Some points to pay attention to when closing mongodb services (as well as related commands when opening)

involves MongoDB All operations are used user_mongo User action

（ One ） Close the service

• You can use ps -ef | grep [ The service name ] Query related processes , And then use kill -2 [ The service name ] The end of the process （ Close the service ）
• Closing the service must not be used kill -9 Kill process ！！！ Because the service cannot be started when it is restarted ！

（ Two ） Close replica set

• When closing a replica set , The replica set master node must be closed last , If it closes before the replica node closes , Failover occurs , That is, the master node of the replica set changes from the original master node to the original replica node .

（ 3、 ... and ） Close the partitioned cluster

• Need to follow Mongos→Shard→Config Server In this order , because Config Server It records the metadata of the entire partitioned cluster , and Mongos and Shard Both need to work with Config Server Interaction , therefore Config Server Must be the last to close , and mongos As a client-side interaction component, it can be closed first , On the contrary .
• Shut down the services in the server , for example ：Config Server All three servers need to be shut down ,Shard All three servers have 3 Both need to be closed 3 individual ,Mongos Only the server nosql01 And the server nosql02 Yes, so just close both of them .

（ Four ） Command to start the service

• First you need to get into MongoDB Of bin Can only be opened under the directory
• Turn on Config Server：./mongod -f /opt/servers/mongodb_demo/shardcluster/configServer/configFile/mongodb_config.conf
• Turn on Shard1：./mongod -f /opt/servers/mongodb_demo/shardcluster/shard/configFile/mongodb_shard1.conf
• Turn on Shard2：./mongod -f /opt/servers/mongodb_demo/shardcluster/shard/configFile/mongodb_shard2.conf
• Turn on Shard3：./mongod -f /opt/servers/mongodb_demo/shardcluster/shard/configFile/mongodb_shard3.conf
• Turn on Mongos：./mongos -f /opt/servers/mongodb_demo/shardcluster/mongos/configFile/mongodb_mongos.conf

（ 5、 ... and ） Turn off the balancer Balancer

• Before closing the partitioned cluster , Need to be in the database gateway perform sh.stopBalancer() Command to turn off the balancer Balancer, Stop the migration and partition of blocks .

（ 6、 ... and ） Restart the fragmented cluster

• Need to be in the database gateway perform sh.startBalancer() Command to turn on the balancer
• Be careful ： After the security authentication is enabled, you need to use root The balancer can only be started after the user with permission has been authenticated , In which MongoDB Service process （ Specify the port number ） Executive sh.stopBalancer() Commands are added wherever they are root Authorize the user and execute sh.startBalancer() command .
• Relevant command （ Get into MongoDB After service ）：

use admin
db.auth(“itcastAdmin”,”itcastAdmin”)
db.createUser({
    user:”admin”,pwd:”admin”,roles:[{
    role:”root”,db:”admin”}]})
db.auth(“admin”,”admin”)
use gateway
sh.startBalancer()