /var/lib/mongo
journal:
enabled: true
# engine:
# mmapv1:
# wiredTiger:
# how the process runs
processManagement:
fork: true # fork and run in background
pidFilePath: /var/run/mongodb/mongod.pid # location of pidfile
timeZoneInfo: /usr/share/zoneinfo
# network interfaces
net:
port: 27017
bindIp: 0.0.0.0 # Listen to local interface only, comment to listen on all interfaces.
#security:
#operationProfiling:
replication:
replSetName: kgcrs
#sharding:
## Enterprise-Only Options
#auditLog:
#snmp:
而後將mongodb2.conf中的port參數配置爲27018,mongodb3.conf中的port參數配置爲27019，mongodb4.conf中的port參數配置爲27020。一樣也將dbpath和logpath參數修改成對應的路徑值。app
（3）啓動4個MongoDB節點實列並查看進程信息tcp
[root@localhost etc]# mongod -f /etc/mongod.conf --shutdown //先關閉// [root@localhost etc]# mongod -f /etc/mongod.conf //再開啓// [root@localhost etc]# mongod -f /etc/mongod2.conf [root@localhost etc]# mongod -f /etc/mongod3.conf [root@localhost etc]# mongod -f /etc/mongod4.conf [root@localhost etc]# netstat -ntap | grep mongod tcp 0 0 0.0.0.0:27019 0.0.0.0:* LISTEN 17868/mongod tcp 0 0 0.0.0.0:27020 0.0.0.0:* LISTEN 17896/mongod tcp 0 0 0.0.0.0:27017 0.0.0.0:* LISTEN 17116/mongod tcp 0 0 0.0.0.0:27018 0.0.0.0:* LISTEN 17413/mongod
（4）配置三個節點的複製集ide
[root@localhost etc]# mongo
> rs.status() //查看複製集//
{
"info" : "run rs.initiate(...) if not yet done for the set",
"ok" : 0,
"errmsg" : "no replset config has been received",
"code" : 94,
"codeName" : "NotYetInitialized",
"$clusterTime" : {
"clusterTime" : Timestamp(0, 0),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
> cfg={"_id":"kgcrs","members":[{"_id":0,"host":"192.168.126.132:27017"},{"_id":1,"host":"192.168.126.132:27018"},{"_id":2,"host":"192.168.126.132:27019"}]} //添加複製集//
{
"_id" : "kgcrs",
"members" : [
{
"_id" : 0,
"host" : "192.168.126.132:27017"
},
{
"_id" : 1,
"host" : "192.168.126.132:27018"
},
{
"_id" : 2,
"host" : "192.168.126.132:27019"
}
]
}
> rs.initiate(cfg) //初始化配置時保證從節點沒有數據//
（5）查看複製集狀態prototype
啓動複製集後，再次經過rs.status()命令查看複製集的完整狀態信息日誌
kgcrs:SECONDARY> rs.status()
{
"set" : "kgcrs",
"date" : ISODate("2018-07-17T07:18:52.047Z"),
"myState" : 1,
"term" : NumberLong(1),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"heartbeatIntervalMillis" : NumberLong(2000),
"optimes" : {
"lastCommittedOpTime" : {
"ts" : Timestamp(1531811928, 1),
"t" : NumberLong(1)
},
"readConcernMajorityOpTime" : {
"ts" : Timestamp(1531811928, 1),
"t" : NumberLong(1)
},
"appliedOpTime" : {
"ts" : Timestamp(1531811928, 1),
"t" : NumberLong(1)
},
"durableOpTime" : {
"ts" : Timestamp(1531811928, 1),
"t" : NumberLong(1)
}
},
"members" : [
{
"_id" : 0,
"name" : "192.168.126.132:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY", //主節點//
"uptime" : 2855,
"optime" : {
"ts" : Timestamp(1531811928, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2018-07-17T07:18:48Z"),
"syncingTo" : "",
"syncSourceHost" : "",
"syncSourceId" : -1,
"infoMessage" : "could not find member to sync from",
"electionTime" : Timestamp(1531811847, 1),
"electionDate" : ISODate("2018-07-17T07:17:27Z"),
"configVersion" : 1,
"self" : true,
"lastHeartbeatMessage" : ""
},
{
"_id" : 1,
"name" : "192.168.126.132:27018",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY", //從節點//
"uptime" : 95,
"optime" : {
"ts" : Timestamp(1531811928, 1),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1531811928, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2018-07-17T07:18:48Z"),
"optimeDurableDate" : ISODate("2018-07-17T07:18:48Z"),
"lastHeartbeat" : ISODate("2018-07-17T07:18:51.208Z"),
"lastHeartbeatRecv" : ISODate("2018-07-17T07:18:51.720Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "192.168.126.132:27017",
"syncSourceHost" : "192.168.126.132:27017",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 1
},
{
"_id" : 2,
"name" : "192.168.126.132:27019",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY", //從節點//
"uptime" : 95,
"optime" : {
"ts" : Timestamp(1531811928, 1),
"t" : NumberLong(1)
},
"optimeDurable" : {
"ts" : Timestamp(1531811928, 1),
"t" : NumberLong(1)
},
"optimeDate" : ISODate("2018-07-17T07:18:48Z"),
"optimeDurableDate" : ISODate("2018-07-17T07:18:48Z"),
"lastHeartbeat" : ISODate("2018-07-17T07:18:51.208Z"),
"lastHeartbeatRecv" : ISODate("2018-07-17T07:18:51.822Z"),
"pingMs" : NumberLong(0),
"lastHeartbeatMessage" : "",
"syncingTo" : "192.168.126.132:27017",
"syncSourceHost" : "192.168.126.132:27017",
"syncSourceId" : 0,
"infoMessage" : "",
"configVersion" : 1
}
],
"ok" : 1,
"operationTime" : Timestamp(1531811928, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1531811928, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
其中，health爲1表明健康，0表明宕機。state爲1表明主節點，爲2表明從節點。
在複製集初始化配置時要保證從節點上沒有數據
MongoDB複製集切換
MongoDB複製集能夠實現羣集的高可用，當其中主節點出現故障時會自動切換到其餘節點。也可手動進行復制集的主從切換。
1.故障轉移切換
[root@localhost etc]# ps aux | grep mongod //查看進程//
root 17116 1.2 5.8 1546916 58140 ? Sl 14:31 0:51 mongod -f /etc/mongod.conf
root 17413 1.0 5.7 1445624 57444 ? Sl 14:34 0:39 mongod -f /etc/mongod2.conf
root 17868 1.2 5.5 1446752 55032 ? Sl 15:05 0:23 mongod -f /etc/mongod3.conf
root 17896 0.8 4.7 1037208 47552 ? Sl 15:05 0:16 mongod -f /etc/mongod4.conf
root 18836 0.0 0.0 112676 980 pts/1 S+ 15:38 0:00 grep --color=auto mongod
[root@localhost etc]# kill -9 17116 ///殺死27017進程//
[root@localhost etc]# ps aux | grep mongod
root 17413 1.0 5.7 1453820 57456 ? Sl 14:34 0:40 mongod -f /etc/mongod2.conf
root 17868 1.2 5.5 1454948 55056 ? Sl 15:05 0:24 mongod -f /etc/mongod3.conf
root 17896 0.8 4.7 1037208 47552 ? Sl 15:05 0:16 mongod -f /etc/mongod4.conf
root 18843 0.0 0.0 112676 976 pts/1 R+ 15:38 0:00 grep --color=auto mongod
[root@localhost etc]# mongo --port 27019
kgcrs:PRIMARY> rs.status()
"members" : [
{
"_id" : 0,
"name" : "192.168.126.132:27017",
"health" : 0, //宕機狀態//
"state" : 8,
"stateStr" : "(not reachable/healthy)",
"uptime" : 0,
"optime" : {
"ts" : Timestamp(0, 0),
"t" : NumberLong(-1)
{
"_id" : 1,
"name" : "192.168.126.132:27018",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY", //從節點//
"uptime" : 1467,
"optime" : {
"ts" : Timestamp(1531813296, 1),
"t" : NumberLong(2)
},
"optimeDurable" : {
"ts" : Timestamp(1531813296, 1),
"t" : NumberLong(2)
},
{
"_id" : 2,
"name" : "192.168.126.132:27019",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY", //主節點//
"uptime" : 2178,
"optime" : {
"ts" : Timestamp(1531813296, 1),
"t" : NumberLong(2)
}
2.手動進行主從切換
kgcrs:PRIMARY> rs.freeze(30) //暫停30s不參與選舉
kgcrs:PRIMARY> rs.stepDown(60,30) //交出主節點位置，維持從節點狀態很多於60秒，等待30秒使主節點和從節點日誌同步
2018-07-17T15:46:19.079+0800 E QUERY [thread1] Error: error doing query: failed: network error while attempting to run command 'replSetStepDown' on host '127.0.0.1:27019' :
DB.prototype.runCommand@src/mongo/shell/db.js:168:1
DB.prototype.adminCommand@src/mongo/shell/db.js:186:16
rs.stepDown@src/mongo/shell/utils.js:1341:12
@(shell):1:1
2018-07-17T15:46:19.082+0800 I NETWORK [thread1] trying reconnect to 127.0.0.1:27019 (127.0.0.1) failed
2018-07-17T15:46:19.085+0800 I NETWORK [thread1] reconnect 127.0.0.1:27019 (127.0.0.1) ok
kgcrs:SECONDARY> //交出主節點後立馬變成從節點//
kgcrs:SECONDARY> rs.status()
"_id" : 0,
"name" : "192.168.126.132:27017",
"health" : 0, //宕機狀態//
"state" : 8,
"stateStr" : "(not reachable/healthy)",
"uptime" : 0,
"optime" : {
"ts" : Timestamp(0, 0),
"t" : NumberLong(-1)
},
{
"_id" : 1,
"name" : "192.168.126.132:27018",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY", //主節點狀態//
"uptime" : 1851,
"optime" : {
"ts" : Timestamp(1531813679, 1),
"t" : NumberLong(3)
{
"_id" : 2,
"name" : "192.168.126.132:27019",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY", //從節點狀態//
"uptime" : 2563,
"optime" : {
"ts" : Timestamp(1531813689, 1),
"t" : NumberLong(3)
MongoDB複製集的選舉原理
節點類型分爲標準節點（host）、被動節點（passive）和仲裁節點（arbiter）。
- 只有標準節點可能被選舉爲活躍（primary）節點，有選舉權。被動節點有完整副本，不可能成爲活躍節點，有選舉權。仲裁節點不復制數據，不可能成爲活躍節點，只有選舉權。
- 標準節點與被動節點的區別：priority值高者是標準節點，低者爲被動節點。
- 選舉規則是票數高者獲勝，priority是優先權爲0~1000的值，至關於額外增長0~1000的票數。選舉結果：票數高者獲勝；若票數相同，數據新者獲勝。
1.配置複製集的優先級
1）從新配置4個節點的MongoDB複製集，設置兩個標準節點，一個被動節點和一個仲裁節點。
[root@localhost etc]# mongo
> cfg={"_id":"kgcrs","members":[{"_id":0,"host":"192.168.126.132:27017","priority":100},{"_id":1,"host":"192.168.126.132:27018","priority":100},{"_id":2,"host":"192.168.126.132:27019","priority":0},{"_id":3,"host":"192.168.126.132:27020","arbiterOnly":true}]}
> rs.initiate(cfg) //從新配置//
kgcrs:SECONDARY> rs.isMaster()
{
"hosts" : [ //標準節點//
"192.168.126.132:27017",
"192.168.126.132:27018"
],
"passives" : [ //被動節點//
"192.168.126.132:27019"
],
"arbiters" : [ //仲裁節點//
"192.168.126.132:27020"
2）模擬主節點故障
若是主節點出現故障，另外一個標準節點將會選舉成爲新的主節點
[root@localhost etc]# mongod -f /etc/mongod.conf --shutdown //標準節點27017//
[root@localhost etc]# mongo --port 27018 //此時會選舉第二個標準節點爲主節點//
kgcrs:PRIMARY> rs.status()
"_id" : 0,
"name" : "192.168.126.132:27017",
"health" : 0, //宕機狀態//
"state" : 8,
"stateStr" : "(not reachable/healthy)",
"uptime" : 0,
"optime" : {
"ts" : Timestamp(0, 0),
"t" : NumberLong(-1)
"_id" : 1,
"name" : "192.168.126.132:27018",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY", //標準節點//
"uptime" : 879,
"optime" : {
"ts" : Timestamp(1531817473, 1),
"t" : NumberLong(2)
"_id" : 2,
"name" : "192.168.126.132:27019",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY", //被動節點//
"uptime" : 569,
"optime" : {
"ts" : Timestamp(1531817473, 1),
"t" : NumberLong(2)
"_id" : 3,
"name" : "192.168.126.132:27020",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER", //仲裁節點//
"uptime" : 569,
3）模擬全部標準節點出現故障
全部標準節點都出現故障，被動節點也不能成爲主節點
[root@localhost etc]# mongod -f /etc/mongod2.conf --shutdown //關閉標準節點27018//
[root@localhost etc]# mongo --port 27019
kgcrs:SECONDARY> rs.status()
"_id" : 0,
"name" : "192.168.126.132:27017",
"health" : 0, //宕機狀態//
"state" : 8,
"stateStr" : "(not reachable/healthy)",
"uptime" : 0,
"_id" : 1,
"name" : "192.168.126.132:27018",
"health" : 0, //宕機狀態//
"state" : 8,
"stateStr" : "(not reachable/healthy)",
"uptime" : 0,
"_id" : 2,
"name" : "192.168.126.132:27019",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY", //被動節點//
"uptime" : 1403,
"_id" : 3,
"name" : "192.168.126.132:27020",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER", //仲裁節點//
MongoDB複製集管理
1.配置容許在從節點讀取數據
默認MongoDB複製集的從節點不能讀取數據，可使用rs.slaveOk()命令容許可以在從節點讀取數據。
[root@localhost etc]# mongo --port 27017
kgcrs:SECONDARY> show dbs //讀取不到數據庫信息//
2018-07-17T17:11:31.570+0800 E QUERY [thread1] Error: listDatabases failed:{
"operationTime" : Timestamp(1531818690, 1),
"ok" : 0,
"errmsg" : "not master and slaveOk=false",
"code" : 13435,
"codeName" : "NotMaste
kgcrs:SECONDARY> rs.slaveOk()
kgcrs:SECONDARY> show dbs
admin 0.000GB
config 0.000GB
local 0.000GB
2.查看複製狀態信息
可使用 rs.printReplicationInfo()和rs.printSlaveReplicationInfo()命令查看複製集狀態。
kgcrs:SECONDARY> rs.printReplicationInfo()
configured oplog size: 990MB
log length start to end: 2092secs (0.58hrs)
oplog first event time: Tue Jul 17 2018 16:41:48 GMT+0800 (CST)
oplog last event time: Tue Jul 17 2018 17:16:40 GMT+0800 (CST)
now: Tue Jul 17 2018 17:16:46 GMT+0800 (CST)
kgcrs:SECONDARY> rs.printSlaveReplicationInfo()
source: 192.168.126.132:27017
syncedTo: Tue Jul 17 2018 17:16:50 GMT+0800 (CST)
0 secs (0 hrs) behind the primary
source: 192.168.126.132:27019
syncedTo: Tue Jul 17 2018 17:16:50 GMT+0800 (CST)
0 secs (0 hrs) behind the primary
3.部署認證複製
kgcrs:PRIMARY> use admin
kgcrs:PRIMARY> db.createUser({"user":"root","pwd":"123","roles":["root"]})
[root@localhost ~]# vim /etc/mongod.conf //分別編輯四個配置文件//
....
security:
keyFile: /usr/bin/kgcrskey1 //驗證路徑//
clusterAuthMode: keyFile //驗證類型//
[root@localhost ~]# vim /etc/mongod2.conf
[root@localhost ~]# vim /etc/mongod3.conf
[root@localhost ~]# vim /etc/mongod4.conf
[root@localhost bin]# echo "kgcrs key"> kgcrskey1 //生成4個實例的密鑰文件//
[root@localhost bin]# echo "kgcrs key"> kgcrskey2
[root@localhost bin]# echo "kgcrs key"> kgcrskey3
[root@localhost bin]# echo "kgcrs key"> kgcrskey4
[root@localhost bin]# chmod 600 kgcrskey{1..4}
[root@localhost bin]# mongod -f /etc/mongod.conf //重啓4個實例//
[root@localhost bin]# mongod -f /etc/mongod2.conf
[root@localhost bin]# mongod -f /etc/mongod3.conf
[root@localhost bin]# mongod -f /etc/mongod4.conf
[root@localhost bin]# mongo --port 27017 //進入標準節點中//
kgcrs:PRIMARY> show dbs //沒法查看數據庫//
kgcrs:PRIMARY> rs.status() //沒法查看複製集//
kgcrs:PRIMARY> use admin //身份登陸驗證//
kgcrs:PRIMARY> db.auth("root","123")
kgcrs:PRIMARY> show dbs //能夠查看數據庫//
admin 0.000GB
config 0.000GB
local 0.000GB
kgcrs:PRIMARY> rs.status() //能夠查看複製集//
"_id" : 0,
"name" : "192.168.126.132:27017",
"health" : 1,
"state" : 1,
"stateStr" : "PRIMARY",
"uptime" : 411,
"_id" : 1,
"name" : "192.168.126.132:27018",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 324,
"_id" : 2,
"name" : "192.168.126.132:27019",
"health" : 1,
"state" : 2,
"stateStr" : "SECONDARY",
"uptime" : 305,
"_id" : 3,
"name" : "192.168.126.132:27020",
"health" : 1,
"state" : 7,
"stateStr" : "ARBITER",
"uptime" : 280,
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相關文章
- 1. mongodb複製集部署
- 2. MongoDB 複製集管理
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- 4. MongoDB 複製集
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