需要用到mongodb的时候单个实例肯定是不行的，挂了怎么办，那然后呢，跟mysql一样搞主从备份吗，是可以的mongodb这么弄，不过官网已经不推荐了这么干了，推荐使用副本集的模式，然后数据再大一点到TB级别就需要使用分片节点模式了，不过没那么大的数据没用到过，不管它。副本集就是每个都是副本，没有主的数据库，由副本之间选举主的mongodb，可以这样理解下，就是看到mysql没有keepalived的功能，mongodb学乖了，就引入了这个功能，并且有些地方还优化了下，蛮好用的。
mongodb副本集一般是基数个，偶数个也行的不过要引入调节器，还不如加一个mongo实例来的方便。
官网教程：https://docs.mongodb.com/manual/replication/index.html
配置副本集模式：
1、副本集之间加入认证需要生成keyfile：先生成keyfileopenssl rand -base64 90 > /var/lib/mongo/mongodb-keyfile然后复制到其它的服务器中scp /var/lib/mongo/mongodb-keyfile root@192.168.108.145: /var/lib/mongo/mongodb-keyfile两个服务器文件都要授权600chmod 600 /var/lib/mongo/mongodb-keyfile
2、修改/etc/mongod.conf服务器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 runsprocessManagement: fork: true # fork and run in background pidFilePath: /var/run/mongodb/mongod.pid # location of pidfile
# network interfacesnet: 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:
服务器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 runsprocessManagement: fork: true # fork and run in background pidFilePath: /var/run/mongodb/mongod.pid # location of pidfile
# network interfacesnet: 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:服务器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 runsprocessManagement: fork: true # fork and run in background pidFilePath: /var/run/mongodb/mongod.pid # location of pidfile
# network interfacesnet: 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个配置文件的副本集名称都设置成一样的，例如这里的water
3、设置admin用户名和密码use admindb.createUser({user:"admin",pwd:"password",roles:[{role:"root",db:"admin"}]})
以auth方式启动服务器2的mongodb，然后#初始化，哪个服务器先初始化就是主服务器 rs.initiate()use admindb.auth("admin","password");查看副本集节点状态rs.status()
添加副本集rs.add('192.168.108.145:27017') rs.add('192.168.108.145:27018')删除从服务器rs.remove('192.168.108.145:27017')rs.remove('192.168.108.145:27018')然后进入从服务器，查看备份数据rs.slaveOk()后面再进行查找操作
实验的效果是当从的mongodb挂了的时候是卜影响项目的运行的，当主的mongodb挂了的时候，会自动在两个从的mongodb上面推选出一个主的mongodb，，这里mongodb必须是基数个，不然不能推选出主的mongodb，其实配置起来不难，spring boot中配置mongodb把主从IP全都加进去就行了host="IP1,IP2,IP3:
大概就是这样了。
转载于:https://www.cnblogs.com/waterlufei/p/8135795.html
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