需要用到mongodb的時候單個實例肯定是不行的，掛了怎么辦，那然后呢，跟mysql一樣搞主從備份嗎，是可以的mongodb這么弄，不過官網已經不推薦了這么干了，推薦使用副本集的模式，然后數據再大一點到TB級別就需要使用分片節點模式了，不過沒那么大的數據沒用到過，不管它。副本集就是每個都是副本，沒有主的數據庫，由副本之間選舉主的mongodb，可以這樣理解下，就是看到mysql沒有keepalived的功能，mongodb學乖了，就引入了這個功能，並且有些地方還優化了下，蠻好用的。
mongodb副本集一般是基數個，偶數個也行的不過要引入調節器，還不如加一個mongo實例來的方便。
官網教程：https://docs.mongodb.com/manual/replication/index.html
配置副本集模式：
1、副本集之間加入認證
需要生成keyfile：
先生成keyfile
openssl rand -base64 90 > /var/lib/mongo/mongodb-keyfile
然后復制到其它的服務器中
scp /var/lib/mongo/mongodb-keyfile root@192.168.108.145: /var/lib/mongo/mongodb-keyfile
兩個服務器文件都要授權600
chmod 600 /var/lib/mongo/mongodb-keyfile
2、修改/etc/mongod.conf
服務器1的27017端口配置文件
# mongod.conf
# for documentation of all options, see:
# http://docs.mongodb.org/manual/reference/configuration-options/
# where to write logging data.
systemLog:
destination: file
logAppend: true
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
# network interfaces
net:
port: 27017
# bindIp: 127.0.0.1 # Listen to local interface only, comment to listen on all interfaces.
#security:
security:
keyFile: /var/lib/mongo/mongodb-keyfile
#operationProfiling:
#replication:
replication:
replSetName: water
#sharding:
## Enterprise-Only Options
#auditLog:
#snmp:
服務器1的27018配置文件
# mongod.conf
# for documentation of all options, see:
# http://docs.mongodb.org/manual/reference/configuration-options/
# where to write logging data.
systemLog:
destination: file
logAppend: true
path: /var/log/mongodb/mongod2.log
# Where and how to store data.
storage:
dbPath: /var/lib/mongo2
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
# network interfaces
net:
port: 27018
# bindIp: 0.0.0.0
# bindIp: 127.0.0.1 # Listen to local interface only, comment to listen on all interfaces.
#security:
security:
keyFile: /var/lib/mongo/mongodb-keyfile
#operationProfiling:
#replication:
replication:
replSetName: water
#sharding:
## Enterprise-Only Options
#auditLog:
#snmp:
服務器2的27017端口
# mongod.conf
# for documentation of all options, see:
# http://docs.mongodb.org/manual/reference/configuration-options/
# where to write logging data.
systemLog:
destination: file
logAppend: true
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
# network interfaces
net:
port: 27017
bindIp: 192.168.108.146
# bindIp: 127.0.0.1 # Listen to local interface only, comment to listen on all interfaces.
security:
authorization: enabled
keyFile: /var/lib/mongo/mongodb-keyfile
#security:
#operationProfiling:
#replication:
replication:
replSetName: water
#sharding:
## Enterprise-Only Options
#auditLog:
#snmp:
3個配置文件的副本集名稱都設置成一樣的，例如這里的water
3、設置admin用戶名和密碼
use admin
db.createUser({user:"admin",pwd:"password",roles:[{role:"root",db:"admin"}]})
以auth方式啟動服務器2的mongodb，然后
#初始化，哪個服務器先初始化就是主服務器
rs.initiate()
use admin
db.auth("admin","password");
查看副本集節點狀態
rs.status()
添加副本集
rs.add('192.168.108.145:27017')
rs.add('192.168.108.145:27018')
刪除從服務器
rs.remove('192.168.108.145:27017')
rs.remove('192.168.108.145:27018')
然后進入從服務器，查看備份數據
rs.slaveOk()
后面再進行查找操作
實驗的效果是當從的mongodb掛了的時候是卜影響項目的運行的，當主的mongodb掛了的時候，會自動在兩個從的mongodb上面推選出一個主的mongodb，，這里mongodb必須是基數個，不然不能推選出主的mongodb，其實配置起來不難，spring boot中配置mongodb把主從IP全都加進去就行了host="IP1,IP2,IP3:
大概就是這樣了。